KAVYA SUDHA, H.C.M. PAK

Transcription

1 Control of yellow mite, Polyphagotarsonemus latus (Banks) (Acari : Tarsonemidae) and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) (Acari : Tetranychidae) using mineral oil and newer acaricides KAVYA SUDHA, H.C.M. PAK 6101 DEPARTMENT OF AGRICULTURAL ENTOMOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES BANGALORE

2 Control of yellow mite, Polyphagotarsonemus latus (Banks) (Acari : Tarsonemidae) and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) (Acari : Tetranychidae) using mineral oil and newer acaricides AVYA SUDHA, H.C.M. PAK 6101 Thesis submitted to the UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE in partial fulfilment of the requirements for the award of the degree of Master of Science (Agriculture) in Agricultural Entomology BANGALORE JULY, 2008

3 i.exe DEPARTMENT OF AGRICULTURAL ENTOMOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BANGALORE CERTIFICATE This is to certify that the thesis entitled Control of yellow mite, Polyphagotarsonemus latus (Banks) (Acari : Tarsonemidae) and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) (Acari : Tetranychidae) using mineral oil and newer acaricides submitted by Ms. KAVYA SUDHA, H.C.M. in partial fulfilment of the requirement for the degree of Master of Science (Agriculture) in Agricultural Entomology of the University of Agricultural Sciences, Bangalore is a record of research work done by her during the period of her study in this university under my guidance and supervision and the thesis has not previously formed the basis of the award for the degree, diploma, associateship, fellowship or other similar titles. Bangalore July, 2008 (N. SRINIVASA) Major advisor Approved by : Chairman : (N. SRINIVASA) Members : (B. MALLIK) (C. PARVATHI) (N.C. NARASE GOWDA)

4 ACKNOWLEDGEMENT No scientific endeavour is a result of an individual s effort. I take this opportunity to look back on the path traversed during the course of this endeavour and to remember the guiding faces behind the task with a sense of gratitude. I am extremely rejoiced to express my deep sense of gratitude to Dr. N. Srinivasa, Professor & Senior Acarologist, Dept. of Agril. Entomology and the Chairperson of my Advisory committee for his valuable guidance, constructive criticism, everlasting patience and affection throughout the course of investigation. The case with which he has removed many obstacles in my path and given me the courage to go ahead in my entire endeavour is beyond the compare. I am indebted to the members of my Advisory committee, Dr. B. Mallik, Professor & Network Coordinator (Agril. Acarology), C. Parvathi, Associate Professor & Soybean Entomologist and N.C. Narase Gowda, Professor, Dept. of Horticulture GKVK, Bangalore, for their constant help and ameliorating this manuscript and valuable suggestion during the period of investigation I had taken up during the course of my investigation and later too. I am also thankful to Dr. C.T. Ashok Kumar, Professor of Entomology and Dr. N.G. Kumar, Professor and Head of Entomology for the facilities and the help during this study. I am also thankful to Dr. C. Chinnamade Gowda, Associate professor, Dr. S. Onkarappa, Research Associate,. Mr. Parandhama, non-teaching staff of AINP (Agril.Acarology) and all other teachers of Dept. of Agril. Entomology, UAS, Bangalore. My sincere gratitude to M/s BPCL, Mumbai, Nagarjuna Agrichem Ltd., Hyderabad, Northern Minerals Ltd., Gurgaon and Rallis India Ltd., Bangalore for providing various acaricidal compounds for my research work.

5 I am also thankful to Mr. Mounesh Udagatti, Karjagi and Mr. Rajashekariah, Agrahara Palya, who allowed me to conduct experiments in their fields. I find it different to express my words of gratitude to my parents, Mr. Maheshwarachar, Mrs. Latha and my sister Ms. Jyothsna, who always inspired me with their love and affection, which enabled to withstand all obstacles to reach this cherished goal. On a personal note, I am very glad to mention sincere support, words of encouragement, boundless love, unflagging inspiration and interest of my beloved friends, Nagalakshmi, Soumya, Manasa, Venkatesh, Gundappa, Devi, Shailaja, Kumarnag, Amini, Niranjan, Prasanna, Rajkumar, Ranjeeth and all my seniors. There are many others who in various ways, have contributed and assisted in this work. I express my sincere thanks to them. In case of any omission does not mean lack of gratitude. July, 2008 Bangalore (Kavya Sudha, H.C.M.)

6 ABSTRACT Investigations on the activity of mineral oil against different developmental stages of yellow mite, Polyphagotarsonemus latus and red spider mite, Tetranychus macfarlanei under laboratory conditions and the use of mineral oil in the control of these mites on chilli and okra crops in comparison with conventional and newer acaricides under field conditions were carried out during The mineral was least ovicidal, but with higher concentrations of 0.5%, 0.75%, 1.00%, 1.25% and 1.50%, maximum ovicidal activity observed was 11% against P. latus and 14% against T. macfarlanei. On mineral oil treated leaves upto 6h repellence of adults (46 to 89%) of both the mite species was prominent compared to that of their larvae (33 to 63%). The direct exposure of larvae of P. latus and T. macfarlanei to mineral oil resulted in their complete mortality (>98%), while with adults 69 to 93% mortality was observed. Field trial with mineral oil and newer acaricides against P. latus on chilli revealed that milbemectin (3.75g a.i./ha), diafenthiuron (375g a.i./ha) and chlorfenapyr (75g a.i./ha) were superior and accounted for 87 to 94% reduction in total population (including eggs and active stages) of the mite and dicofol (2.5ml/lit) caused upto 77% reduction. Mineral resulted in 78%, 72% and 73% reduction in the number of eggs, active stages and total number of mites, respectively. Considering the reduction in total population of T. macfarlanei on okra crop, diafenthiuron, dicofol and abamectin which caused 80 to 87% reduction were more effective, followed by propargite and fenazaquin. Effect of mineral to 1% was modest resulting in 53 to 62% reduction. It was inferred that mineral oil in view of its diverse activities like ovicidal, repellence and killing effect, can be used upto 1% concentration along with newer acaricides like milbemectin, diafenthiuron, fenazaquin and propargite in the integrated management of mite pests on chilli and okra crops. Signature of the Student Signature of the Major Advisor

7 CONTENTS CHAPTER TITLE PAGE NO. I INTRODUCTION 1 5 II REVIEW OF LITERATURE 6 18 III MATERIAL AND METHODS IV EXPERIMENTAL RESULTS V DISCUSSION VI SUMMARY VII REFERENCES 71 83

8 Table No LIST OF TABLES TITLE Treatment details of chilli field experiment at Karjagi near Haveri during Kharif 2007 Treatment details of okra field experiment at Agrahara Palya near Bangalore during Summer 2008 Effect of mineral oil on eggs of Polyphagotarsonemus latus and Tetranychus macfarlanei Walk-off response of larvae of P. latus on chilli leaves treated with mineral oil Walk-off response of larvae of T. macfarlanei on okra leaves treated with mineral oil Walk-off response of adults of P. latus on chilli leaves treated with mineral oil Walk-off response of adults of T. macfarlanei on okra leaves treated with mineral oil PAGE NO Effect of mineral oil on Polyphagotarsonemus latus -Mortality 36 9 Effect of mineral oil on Tetranychus macfarlanei - Mortality Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs) infesting chilli at Karjagi near Haveri (Kharif 2007) I spray Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs) infesting chilli at Karjagi near Haveri (Kharif 2007) II spray Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (active stages) infesting chilli at Karjagi near Haveri (Kharif 2007) I spray

9 Table No TITLE Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (active stages) infesting chilli at Karjagi near Haveri (Kharif 2007) II spray Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs+active stages) infesting chilli at Karjagi near Haveri (Kharif 2007) I spray Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs+active stages) infesting chilli at Karjagi near Haveri (Kharif 2007) II spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs) infesting okra at Agrahara Palya near Bangalore (Summer 2008) I spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs)infesting okra at Agrahara Palya near Bangalore (Summer 2008) II spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (active stages) infesting okra at Agrahara Palya near Bangalore (Summer 2008) I spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (active stages) infesting okra at Agrahara Palya near Bangalore (Summer 2008) II spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs+active stages) infesting okra at Agrahara Palya near Bangalore (Summer 2008) I spray Evaluation of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs+active stages) infesting okra at Agrahara Palya near Bangalore (Summer 2008) II spray PAGE NO

10 FIG. NO LIST OF FIGURES TITLE Bioefficacy of newer acaricides against eggs of yellow mite, Polyphagotarsonemus latus on chilli (I spray) Bioefficacy of newer acaricides against eggs of yellow mite, Polyphagotarsonemus latus on chilli (II spray) Bioefficacy of newer acaricides against active stages of yellow mite, Polyphagotarsonemus latus on chilli (I spray) Bioefficacy of newer acaricides against active stages of yellow mite, Polyphagotarsonemus latus on chilli (II spray) Bioefficacy of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs+active stages) on chilli (I spray) Bioefficacy of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs+active stages) on chilli (II spray) Bioefficacy of newer acaricides against eggs of red spider mite, Tetranychus macfarlanei on okra (I spray) Bioefficacy of newer acaricides against eggs of red spider mite, Tetranychus macfarlanei on okra (II spray) Bioefficacy of newer acaricides against active stages of red spider mite, Tetranychus macfarlanei on okra (I spray) Bioefficacy of newer acaricides against active stages of red spider mite, Tetranychus macfarlanei on okra (II spray) Bioefficacy of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs+active stages) on okra (I spray) Bioefficacy of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs+active stages) on okra (II spray) BETWEEN PAGES

11 FIG. NO TITLE Bioefficacy of newer acaricides against eggs of yellow mite, Polyphagotarsonemus latus on chilli (I & II spray) Bioefficacy of newer acaricides against active stages of yellow mite, Polyphagotarsonemus latus on chilli (I & II spray) Bioefficacy of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs+active stages) on chilli (I & II spray) Bioefficacy of newer acaricides against eggs of red spider mite, Tetranychus macfarlanei on okra (I & II spray) Bioefficacy of newer acaricides against active stages of red spider mite, Tetranychus macfarlanei on okra (I & II spray) Bioefficacy of newer acaricides against red spider mite, Tetranychus macfarlanei (eggs+active stages) on okra (I & II spray) BETWEEN PAGES

12 Introduction

13 I. INTRODUCTION Vegetables form an important dietary component supplying vitamins, proteins, carbohydrates and minerals needed for a balanced diet. India is a major vegetable producing as well as a consuming country. Chilli is one of the important commercial spice crops grown in India. Portugese traders introduced it to India and other parts of Asia around years ago (Berke and Shieh, 2000) and since then it has gained importance as an important spice cum vegetable crop. It is good source of vitamin A, C and E, fruits contain an alkaloid Capsaicin which imparts pungency and has high medicinal properties. India contributes one fourth of the world s chilli production with lakh tonnes cultivated over an area of 9.15 lakh hectares (Peter and Nybe, 2002). Of the total production, about per cent is consumed within the country and about 5-10 per cent is exported. Although chilli is cultivated in almost all parts of the country, Andhra Pradesh, Karnataka, Maharashtra, Tamil Nadu and Orissa constitute about 85 per cent of the total production. In Karnataka, chilli is grown in more than two lakh hectares with a production of about one lakh tonnes of dry chilli annually. The important chilli growing tracts in Karnataka are Haveri, Dharwad, Gadag, Koppal, Belgaum, Bagalkot and Raichur, of which only Haveri and Dharwad districts make up 72 and 60 per cent of total State s area and production, respectively. The pest spectrum of chilli is complex with more than 293 insects and a mite species debilitating the crop in the field as well as in storage. A total of 39 genera with 51 species of pests have been reported on the crop in nursery and in main field in Karnataka (Reddy and Puttaswamy, 1983). The major insects that attack chilli are aphids (Myzus persicae Sulzer, Aphis gossypi Glover), mite (Polyphagotarsonemus latus (Banks)) and thrips (Scirtothrips dorsalis Hood) (Berke and Shieh, 2000). In Karnataka, thrips, mites and white flies have been identified

14 as important sucking pests of chilli, of which leaf curl caused by mite and thrips is serious (Puttarudraiah, 1959). The yield losses due to these two pests are estimated to the tune of 50 per cent (Kandaswamy et al., 1990). Under certain situations the yield loss due to chilli mite alone may go up to 96 per cent, leading to complete failure of the crop (Kulkarni, 1962). Polyphagotarsonemus latus (Banks) which belongs to the family Tarsonemidae commonly known as yellow mite etc. is an important phytophagous mite with a wide host range including many cultivated crops like chilli, potato, sweet pepper, tomato, egg plant, beans and flower crops like Chrysanthemum, dahlia etc. (Gibson and Valenchia, 1978). The mechanical feeding injury and desapping by the immatures and adults of mites on apical parts of the plant coupled with suspected injection of toxins results in extensive leaf curling, elongation of petiole, leaf bud dropping, drying of growing points and drastic reduction in plant height. Such symptoms caused due to mites, thrips and the virus often referred to as Murda. Among the other cultivated vegetables grown in the country, okra (Abelmoschus esculentus L. Moench) is a commercially cultivated vegetable crop popularly called as Bhendi or Lady s finger. It is used in various culinary preparations like sabji, curry, fries and also eaten raw as salad. Though okra finds its origin in South Africa, India stands top in production and area. It is cultivated in an area of 3.25 lakh hectares with an annual production of lakh tonnes with a productivity of 9.7 tonnes/hectare (Anonymous, 2004). The major okra cultivating states include Uttar Pradesh, Bihar, Orissa, West Bengal, Andhra Pradesh, Karnataka and Assam (Anonymous, 2005). One of the important limiting factors in the cultivation of okra is insect and mite pests. Many of the pests occurring on cotton are found to ravage okra crop also. As high as 72 species of insects have been recorded on the crop

15 (Srinivasa Rao and Rajendran, 2002), of which the sucking pests like leaf hoppers, aphids, white flies, mites and fruit borers are known to cause severe damage to the crop. Red spider mite, Tetranychus macfarlanei (Baker and Pritchard) belongs to family Tetranychidae of order Prostigmata. It is a cosmopolitan species, having a wide host range, many cultivated crops like brinjal, tomato, cotton and okra are severly attacked. It causes various types of direct damage like loss of chlorophyll or bronzing of foliage, stunting of growth and reduction in yield. It generally feeds on the lower surface of the leaves as a result the infested leaves initially show speckling which later turn yellowish. It also damages the internal tissues punctured by their chelicerae. The mites spread to all parts of the plants as the population increases especially during dry periods and produce webbing over entire plant (Jeppson et al., 1975). To tackle the pest menace a number of chemical insecticides are liberally sprayed on this vegetable crop which leads to several problems like toxic residues, elimination of natural enemies, environmental disharmony and development of resistance. Due to the presence of pesticidal residues in the commodity there is also a risk of rejection of whole consignments during export. To overcome these problems identification of environmentally safe molecules with better pesticidal properties, lower mammalian toxicity, safety to natural enemies etc., which fits well in the IPM concept is the focal point of the present investigations. One of the oldest insecticides, petroleum oil is still an effective means of controlling certain insect pests. Horticultural oil technology advanced markedly from 1945 to Prior to this period, use of oil sprays was limited, hence they have not been used extensively in vegetables and other crops. Petroleum oils are also referred as mineral oil, dormant oil, summer oil, superior oil, horticultural

16 oil, spray oil etc. Mineral oil is defined as any oil found in the rock strata of the earth. Most horticultural oils are refined from crude oil. Oil acts as a contact poison until it evaporates. It also kills insect eggs by penetrating the shell and interfering with metabolic and respiratory processes (Anonymous, 2008a). Actively growing stages of insects or mites are more susceptible than the dormant stages. Oils have advantages of safety to applicator and the environment, with minimal effect on natural enemies. They can control a wide range of soft-bodied pests such as aphids, mites, thrips, white flies, mealybugs and psyllids. It is the only widely used class of chemicals to which insects or mites have not developed resistance so far. Keeping these in view the present investigations were undertaken with the following objectives: 1. To determine the activity of mineral oil against different developmental stages of yellow mite, Polyphagotarsonemus latus (Banks) infesting chilli and against red spider mite, Tetranychus macfarlanei (Baker and Pritchard) infesting okra. 2. Field evaluation of mineral oil and newer acaricides against yellow mite, P. latus on chilli and red spider mite, T. macfarlanei on okra.

17 Review of Literature

18 II. REVIEW OF LITERATURE Investigations on the activity of mineral oil and their use in the control of yellow mite, Polyphagotarsonemus latus (Banks) infesting chilli and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) infesting okra in comparison with newer acaricidal molecules were carried out during The literature available on various aspects of these mite species are presented here under. 2.1 Seasonal abundance of Polyphagotarsonemus latus (Banks) and Tetranychus macfarlanei (Baker and Pritchard) infesting chilli and okra, respectively Yellow mite, P. latus on chilli crop Dhooria and Bindra (1977) noticed high population of P. latus on chilli crop during August - December in Punjab. Mote (1976) noticed higher mite population on chilli crop in Rahuri (Maharashtra) from February to May and October to November than in other months. Ram et al. (1997) observed relatively higher incidence of P. latus on chilli plants 45 days after planting in Eastern Ghat highland zone of Orissa. In Tamil Nadu greater abundance of the chilli mite was observed between June & September months and beyond October - November with the onset of north east monsoon and in Gujarat summer crop during April to June harboured maximum number of mites and the kharif crop during October to November (Anonymous, ). Jones and Brown (1983) opined that the temperature adversely affected the chilli mite population. Rainfall was negatively correlated with mite population because rainfall removed the adult mite population. Under West Bengal conditions atmospheric temperature of 29.5 C to C and a relative humidity of 66% were found congenial for the build of the mite (Anonymous,

19 ). Morning relative humidity was positively correlated with mite population while evening relative humidity showed negative and non-significant correlation (Srinivasalu et al., 2002). Eswarareddy et al. (2007) recorded the incidence of P. latus in all the trials from September 2002 to March 2004 under protected conditions, the mite population was maximum during the month of March ( mites/leaf), when the average temperature and humidity were, 33.0 C and 63%, respectively. Hosamani et al. (2007) reported that chilli mite population showed a negative significant correlation with maximum and minimum temperature under Raichur conditions. The decline in mite population during April to July was due to high temperature prevailed during that period Red spider mite, T. macfarlanei & other species on okra and other crops Rai et al. (1991) studied the seasonal incidence of T. macfarlanei on okra crop at Navsari (Gujarat) during summer season. Incidence of the mite started in the month of April and reached peak during the middle of May and gradually declined following the onset of monsoon. Kumar and Sharma (1993) reported that spider mites in okra crop appeared in the first week of April reaching a peak in June and later declined in July and were not seen beyond September in Samastipur (Bihar). Sejalia et al. (1993) reported that during March and April, the development of red spider mite, T. macfarlanei was prolonged on okra crop due to low temperature and low relative humidity, while high temperature and high relative humidity shortened the duration. The incubation period for males and females was 4.31 days during March-April and 3.06 days during July-August. Combined larval and nymphal period was 5.69 days for male and 6.13 days for female during March-April, while it was 4.3 days and 5.07 days, for respective sexes during July-August.

20 Dhar et al. (2000) and Chinniah et al. (2007) found that the red spider mite, T. urticae population in okra had significant positive correlation with maximum temperature and negative correlation with relative humidity and rainfall in West Bengal and Tamil Nadu, respectively. Vegetative stage of the crop was more prone to the T. urticae damage and the yield loss was more. If infestation occurred at early stage of the crop as it gives sufficient time for population build up to flowering and fruiting stages resulting in more yield reduction than the plants infested by the mites at the later stages. The lower yield loss in okra due to T. urticae at the later stages might be due to the high plant vigour which can hasten the plant tolerance to T. urticae infestation. Kumaran et al. (2007) opined the yield loss was low due to mite infestation in later stages of the crop growth thus spraying at the later stages was not essential as the infestation of mite would have been compensated by the vigour of the plant. Thulsiram (1991) found that the population build up of T. macfarlanei on irrigated hybrid cotton at Tungabhadra Project area from October to November in Northern Karnataka and decreased there after, the population attained peak during November. Hegde (1993) reported that T. macfarlanei population on cotton crop at Raichur attained peak during November. Sharma and Pandey (1981) studied the relative seasonal incidence of two tetranychid species in the nursery and transplanted brinjal crop under Udaipur conditions. The mites were not found in the nursery, while the incidence of T. cinnabarinus started 3 weeks after transplanting (mid October) and T. neocaledonicus, appeared later (end of October). Both the species had almost similar population fluctuation during the season. Between October and January, population of both the species was low. Puttaswamy and ChannaBasavanna (1983) observed the effect of weather parameters on population of T. ludeni on brinjal. The population appeared through out the year, increased from April and reached peak numbers from May to July. Low rainfall, low relative humidity and

21 high temperature were correlated with the increase in their population. Similarly, a negative correlation was observed between low temperature and mite population by Bhagat and Singh (1999), rainfall was possibly the factor which contributed to the lower mite population. Mani et al. (2007) reported that the mite population increased from 2.20 mites/leaf in December 2006 and reached the peak of 10 mites/leaf in April, which revealed highly significant negative correlation between mite population and minimum temperature as well as relative humidity. Thus the weather factors, chiefly minimum temperature and relative humidity influenced the incidence of T. urticae on grapevine in Pune (Maharashtra). 2.2 Bioecology and natural enemies of P. latus and T. macfarlanei Karuppuchamy and Mohanasundaram (1987) studied the biology of P. latus on chilli. The average egg period was 36.20±3.60 h. The average larval period occupied 28.70±3.60 h. The average period of quiescent nymph was 21.57±1.79 h. Adult period occupied 8.66±1.57 days with a pre-oviposition period of 20.56±4.83 hours, the oviposition lasted for 7.9±0.9 days with an average fecundity of eggs per female. Karmakar (1995 and 1997) and Ahmed et al. (2000) studied the behaviour of P. latus. The mite laid eggs singly on the dorsal and ventral surfaces of leaves. The durations of different developmental stages were 36.04±3.12 hours for egg & 28.61±3.77 hours for larva. The total duration of development from egg to adult was 86.36±6.68 hours for female and 84.15±7.23 hours for male. Males lived for 7.24±0.77 days while, females lived for 8.66±1.57 days. The male to female ratio was 1: Silva et al. (1988) also studied the biology of P. latus on Capsicum at 20 C, 25 C and 30 C. An inverse relationship between developmental period and

22 temperature was observed for all the life stages. The period from egg to adult was the longest at 20 C (5.7 and 6.2 days for male and female, respectively). Oviposition was low at 20 C. The maximum fertility was observed at 25 C with an average 27.9 eggs per female. Adult longevity decreased with temperature, while fertility parameters increased with the temperature. Karuppuchamy et al. (1994) reported phytoseiid mite, Amblyseius ovalis (Euseius ovalis) as the potential predator of P. latus. Field release of A. ovalis at 5, 10, 15 and 20 mites per plant in chilli crop compared with recommended pesticides indicated that 20 mites per plant proved superior with the lowest counts of P. latus ( 0.61/3 leaves) as well as thrips (0.81/3 leaves) ( Manjunatha et al., 1999). Jose and Shah (1988) studied the biology of the mite, T. macfarlanei on cotton crop at Navsari in Gujarat during June, September, October and December months and reported that the incubation period was 3.30, 2.75, 2.93 and 4.5 days, respectively. The larval periods lasted for 1.00, 1.00, 1.13 and 2.71 days in the respective months. The protonymphs had an average period of 1.27, 0.96, 1.06 and 1.67 days and the deutonymph lasted for 1.33, 0.84, 0.74 and 1.00 days, respectively. The females took 7.73, 7.43, 7.42 and days for their development. The males completed their development in 6.12, 7.67 and 10.9 days during September, October and December months, respectively. 2.3 Chemical control of Polyphagotarsonemus latus (Banks) on chilli and Tetranychus macfarlanei (Baker and Pritchard) on okra P. latus on chilli Mote (1976) evaluated eleven acaricides over two seasons against chilli mite. Three applications of 0.2% micronized sulphur or sulphur dust and dicofol 0.05% were effective upto 7 days, while monocrotophos 0.05% and dimethoate

23 0.03% were effective upto 15 days. However, dicofol gave higher yields than others. Granular systemics applied in nursery and the sprays in the main fields, numerically gave better control and among the sprays, monocrotophos 0.03% was superior (Wadnekar and Deshpande, 1977). Kareem et al. (1977) noticed that application of phosalone 0.05% was most effective in suppressing chilli mite infestation. Patil and Dether (1979) showed that four sprays of monocrotophos 0.08% and oxydemeton-methyl were equally effective. However, the latter was on par with dimethoate 0.03% on the basis of mean population of mites. Monocrotophos at 0.5kg a.i./ha was significantly superior to quinalphos 0.5kg a.i./ha. The highest yield of dry chillies was recorded with monocrotophos. Thus considering yield and the net returns, monocrotophos, phosalone or cytralone (all at 0.5 kg a.i./ha) was recommended (Nawale and Pokharkar, 1977). Awate et al. (1981) found that dicofol 0.04%, sulphur 0.2%, actillic 0.05% and quinalphos 0.05% were more effective than monocrotophos 0.02% and dimethoate 0.03% against yellow mite on chilli crop. Ramudu and Reddy (1983) observed better efficacy of phosalone 0.01% followed by carbaryl + sulphur (Sevisulf) 0.15% and phosalone 0.05%. Sanap and Nawale (1986) noticed that Sevisulf 0.2% and monocrotophos 0.05% could afford protection upto 15 days from application. Among the seven insecticides tested triazophos 0.04% was significantly superior in reducing the mite population upto 7 days and the reduction in the population ranged from to 93.68%. The maximum cost benefit ratio of 1:9.9 was obtained with methyl-o-demeton application followed by phosalone (1:6.9) and monocrotophos (1:6.1) (Kandaswamy et al., 1987). Neem preparations like neem oil (1.00%), Neem guard (0.5%), Repelin (1%) and Biosol (0.5%) though gave significant control of mite, their performance was only next to synthetic insecticides. The chitin inhibitor Duphar 0.1% as spray

24 was least effective. Triazophos (0.1%) followed by phosalone (0.1%) and amitraz (0.1%) recorded higher red chilli yields (>3.25t/ha) (Rajashri et al., 1991). Application of monocrotophos (0.08%) caused maximum reduction in yellow mite population 24 hours after application compared to synthetic pyrethroids like cypermethrin, permethrin and fenvelarate (all at 0.01%) (Thakare et al., 1992). The lowest mite population and the highest yield were obtained with the application of dicofol compared to methyl-o-demeton and monocrotophos when sprayed at 95 and 110 days after sowing (Jeyranjan et al., 1995). Rae et al. (1996) reported that dicofol, chinomethionate, pyridaben and pyraclofos were effective with over 90% mortality of yellow mite in 17 days after application on pepper (Capsicum). g a.i./ha was found highly effective in reducing the yellow mite incidence for 7-14 days and recorded the highest yield compared to newer pesticides. g a.i./ha and g a.i./ha were promising, while g a.i./ha and g a.i./ha were least effective (Ahmed et al., 2000). Profenophos 50EC and profenophos 40% + cypermethrin 4% were evaluated for their relative efficacy against yellow mite, thrips and aphids on chilli crop in comparison with conventional pesticides in two different seasons by Dey et al. (2001). Profenophos alone at 1000 g a.i./ha and in combination at 440 g a.i./ha were highly effective against all the three pests and were found better than monocrotophos and diazinon. The plots treated with profenophos at 1000 g a.i./ha recorded the highest yield followed by profenophos at 500 g a.i./ha and profenophos in combination at 440 g a.i./ha with other pesticides. Gangopadhyay and Sarkar (2000) evaluated acaro-insecticides with two consecutive sprays against yellow mite infesting chilli. The overall performance

25 of sulphur and ethion (first spraying) and dicofol and ethion (second spraying) were better than dicofol, monocrotophos and endosulfan (first spraying) and sulphur, monocrotophos and endosulfan (second spraying). Field sanitation like eradication of weeds before planting and application of acaricides such as bromopropylate 0.5%, hexythiazox %, dicofol+tetradifon 1.5-2% and endosulfan 2% were thus recommended as a preventive measure. Walnuj and Pawar (2000) conducted study to determine the performance of fenazaquin in controlling P. latus on chilli cv. Phule Jyothi in Maharashtra. Among the different concentrations of fenazaquin, 150 g a.i./ha recorded a very effective control of mites. Fenazaquin at 300 g a.i./ha was not significantly superior either in mite control or yield. The two lower rates of fenazaquin resulted in poorer mite control and yields were not significantly better than in the untreated control. Ethion gave poorer control than dicofol and yields also did not differ significantly. Giraddi et al. (2001) evaluated synthetic chemicals and plant extracts against thrips and mites causing leaf curl in chilli cv. Byadgi. Of which, tank mixture of acephate + dicofol and monocrotophos + dicofol were more effective in mite suppression and plant damage reduction with increased fruit yield. Plant extracts were found ineffective against both thrips and mites Red spider mite, Tetranychus macfarlanei and other species on okra and other crops Patel and Yadava (1988) reported that dicofol at 0.1 and 0.05% was most effective giving 100% and 93.33% mortality of T. macfarlanei, respectively on okra under laboratory conditions. UC at 0.2% caused highest mortality of 90% followed by dicofol 0.05% under field conditions. Mortality percentage one day after treatment averaged to for 0.1% Sevisulf (carbaryl + sulphur), 71.6 for 0.2% UC 55284, for 0.05% dicofol and 57.21% for 0.08% Sulphur. Chawla

26 et al. (1989) also studied the efficacy of four acaricides against T. macfarlanei on okra in Rajasthan. They observed the toxicity of UC EC, methamidophos 40EC, dichlorvos 100 EC, dicofol 18.5 EC, phosalone 35EC, phosphomidan 100EC and ethion 50EC to increase two days after treatment. Rai et al. (1991) reported that dicofol 0.04% gave very good control of T. macfarlanei on okra crop followed by monocrotophos 0.05% at 24 hours and 7 days after the treatment. The least effective treatment was fenpropathrin % under field conditions. Krishnaiah and Tandon (1975) reported that 5 days after spraying dicofol, dimethoate and monocrotophos, the population of T. neocaledonicus on okra crop was reduced by 38-59% and after 14 days the population suppression was 46-89%. Peter et al. (1987) studied the efficacy of plictran 50W at g a.i./ha, dicofol 18.5 EC at 360 g a.i./ha and ethion 50EC against T. neocaledonicus on okra and found that cyhexatin at 350 and 400 g a.i./ha was superior after 14 days. Cyhexatin at 200, 250 and 300 g a.i./ha were equal in effectiveness after one week and superior to dicofol and ethion. Shankarappa et al. (1981) reported the efficacy of some pesticides against T. telarius on okra. Among the chemicals tested, Acrex 0.1% gave the highest mite mortality at 24h and 48h after treatment, while Acrex 0.05% at 7 days and dicofol 0.036% remained effective upto 14 days in checking the mite population. Peter and David (1988) observed that carbaryl, triazophos and synthetic pyrethroids resulted in out-break of T. ludeni on okra, while cartap did not. Dahira Beevi and Natarajan (1991) found wettable sulphur at 0.5% as most effective recording 63% reduction in T. ludeni population after 24 hours on okra. Kumar and Sharma (1993) reported that sulphur, dicofol, tetradifon and seed kernel extract on neem (Azadirachta indica) were effective in controlling T. ludeni on okra. Patel et al. (1995) found that dicofol, wettable sulphur and tetradifon

27 were effective against T. ludeni on okra with a cost benefit ratio of 1:20, 1:30 and 1:25, respectively. Szwedja (1994) reported that under high infestation pressure, a number of acaricides including abamectin, acinathrin, diafenthiuron and hexythiazox with fenpropathrin gave excellent control of T. cinnabarinus on green house tomato and cucumber. In all the cases, 14 days after treatment, more than 98% mortality of the motile stages was noticed. Price (1994) reported that a single application of bifenthrin 10WP at (1.12 and 3.36kg/ha) and a combination of hekakis, pyrethrins and rotenone reduced tetranychid populations. Abamectin and propargite resulted in reductions after 2 weekly applications. Dicofol, alanycarb and methomyl were ineffective in reducing tetranychid populations on strawberries. Fenazaquin was found to be most toxic to P. ulmi and T. urticae and the toxicity persisted for 15 days under field conditions. However, there were differences in toxicities to different populations of mite showing development of resistance and differences with the species of mites (Nath and Mahajan, 1998). Kulkarni and Mani (2007) reported that the Vertimec 1.9% EC resulted in significant reduction in spider mite population on grapes and it was found statistically on par with its higher doses of 0.75, 1.00 and 1.5ml/l. All the doses of Vertimec 1.9% EC (abamectin) were superior over standard check sulphur 2g/l and the untreated check and were not phytotoxic. Prasanna et al. (2007) observed that the minimum number of mites per 4cm 2 leaf area was observed after first spray in brinjal plots treated with hexythiazox (0.96) followed by abamectin (1.15), diafenthiuron (1.16) and fenazaquin (1.21). After the second spray, abamectin, hexythiazox, diafenthiuron,

28 fenazaquin and propargite recorded 0.10, 0.15, 0.20, 0.40 and 0.40 mites per cm 2 leaf area, respectively. Hexythiazox, abamectin and diafenthiuron were effective in reducing tetranychid mite population. Higher fruit yields were recorded in hexythiazox, abamectin, diafenthiuron and fenazaquin recording 27.78, 27.53, and t/ha, respectively. 2.4 Evaluation of oils against phytophagous mites Oils of plant origin Chandrashekarappa (1995) reported that NSKE and mohua oil at four per cent were effective against adults of T. urticae resulting in mortality ranging from 35 to 65 per cent. Similarly, Chandrashekar (1997) observed the mortality effect of neem, pongamia and mohua oils at 3, 4 and 5 per cent on adult females of T. urticae on French bean. Seventy two hours after treatment mohua oil and pongamia oil at 5 per cent caused complete mortality followed by 4% mohua oil (97% mortality), neem oil (90% mortality) and pongamia oil (87% mortality). Citronella oil 0.4 and 0.6 per cent was more consistent in inducing the walk-off response in the adult females of T. macfarlanei upto 24 hours, as more than 50 per cent of the individuals attempted to move out of treated okra leaves (Sugeetha, 1998). Srinivasa and Sugeetha (1999) studied the field efficacy of neem oil, pongamia oil and mohua oil (all at 3%) against T. macfarlanei on okra, and observed the adult mortality of per cent. Among the neem products, neem oil (1%) caused significantly higher mortality (79.60%) of okra red spider mites (Tetranychus sp.) compared to achook 1 per cent and nimbicidine 1 per cent which were on par with each other. Castor oil 1 per cent though superior to untreated control was inferior to neem products (Umamaheshwari et al., 1999). Kumaran et al. (2007) reported that among the neem products tested, neem oil and NSKE were least effective against red spider mite on okra, however, they were superior to pongamia oil.

29 Onkarappa (1999) reported that one day after application, mohua oil (1 to 2%) and neem oil (2%) caused and 74 per cent reduction in the number of adults of T. urticae, respectively, on rose grown in open fields. After 3 days and 7 days the per cent mortality varied from 55 to 77 and 45 to 84, respectively. Under polyhouse conditions two days after spraying low adult populations were observed with mohua oil (1.5%) and pongamia seed extract (1%) on par with neem oil (2%), pongamia oil ( %), pongamia seed extract (2%), mohua oil (0.75%) and NSKE (1-2%). Two days after second spray mohua oil ( %), pongamia oil (1.5%) and neem oil (1-2%) were found superior. Seven days after spraying fewer number of adults were observed with mohua oil ( %) and neem oil (1%) followed by neem oil (2%) and pongamia oil (1.5%) Petroleum oils Nowakowski (1982) noticed the effectiveness of emulsified mineral oil sprays and their mixtures with the phosphoro-organic compounds in comparison with classical summer acaricides against European red mite, Panonychus ulmi. Frutapon preparation containing the emulsified mineral oils applied during the bud bursting stage and the appearance of first leaves was very effective in control of spider mites during the stage of overwintering of eggs. This preparation was found effective when the standard preparations such as Roztoczol extra liquid 8 and Zolone liquid 35 were applied during the pink bud stage of apple trees. Agnello et al. (1994) evaluated highly refined horticultural petroleum oil, sunspray ultra fine on P. ulmi. Effective control was achieved with three applications of oil at 3% and 2%, starting at the petal fall stage and continuing on 2-3 week schedule. 1% oil provided control under conditions of moderate population pressure but required an additional spray in late July under severe population pressure. Rates of 0.25% and 0.05% resulted in unacceptable mite

30 numbers by midsummer. Phytotoxicity caused by the oil was most severe at the higher rates, but oil caused no leaf drop, even when moisture stressed. No effects of oil were seen on fruit finish or colour except for an increase in scarf skin of Law Rome at the highest rates of application. High pressure handgun oil sprays against a mixed population of mite eggs, immatures and adults reduced motile forms by 79-95%, at a concentration of 0.25% or more. Herron et al. (1996) evaluated six pesticides and two spray oils against Polyphagotarsonemus latus. Under laboratory conditions, the relative pesticide toxicities at the LC 50 level were abamectin g a.i./l, endosulfan g a.i./l, fenpyroximate g a.i./l, pyridaben g a.i./l, tebufenpyrad g a.i./l, dicofol g a.i./l, petroleum spray oil g a.i./l and canola oil g a.i./l. Herron et al. (1998) used the Potter s spray tower to determine the susceptibility of adult female (P. ulmi)) and two-spotted spider mite (T. urticae) to suffocation by petroleum spray oils (PSOs). The LC 95 values calculated for P. ulmi against C23 Ampol D-C-Tron NR and C21 Caltex Lovis were 104 and 165 g cm -2, respectively. For T. urticae the values were 169 and 207 g cm -2, respectively. The results were consistent with established relationships between PSO efficacy and increasing PSO molecular weight. Nicetic et al. (2001) conducted four experiments on greenhouse roses to assess the effectiveness of the petroleum spray oil (PSO), D-C-Tron Plus, against two-spotted mite and to evaluate and use in combination with the predatory mite Phytoseiulus persimilis Athias-Henriot. The results showed that 0.5% PSO applied fortnightly to roses gave excellent protection from T. urticae infestation when the mite population was not established. However, PSO applied after roses were infested with T. urticae above the economic threshold only stabilised populations without reducing them below the threshold. Populations of P.

31 persimilis in the upper and lower canopies were unchanged after two sprays of PSO at 7 day intervals, and application of PSO to the upper canopy was as effective as P. persimilis. Combining PSO with P. persimilis gave better control of T. urticae than using P. persimilis alone. Comparison of a control program for T. urticae based on the monitored use of synthetic miticides with that based on calendar application of PSO revealed that both gave equally effective control, highlighting the benefits of combining PSO and P. persimilis in an integrated pest management program for T. urticae on roses. Rae et al. (2000) observed the efficacy of three different oil formulations on sweet orange and pummelo. Trees sprayed with any type of oil had lowest pest population than the unsprayed trees, the heaviest oil provided the best control of mite. On sweet orange there was no evidence of phytotoxicity, but the external quality of fruit was found generally improved over time. However, on pummelo, oil sprays were unable to improve the external fruit quality. Alan (2003) opined that the use of horticultural oil was as acceptable as any other methods against mite pests. He also stated that mites quickly developed immunity to any product (except horticultural oil, which killed them by smothering), however, over use of horticultural oil might cause fungal problems. The direct toxicity of some mineral and plant oils to the eggs and females of two spotted spider mite T. urticae has been documented. KZ oil was more toxic to the egg stage compared to adult females. In contrast, Natural oil had toxic effect on both the stages of T. urticae. Bio-dux oil was proved to be toxic to adult female and relatively non-toxic to egg stage. Females of T. urticae suffered depression in reproduction and shortened longevity when kept on leaves treated with different oils (Anonymous, 2008b).

32 Material and Methods

33 III. MATERIAL AND METHODS The present investigations on the efficacy of newer synthetic acaricides including mineral oil against yellow mite, Polyphagotarsonemus latus (Banks) infesting chilli and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) infesting okra were conducted at the Department of Entomology, University of Agricultural Sciences, Bangalore during the period of The laboratory experiments were carried out at the Acarology section of the Department of Agricultural Entomology, GKVK, Bangalore and field experiment on chilli was conducted in farmer s field in the village Karjagi near Haveri during kharif 2007 and a field experiment on okra in farmer s field in the village Agrahara Palya near Bangalore during summer Material used and the methods followed for different experiments are presented in this chapter. 3.1 Maintenance of Polyphagotarsonemus latus (Banks) and Tetranychus macfarlanei (Baker and Pritchard) culture in the laboratory/greenhouse Polyphagotarsonemus latus (Banks) Leaves of Byadgi chilli variety infested by yellow mites in open field condition were brought to the laboratory and the mites were transferred on to French bean leaves placed on moist cotton wads in Petri plates in the laboratory. Mites were allowed to lay eggs and colonize for days. French bean leaves were changed periodically with fresh leaves. The mite culture was maintained in the laboratory on French bean leaves as well as in the greenhouse on potted chilli plants and used as a starter culture for further studies Tetranychus macfarlanei (Baker and Pritchard) Spider mite infested okra leaves from the field were brought to the laboratory in polyethylene covers. One adult female and two to three male mites were picked and released on to okra leaf bits measuring 2.5cm 2.5cm such

34 leaf bits with mites were separately maintained and allowed to colonise for next 9-10 days. Microscopic slides with male and female mites were prepared separately for each of the leaf bits and were identified. Leaf bits with mite species, T. macfarlanei were pooled and used as starter culture for further studies. These mites were also released on potted okra plants for multiplication in the greenhouse. 3.2 Evaluation of mineral oil against P. latus and T. macfarlanei P. latus and T. macfarlanei cultures maintained in the laboratory/glasshouse of Department of Agril. Entomology were used for bioassay studies to determine the activity of mineral oil against eggs and active stages of P. latus and T. macfarlanei. Mineral oil formulation, MAK all Season HMO from Bharath Petroleum Corporation Ltd., Mumbai was evaluated at 0.25%, 0.50%, 0.75%, 1.00%, 1.25% and 1.50% along with dicofol at 0.05% Ovicidal activity The ovicidal activity of mineral oil was assessed at concentrations from 0.25% to 1.50% using chilli leaves with P. latus eggs. Chilli leaf bits measuring 2cm 2cm with atleast eggs were placed on moist cotton wad in a Petri plate and each such chilli leaf bit served as one replication. Three such replications were maintained for each dose of mineral oil along with dicofol 0.05% and control (water spray). One ml of the desired concentration of mineral oil was used for treating the eggs under a Potter s spray tower operated at 15 to 20 lbs/inch 2. In all the treatments the eggs were observed for hatching at 24 h interval for 3-4 days or till all the eggs in water sprayed control hatched. To determine the ovicidal activity of mineral oil against spider mite T. macfarlanei, few active female mites were released on okra leaf bits measuring 2cm 2cm placed on moist cotton wad in a Petri plate. The female mites were

35 allowed to lay eggs for 8-10 h. About eggs laid on each of these leaf bits served as one replication. Three such replications were maintained for each treatment including dicofol 0.05% and control (water spray). One ml of the desired concentration of mineral oil was used for treating the eggs under Potter s spray tower operated at 15 to 20 lbs/inch 2. The eggs were observed for hatching at 24 h interval for 5-6 days or till all the eggs in water sprayed control hatched. The percentage of egg hatching in different treatments was recorded. The percentage data were subjected to angular transformation and analysed statistically using ANOVA techniques for Completely Randomised Design to compare the ovicidal activity of different treatments Walk-off response or repellent action A known number larvae/adults (20-30) released on chilli/okra leaf bits measuring 2cm X 2cm placed on moist cotton wad in Petri plates were made used to ascertain the walk-off response. Each leaf bit served as one replication, three such replications were maintained for each of the concentrations of mineral oil, dicofol 0.05% and control (water treated) and were treated using Potter s spray tower operated at lbs/inch 2. The number of larvae/adults which were found trapped or entangled to the moist cotton wad along the edges of the leaf bit was recorded 6, 12 and 18 h after release and the per cent walk-off was computed for larvae and adults separately (Penman et al., 1986). At each observation, individuals which were found trapped or drowned in the wet cotton wad were released back on to the respective leaf bits carefully using a fine camel hair brush and observations were continued.

36 3.2.3 Mortality To ascertain the killing effect, a known number of larvae/female adults (20-30) were released on chilli/okra leaf bits measuring 2cm 2cm placed on moist cotton wad in a Petri plate. Each leaf bit served as one replication, three such replications were maintained for each of the treatments and leaf bits were treated with desired concentration of mineral oil using Potter s spray tower operated at 15-20lbs/inch 2. At 24h interval the number of individuals (larvae/adults) killed was recorded upto 72h and the per cent mortality was computed treatment-wise. Individuals which did not respond to the touch by the fine camel hair brush or moribund were considered as dead. Walk-off response and mortality data recorded were corrected using Abbott s formula (1925), depending upon the mortality in water treated control. The data in percentages were subjected to arcsine transformation and analysed statistically following the Analysis of Variance method for Completely Randomized Design and the results were interpreted at five per cent level of significance Phytotoxicity of mineral oil on chilli and okra To ascertain the phytotoxic effects, the experiment was carried out in the Acarology experimental field at GKVK, Bangalore. Two months old healthy plants (chilli and okra) in 5m rows were selected for treatment with different concentrations of mineral oil viz., 0.25%, 0.5%, 0.75%, 1.00%, 1.25% and 1.5% along with water spray as control. The different concentrations of mineral oil were sprayed using a Ganesh sprayer. The treated plants were observed for visual symptoms of phytotoxicity like necrosis, scorching, hyponasty, epinasty, vein clearing etc. for 10 days especially on the tender parts.

37 3.3 Field bioefficacy of newer acaricides including mineral oil against yellow mite, Polyphagotarsonemus latus (Banks) on chilli and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) on okra Yellow mite, Polyphagotarsonemus latus (Banks) on chilli A field experiment was carried out in farmer s field in Karjagi near Haveri during kharif weeks old chilli crop of variety Byadgi Dabbi with uniform mite infestation was used to lay out the experiment in Randomized Complete Block Design with twelve treatments and three replications. The plot size was 5m 5m, with a row spacing of 90cms and plant to plant spacing of 60cms. Details of the acaricides used in the experiment are provided in Table 1. The test chemicals were applied as foliar sprays using a high volume knapsack sprayer twice at fortnightly interval during October November 2007, when the mite infestation was fairly high. The quantity of spray fluid used was 750 litres/ha. For recording observations, six plants were selected at random from each plot and from each plant one tender shoot tip with at least six leaves were sampled. Mite population was recorded by counting the number of eggs and active stages (larvae, nymphs and adults) on top six leaves using a stereobinocular microscope. Such observations on mite population were recorded before application i.e. pre-treatment and 3, 7, 10 and 14 days after each application i.e. post-treatment. Population was expressed as the mean number per six leaves Red spider mite, Tetranychus macfarlanei (Baker and Pritchard) on okra Field trial on okra (variety Nirmala) was carried out in a farmer s field in Agrahara Palya near Bangalore during summer The experiment was laid out in a Randomized Complete Block Design with 12 treatments and three replications.

38 Table 1 : Treatment details of chilli field experiment at Karjagi near Haveri - Kharif 2007 Treatments Test chemical Dosage or concentration T 1 Mineral oil 0.25% T 2 Mineral oil 0.50% T 3 Mineral oil 0.75% T 4 Mineral oil 1.00% Trade name and Source MAK All season HMO ; Bharath Petroleum Corp. Ltd., Mumbai. T 5 Chlorfenapyr 10 EC 75 g a.i./ha Intrepid ; BASF India Ltd., Mumbai T 6 Diafenthiuron 50 WP 375 g a.i./ha Pegasus ; Syngenta India Ltd., Mumbai Magister ; T 7 Fenazaquin 10 EC 125 g a.i./ha EI Dupont India Pvt Ltd., Gurgaon T 8 Milbemectin 1 EC 3.75 g a.i./ha Milbeknock ; Nagarjuna Agrichem Ltd., Hyderabad T 9 Profenophos 50 EC 190 g a.i./ha Curacron ; Syngenta India Ltd., Mumbai Omite ; T 10 Propargite 57 EC 570 g a.i./ha Northern Minerals Ltd., Gurgaon T 11 Dicofol 18.5 EC 2.5 ml/lit. Colonel ; Indofil Chemical Co. Ltd., Mumbai T 12 Control Water spray --

39 The plot size was 4m 4m with a row to row spacing of 60cm and plant to plant spacing of 30cm. Details of acaricides evaluated are provided in the Table 2. Two months old okra crop with high infestation of red spider mite was sprayed with different acaricides twice at 15 days interval. The spray fluid was 625 litres/ha. Pretreatment observation was recorded one day before application and the post-treatment observations were recorded 3, 7, 10 and 14 days after first and second spray. For recording observations, four plants were randomly selected from each plot. From each plant one leaf from top, middle and bottom canopies were sampled and brought to the laboratory in polyethylene covers. The number of eggs and active stages in 2cm 2cm area on each of the leaves sampled was recorded in the laboratory using a stereobinocular microscope. The mite population was expressed as the mean number of eggs or active stages or total (eggs + active stages) per 4 sq. cm leaf area. To compare the different acaricidal treatments the mite population data were subjected to x+0.5 transformation and analysed statistically following Analysis of Variance technique (ANOVA) for Randomized Complete Block Design (RCBD) and the results were interpreted at 5% level of significance. To compare the effectiveness of different chemicals, per cent reduction in the population of the mites (eggs or active stages or eggs + active stages) over control (water spray) was calculated using Henderson and Tilton s formula (1955) as below. Per cent reduction over control = 1 [(Ta/Tb) (Cb/Ca)] 100 Where, Ta = population in treated plot after spray/treatment Tb = population in treated plot before spray/treatment Ca = population in control plot after spray/treatment Cb = population in control plot before spray/treatment

40 Table 2 : Treatment details of okra field experiment at Agrahara Palya near Bangalore during Summer 2008 Treatments Test chemical Dosage or concentration T 1 Mineral oil 0.25% T 2 Mineral oil 0.50% T 3 Mineral oil 0.75% T 4 Mineral oil 1.00% Trade name and Source MAK All season HMO ; Bharath Petroleum Corps Ltd., Mumbai. T 5 Abamectin 1.9 EC 6 g a.i./ha Vertimec ; Syngenta India Ltd., Mumbai T 6 Buprofezin 25 SC 150 g a.i./ha Applaud ; Rallis India Ltd., Bangalore T 7 Chlorfenapyr 10 EC 75 g a.i./ha Intrepid ; BASF India Ltd., Mumbai T 8 Diafenthiuron 50 WP 375 g a.i./ha Pegasus ; Syngenta India Ltd., Mumbai Magister ; T 9 Fenazaquin 10 EC 125 g a.i./ha EI Dupont India Pvt Ltd., Gurgaon (Haryana) T 10 Propargite 57 EC 425 g a.i./ha Omite ; Northern Minerals Ltd., Mumbai T 11 Dicofol 18.5 EC 2.5 ml/lit. Colonel ; Indofil Chemical Co. Ltd., Mumbai T 12 Control Water spray --

41 Experimental Results

42 IV. EXPERIMENTAL RESULTS Investigations on the chemical control of yellow mite, Polyphagotarsonemus latus (Banks) infesting chilli and red spider mite, Tetranychus macfarlanei (Baker and Pritchard) infesting okra using mineral oil and newer acaricides were carried during at the Department of Entomology, University of Agricultural Sciences, Bangalore. The results of these investigations are presented in this chapter. 4.1 Effect of mineral oil on yellow mite, P. latus and red spider mite, T. macfarlanei Ovicidal activity The eggs of tarsonemid mite and spider mite treated with different concentration of mineral oil and their hatchability was observed. Data on relative ovicidal activity of mineral oil and dicofol are presented in Table 3. The ovicidal effect of different concentration of mineral oil on P. latus ranged from 4.59 to compared to 11.43% observed with dicofol 0.05 per cent treated eggs. Least toxicity was observed with mineral oil at 0.25 per cent concentration (4.59% egg mortality). The maximum ovicidal activity observed was 11.26% at mineral oil 1 per cent on par with mineral oil at 1.5 per cent and dicofol (Table 3). Similar trend was observed with eggs of T. macfarlanei exposed to different concentration of mineral oil. Mineral oil at 0.25 per cent was found least ovicidal. But maximum ovicidal activity observed with other concentrations of mineral oil did not exceed 14%. Mineral oil at 1.5 per cent and dicofol were statistically on par recording an egg mortality of to 14.06%.

43 Table 3 : Effect of mineral oil on eggs of Polyphagotarsonemus latus & Tetranychus macfarlanei Treatments No observed effect in untreated control **: Significant Figures in parantheses are angular transformed values. Mortality (%) after 3 days P. latus T. macfarlanei Mineral oil 0.25% (12.32) a (4.38) a Mineral oil 0.5% (16.02) b (10.95) b Mineral oil 0.75% (16.25) b (14.31) bc Mineral oil 1% (19.54) c (17.64) cd Mineral oil 1.25% (17.28) bc (16.07) bc Mineral oil 1.5% (18.88) bc (22.01) d Dicofol 0.05% (19.75) c (19.77) cd F test ** ** SEM ± (1.01) (1.92) CD at P=0.05 (3.07) (5.84)

44 4.1.2 Walk-off response Data on the walk-off response of P. latus and T. macfarlanei on chilli and okra leaves treated with different concentrations of mineral oil are presented in Table 4, 5, 6 and Walk-off response of larvae Per cent walk-off of P. latus on chilli and T. macfarlanei on okra leaves treated with mineral oil differed significantly upto 6h and 6h 12h, respectively. Six hours after treatment walk-off response of P. latus larvae was maximum in mineral oil at 1.25 per cent treated chilli leaves (62.16%) followed by mineral oil at 1.5 per cent and dicofol treatment at 0.05 per cent (61.07% and 61.05%, respectively). Gradual decrease in walk-off response was observed between 6h and 18h. There were no significant differences with respect to walkoff on mineral oil treated leaves beyond 6 hours (Table 4). The extent of walk-off of larvae observed on mineral oil or dicofol treated leaves was to 33.31% at 12 h which declined to to 27.76% at 18h. Six hours after treatment walk-off response of the T. macfarlanei larvae was maximum on mineral oil at 1.5 per cent treated okra leaves (63.27%) followed by mineral oil at 1.25 per cent and 1.00 per cent, with similar walk-off response of 62.16% and 59.94% respectively. Gradual decrease in walk-off response observed upto 18 hours was evident with different concentrations of mineral oil and also with dicofol treatment. Twelve hours after treatment walk-off response of the larvae was maximum in dicofol treated leaf bit (47.73%) followed by mineral oil at 1.25 per cent and 1.5 per cent (43.29% and 42.18% walk off, respectively). After eighteen hours, though no significant differences among different concentrations of mineral oil as well as dicofol with regard to the extent of walk-off was observed, still mineral oil treated leaves repelled to 37.75% larvae compared to 28.87% walk off with dicofol (Table 5).

45 Table 4 : Walk-off response of larvae of P. latus on chilli leaves treated with mineral oil Per cent larvae showing walk-off Treatments 6 hours 12 hours 18 hours Mineral oil 0.25% (35.18) a (30.27) (29.45) Mineral oil 0.5% (39.2) ab (28.71) (24.61) Mineral oil 0.75% (43.69) bc (30.27) (26.50) Mineral oil 1% (48.80) cd (35.23) (31.73) Mineral oil 1.25% (52.09) d (30.27) (26.50) Mineral oil 1.5% (51.42) d (29.60) (25.60) Dicofol 0.05% (51.45) d (28.83) (21.30) F test ** NS NS SEM ± (2.00) (1.77) (2.15) CD at P=0.05 (6.05) (5.38) (6.53) No observed effect in untreated control **: Significant; NS: Nonsignificant; Figures in parantheses are angular transformed values.

46 Table 5 : Walk-off response of larvae of T. macfarlanei on okra leaves treated with mineral oil Per cent larvae showing walk-off Treatments 6 hours 12 hours 18 hours Mineral oil 0.25% (38.54) a (31.74) ab (29.58) Mineral oil 0.5% (42.41) ab (27.04) a (31.05) Mineral oil 0.75% (45.61) bc (32.44) ab (31.74) Mineral oil 1% (50.76) d (37.88) bc (32.33) Mineral oil 1.25% (52.06) d (41.14) c (35.88) Mineral oil 1.5% (52.70) d (40.47) c (37.88) Dicofol 0.05% (48.80) cd (43.69) c (32.44) F test ** ** NS SEM ± (1.66) (2.07) (1.95) CD at P=0.05 (5.04) (6.27) (5.92) No observed effect in untreated control **: Significant ; NS: Nonsignificant; Figures in parantheses are angular transformed values.

47 Walk-off response of adults Per cent walk-off of P. latus adults on chilli and T. macfarlanei on okra leaves treated with mineral oil differed significantly at all intervals of 6, 12 and 18 hours (Table 6 and 7). Six hours after treatment walk-off response of P. latus adults was maximum in mineral oil at 1.5 per cent (88.8%) followed by mineral oil at 1 per cent and 1.25 per cent and dicofol (77.7% to 82.14% walk off). Gradual decrease in walk-off response observed upto 18 hours. Twelve hours after treatment the highest number of individuals walked-off was recorded in mineral oil at 1.00 per cent (75.48%) followed by dicofol and mineral oil at 1.5 per cent with the corresponding walk-off of 72.15% and 63.29%, respectively. Eighteen hours after treatment the maximum walk-off response was recorded with dicofol (59.94%) on par with walk-off observed with mineral oil at 1.5 per cent (Table 6). Six hours after treatment walk-off response of the T. macfarlanei adults was maximum on okra leaves treated with mineral oil at 1.5 per cent (82.14%) on par with mineral oil 1 to 1.25 per cent and dicofol (69.95 to 79.92% and 78.81% walkoff, respectively). Gradual decline in walk-off response was observed upto 18 hours. After twelve hours the maximum number of individuals walk-off from dicofol treatment (55.5%) immediately followed by mineral oil 1.25 per cent. Again after eighteen hours the maximum walk-off was observed in dicofol (43.51%). However, mineral oil at 0.25 to 1.5 per cent caused similar walk-off at 12h and 18h (Table 7) and were statistically on par Mortality Data on the killing effect of mineral oil on P. latus and T. macfarlanei are presented in Table 8 and 9.

48 Table 6 : Walk-off response of adults of P. latus on chilli leaves treated with mineral oil Per cent adults showing walk-off Treatments 6 hours 12 hours 18 hours Mineral oil 0.25% (42.41) a (35.82) a (30.27) a Mineral oil 0.5% (56.16) bc (50.74) bcd (34.53) a Mineral oil 0.75% (48.80) ab (44.97) b (34.40) a Mineral oil 1% (65.13) de (60.37) e (33.17) a Mineral oil 1.25% (81.92) f (46.89) bc (41.14) b Mineral oil 1.5% (70.75) e (52.79) cd (48.80) c Dicofol 0.05% (62.36) cd (58.42) de (50.74) c F test ** ** ** SEM ± (2.61) (2.42) (1.9) CD at P=0.05 (7.91) (7.35) (5.76) No observed effect in untreated control **: Significant; Figures in parantheses are angular transformed values.

49 Table 7 : Walk-off response of adults of T. macfarlanei on okra leaves treated with mineral oil Per cent adults showing walk-off Treatments 6 hours 12 hours 18 hours Mineral oil 0.25% (46.89) ab (25.38) a (23.84) a Mineral oil 0.5% (52.95) ab (31.77) ab (20.31) a Mineral oil 0.75% (54.26) ab (26.05) ab (23.37) a Mineral oil 1% (56.93) abc (30.46) ab (24.90) a Mineral oil 1.25% (63.54) bc (38.48) bc (24.83) a Mineral oil 1.5% (65.39) c (37.00) abc (29.29) a Dicofol 0.05% (62.69) bc (48.16) c (42.41) b F test * * ** SEM ± (3.58) (4.24) (3.45) CD at P=0.05 (10.88) (12.87) (10.45) No observed effect in untreated control *: Significant; **: Significant Figures in parantheses are angular transformed values.

50 P. latus (larvae and adults) Mineral oil at all the concentrations viz, 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50 per cent caused complete mortality of P. latus larvae on par with dicofol (Table8). Mineral oil at 0.25 to 0.75 per cent resulted in 70 to 80% mortality of adults while to 93.33% mortality was observed with mineral oil at 1 to 1.5 per cent. Adult mortality of 94.44% was observed on dicofol treated chilli leaves (Table 8) T. macfarlanei (larvae and adults) As observed with P. latus mineral oil at 0.25 to 1.5 per cent and dicofol resulted in complete mortality of T. macfarlanei larvae on treated okra leaves (Table 9). T. macfarlanei adults released on mineral oil treated okra leaves ranged from to 90%, while 85.56% mortality was recorded on dicofol treated leaves. Killing effect of mineral oil was statistically similar at all the concentrations (except at 1 and 1.5 per cent) (Table 9) Phytotoxicity of mineral oil on chilli and okra Observations on phytotoxicity were recorded at 24 h interval upto 10 days. On both chilli and okra plants two days after treatment with mineral 1.25 and 1.5 per cent scorching of tender leaves was observed in 10-15% of the plants. However, the scorching effect was found recovered after 5 days. Hence the application of mineral oil at 1.25 and 1.5 per cent showed mild phytotoxicity on chilli and okra.

51 Table 8 : Effect of mineral oil on Polyphagotarsonemus latus Mortality Treatments Corrected mortality (%) Larvae (after 48 h) Adults (after 72 h) Mineral oil 0.25% (82.79) (56.81) a Mineral oil 0.5% (89.42) (63.64) abc Mineral oil 0.75% (86.11) (60.41) ab Mineral oil 1% (89.42) (73.47) bcd Mineral oil 1.25% (89.42) (80.76) d Mineral oil 1.5% (86.11) (77.44) cd Dicofol 0.05% (82.79) (76.51) cd F test NS * SEM ± (2.51) (4.81) CD at P=0.05 (7.60) (14.59) *: Significant; NS: Nonsignificant; Figures in parantheses are angular transformed values.

52 Table 9 : Effect of mineral oil on Tetranychus macfarlanei Mortality Treatments Corrected mortality (%) Larvae (after 48 h) Adults (after 72 h) Mineral oil 0.25% (86.11) (56.20) Mineral oil 0.5% (86.11) (68.25) Mineral oil 0.75% (89.43) (59.14) Mineral oil 1% (89.43) (74.64) Mineral oil 1.25% (89.43) (66.57) Mineral oil 1.5% (89.43) (71.72) Dicofol 0.05% (89.43) (68.24) F test NS NS SEM ± (1.77) (4.69) CD at P=0.05 (5.37) (14.25) NS: Nonsignificant; Figures in parantheses are angular transformed values.

53 4.2 Evaluation of mineral oil and newer acaricides against mites infesting chilli and okra crops Bioefficacy against yellow mite, Polyphagotarsonemus latus (Banks) Newer acaricides and mineral oil were evaluated against yellow mite on 8-10 weeks old chilli crop in a farmer s field in Haveri. Before spraying, pretreatment observation on mite population including eggs and active stages was recorded. After 3, 7, 10 and 14 days, post treatment observations were recorded. Abundance of eggs Three days after application, diafenthiuron (375 g a.i./ha) and milbemectin (3.75 g a.i./ha) treated plots recorded least number of eggs (0.6 eggs/six leaves) and these were statistically on par with fenazaquin (125 g a.i./ha), chlorfenapyr (75 g a.i./ha) and dicofol (2.5ml/lit). Remaining treatments including untreated control harboured maximum number of eggs (upto 36.8 eggs/six leaves) (Table 10). Different mineral oil concentrations were on par with each other. Reduction in egg population over control was maximum in diafenthiuron treated plot (97.84%) followed by milbemectin treated plot (96.31%). Similar trend was observed after seven days, diafenthiuron, milbemectin and chlorfenapyr treated plots recorded fewer number of eggs (0.9 eggs/six leaves) and were statistically on par with each other. The per cent reduction in the number of eggs per six leaves over control was maximum with diafenthiuron (95.29%) followed by milbemectin (91.95%). In untreated control as high as 13.2 eggs/ six leaves was recorded. After ten days, milbemectin was statistically superior with minimum number of eggs (0.2 eggs/six leaves) and it was on par with chlorfenapyr,

54 dicofol, diafenthiuron, fenazaquin and mineral oil (0.75 to 1.00 per cent). Reduction in egg population was maximum over control in milbemectin treated plot (97.75%). More number of eggs was recorded in the untreated control, propargite and profenophos treated plots (10.5 to 28 eggs/six leaves). Similar trend was observed fourteen days after treatment milbemectin, chlorfenapyr and diafenthiuron with less number of eggs, 0.5, 0.6 and 2.8 eggs/six leaves, respectively and were statistically on par. Dicofol, mineral oil (all concentrations), fenazaquin and propargite (570 g a.i./ha) treated plots also recorded fewer number of eggs. In untreated control and profenophos as high as 12.7 and 18.3 eggs/six leaves were recorded. Reduction in egg population was maximum in milbemectin treated plot (95.35%) followed by chlorfenapyr with 93.55% reduction (Fig. 1). With second application also treatments differed significant at 3, 7, 10 and 14 days with regard to egg population (Fig. 2). Chlorfenapyr recorded least number of 0.5 eggs/six leaves and it was on par with most of the treatments except fenazaquin, profenophos and control (Table 11). The maximum number of eggs was recorded in profenophos (@190 g a.i./ha) treatment (39.2 eggs/six leaves). In chlorfenapyr treated plot which harboured least number of eggs, the per cent reduction in egg population was 96.39% similar to the one observed in diafenthiuron. Similar trend was observed upto 14 days after second application with regard the effect of different acaricides including mineral oil in bringing down the population of eggs (Table 11). Profenophos treated plots recorded more number of eggs (14.9 to 39.2) than with untreated control (2.6 to 18.9 eggs/six leaves).

55 Table 10 : Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs) infesting chilli at Karjagi, Haveri (Kharif 2007) I spray Treatments Dosage/ concentration Mineral oil 0.25% Mineral oil Mineral oil Mineral oil Chlorfenapyr 10 EC Diafenthiuron 50 WP Fenazaquin 10 EC Milbemectin 1 EC Profenophos 50 EC Propargite 57 EC Dicofol 18.5 EC Control 0.50% 0.75% 1.00% 75 g a.i./ha 375 g a.i./ha 125 g a.i./ha 3.75 g a.i./ha 190 g a.i./ha 570 g a.i./ha 2.5 ml/lit. Water spray Mean number of eggs per six leaves First Spray Before 3 DAT 7 DAT 10 DAT 14 DAT (3.5) (3.9) b (2.4) abcd (3.0) bcd (1.8) abc (4.9) (6.1) c (2.7) bcd (2.9) bcd (2.5) abcd (4.5) (3.7) b (3.3) cd (2.4) abcd (2.9) bcd (4.4) (3.9) b (1.5) ab (2.2) abcd (1.9) abc (3.6) (1.1) a (1.1) a (1.1) a (1.0) a (5.0) (1.0) a (1.1) a (1.6) abc (1.7) ab (3.7) (1.1) a (1.2) a (2.2) abcd (2.9) bcd (3.9) (1.0) a (1.1) a (0.8) a (0.9) a (4.6) (4.1) b (3.2) cd (5.1) e (4.3) d (3.8) (3.2) b (2.9) bcd (3.7) de (3.1) bcd (4.9) (1.5) a (1.9) abc (1.4) ab (1.8) abc (3.6) (4.4) b (3.4) d (3.2) cd (3.6) cd F test NS ** ** ** * SEM ± (0.76) (0.56) (0.48) (0.59) (0.62) CD at P= (1.64) (1.40) (1.71) (1.81) DAT: Days After Treatment ; *: Significant at P=0.05 ; **: Significant at P=0.01 ; NS: Nonsignificant ; Figures in parantheses are x+0.5 transformed values ; Treatments with same alphabetical superscript within each column are statistically on par.

56 Table 11 : Evaluation of newer acaricides against yellow mite, Polyphagotarsonemus latus (eggs) infesting chilli at Karjagi, Haveri (Kharif 2007) II spray Treatments Dosage/ concentration Mineral oil 0.25% Mineral oil 0.50% Mineral oil 0.75% Mineral oil 1.00% Chlorfenapyr 10 EC Diafenthiuron 50 WP Fenazaquin 10 EC Milbemectin 1 EC Profenophos 50 EC Propargite 57 EC Dicofol 18.5 EC 75 g a.i./ha 375 g a.i./ha 125 g a.i./ha 3.75 g a.i./ha 190 g a.i./ha 570 g a.i./ha 2.5 ml/lit. Mean number of eggs per six leaves Second Spray 3 DAT 7 DAT 10 DAT 14 DAT (1.5) a (1.5) ab (0.9) a (0.7) a (1.9) a (2.6) bc (1.1) ab (1.0) ab (1.2) a (1.4) ab (1.2) ab (0.9) ab (1.2) a (0.9) a (0.7) a (0.9) ab (0.9) a (1.8) ab (1.1) ab (0.8) ab (1.1) a (1.1) a (1.5) ab (0.7) a (2.2) b (2.1) ab (2.2) abc (1.3) ab (1.9) a (0.9) a (0.9) a (0.8) ab (6.2) c (5.8) d (4.8) d (3.9) c (3.8) b (3.7) c (2.7) bc (3.5) c (1.6) a (1.4) ab (1.7) ab (1.3) ab Control Water spray (4.1) b (3.6) c (3.6) cd (1.6) b F test ** ** ** ** SEM ± (0.52) (0.48) (0.57) (0.30) CD at P=0.05 (1.51) (1.41) (1.66) (0.88) DAT: Days After Treatment ; **: Significant at P=0.01 ; Figures in parantheses are x+0.5 transformed values ; Treatments with same alphabetical superscript within each column are statistically on par.

57 Per cent reduction over control Mineral oil 0.25% Mineral oil 0.5% Mine ral oil 0.75 % Mine ral oil 1% Chlorfe na pyr Dia fenthiuron Fenazaquin Milbemectin Profenophos Propargite Dicofol Fig.1 : Bioefficacy of newer acaricides against eggs of yellow mite, Polyphagotarsonemus latus on chilli (I spray) Per cent reduction over control Mine ral oil 0.25% Mineral oil 0.5% Mineral oil 0.75 % Mineral oil 1% Chlorfenapyr Diafenthiuron Fenazaquin Milbemectin Profe nophos Propargite Dicofol Fig. 2 : Bioefficacy of newer acaricides against eggs of yellow mite, Polyphagotarsonemus latus on chilli (II spray)