numerous ornamental and even weeds.

Transcription

1 The fungi belonging to order Erysiphales and family Erysiphaceae are commonly known as powdery mildew fungi. The fungi are highly pathogenic to the variety of Angiospermic plants causing disease powdery mildew. The fungi grown ecto parasitically on the surface of the infected plant parts. The superficial mycelium of the fungi produces enormous number of conidia usually on the leaf surfaces, which appear like a mass of white powder, hence the name powdery mildew. As a group, powdery mildew fungi infect many species of plants, including many trees, shrubs, crops, vegetables, cereals, grasses, numerous ornamental and even weeds. It is clear from the literature that nearly 7187 host species which are all Angiosperms spread all over the globe are attacked by powdery mildew fungi. Powdery mildew is more common on cultivated plants and grows luxuriantly in dry, cool seasons. Depending upon environmental conditions the powdery mildew disease may cause significant destruction and loss in plants and yields. With the onset of summer they began to disappear and the plants become free from the infection during scorching heat and rainy season. 165

2 In the present research work studies are mainly carried out on the survey, biochemical changes and ecofriendly management of powdery mildew of cucurbits. An extensive visits were carried out to different localities in the field of Jalgaon Dist. at Khandesh region of Maharashtra state. Similarly repeated visits were made continuously in every season at every place from 2004, 2005 upto In this visits details survey and observation were carried out about time of incidence of powdery mildew and to capture the stage of disease development. In an extensive survey; a detail studies about symptomological work, etiology and morphological features of causal organism at the conidial stage and both conidial and ascocarp stages are carried out. In addition to this physiological changes in host plant, biochemical changes in infected host were also studied. Similarly work has been carried out for the ecofriendly control of the powdery mildew on cucurbits by using botanical; plants and animals bioproducts. In the survey it is observed that cucurbits where cultivated in both kharif and rabbi season (table 1 and 2). The Kharif crop is cultivated In June July which shows occurrence of powdery mildew in October-November whereas the rabbi crop is cultivated November-December every year. Cucurbits like Cucurbita maxima, Langeria siceraria, Cucurbita pepo, Luffa acutangula and Luffa cylindrica where highly infected. This survey clearly indicate that the occurrence of powdery mildew is mainly related with the physical factor. Atmospheric temperature, relative humidity and 166

3 duration of sunlight place of vital role in the disease development (Somani et. al., 1976) reported occurrence of powdery mildew during July to September. Sharma and Jain (1974), observed on some host disease incidence was reported during month of march. Khosala et. al., (1988) observed powdery mildew from August to September. The incidence of powdery mildew on cultivated and wild crop were reported with the disease development. Dastur (1921) noted that conidial germination was best at 97 to 100% relative humidity. Where as Dixon (1981) reported that powdery mildew of cucurbits develops better in shade than in the full sunlight. It was observed in survey that maximum occurrence of powdery mildew is mainly on the leaves and young stem (table 3 to 6), the basal leaf infected more than the top leaf. The incidence of the disease is more between flowering stage to fruiting stage of the crop. Similar type of observation was reported by earlier by Mujal and Kapoor (1973); Sharma and Chaudhari (1980), Goswami and Dasgupta (1981), Verm (1981), Singh (2000) and Pawar (2005). Experiment was carried out in the laboratory with different solution for conidial germination (Table 10). It was observed that glucose solution fever the conidial germination in all the cucurbit. This clearly suggest that sporangial germination needs certain external stimuli for the improvement in the germination process. Mandge (1998) reported that glucose solution fever the sporangial germination of Albugo candida. However the effective 167

4 of chemical on sporangial germination of obligate fungi in the literature is lacking. The result regarding of hypersensitive reaction lesion due to powdery mildew infection war very common in Cucurbita pepo, Cucurbita maxima, Langeneria Siceraria, Luffa acutangula and Luffa cylindrica (table 12). This clearly indicates that cucurbit crop might be having resistant genes against powdery mildew and there fore such genes if they are to be introduced in the cultivated crops may be a good alternative for approaching powdery mildew disease management of the crops. Singh and Reddy (1996) also observed water melon bud necrosis. Singh and Verma (2005) observed hypersensive reaction in some cultivated Vigna species, cultivated from Maharashtra. The occurrence of powdery mildew on cucurbits causes several biochemical changes in the host plant. The results regarding the biochemical changes (Table 17 to 19). Clearly indicated that infected leaves showed loss in dry weight due to infection of Sphaerotheca fuliginea. Chlorophyll contain in the infected leaves of cucurbit showed significantly decrease similarly loss in nitrogen and protein contain was observe in the infection leaves of Citrullus fistulosus, Cucurbita pepo, Luffa cylindrica and Momordica charantica. Diener (1963) reported decrease in total chlorophyll in the infected leaves was considerable which may be due to enhanced activity of chlorophyllase or may be due to inhibition of the 168

5 pigment. This decrease in chlorophyll a/b ratio may be mainly due to marked decrease in chlorophyll a and chlorophyll b was affected slightly. Results regarding biochemical changes like reducing sugars found to decrease in the infected host except Cucumis sativus, Cucurbit pepo and Luffa cylindrica (Table 20 to 23). This appears that the Sphaerotheca fuliginea might have induced the production of soluble sugars which are metabolized by the growth of pathogen. Similarly Citrullus fistulosus shows loss in ash content due to infection of Erysiphe cichoracearum. It is interesting to note that calcium contain increase significant due to infection of powdery mildew. Whereas phosphorus contain decrease in the infected cucurbits similar type of observation recorded by workers. O Brien (1948), Walker and Weber (1949), Phillip and Ballantyne (1963), Conover (1957), Stone (1959), Dekkar ( ), Anon (1965), Misiga (1966), Sohin and Nayar (1969), Khan et. al., (1971), Sirdhana and Chaudhari (1972), Besada (1972), Sharma (1973), Akram et. al., (1978), El-Ammaria (1983), Kaur and Jhooty (1985), Cohen et. al., (1990). Thin et. al., (1996), Bharat (2003). Crude fat contain in infected leaves of Citrullus fistulosus and Luffa acutangula is decrease considerably whereas crude fiber is found to be increase in all the cucurbits due to infection of Erysiphe cichoracearum and Sphaerotheca fuliginea (Table 24 to 27). Similarly nitrogen free extract decrease and total carbohydrate is also found to decrease in the infected leaves of cucurbits. 169

6 During the past three decades crop production has been greatly influenced by the dramatic increase in the use of pesticides. Indeed, these compounds have played an externally important role in obtaining the maximal yield potential of almost every commercial crop by reducing yield losses caused by plant pathogens and other pests. However, due to indiscriminate and excessive use of these potentially hazardous, chemicals, several environmental threat and health problems to mankind and liver stock s etc. have arisen. Intensive use of chemical fertilizers and pesticides combined with poor management of water shades has resulted in severe water stress, pesticides contamination of water and agricultural products in addition to unacceptable degradation of soil, resulting in disruption of ecosystem over large areas. Pesticide contamination of food, water reservoirs and soil, has become a fact of life. An attempt have been made for the ecofriendly management of powdery mildew by using botanical, plants and animal bi-product. Aqueous leaf extract with five different concentration were applied directly in the field against the growth of powdery mildew (Table 28 to 38). It is found that Neem leaf at 15% concentration, Parthenium leaf extract with ten percent concentration Ocimum and Citrus leaf extract at 20% concentration, Annona leaf extract at 10% concentration, Ipomea leaf extract at 15% and Jowar leaf extract at 20% concentration is proved to be beneficial for the partial or complete suppression of powdery mildew development. Similarly Cow urine at 20% concentration. Ash spray at 15% concentration and 170

7 Butter milk at 20% concentration is found to be successfully dose for the management of disease (Table 35 to 37). Ghewande (1987) studied effect of extracts of Azadirachta indica, Lawsonia alba, Pongamia glabra and Tridex procumbens, along with fungicides for the control of the late leaf spot (Phaeoisariopsis personata) and rust (Puccinia arachidis) diseases of groundnut crop. Whereas, Shetty et. al., (1989) reported the leaf and fruit extracts of Azadirachta indica were useful in the control of Trichoconiella padwickii the seed-borne fungus in paddy. Khan and Kumar (1990) found that the leaf extract of Azadirachta indica checked thee seed mycoflora of wheat. Tewari and Nayak (1991) used leaf extracts of 4 plant species viz., Piper betle, Ocimum sanctum, Nyctanthes arbotritis and Citrus limon were effective in reducing the radial in vitro growth of Pyricularia oryzae, Cochiliobolus miyabeanus and Rhizoctonia solani. While, Datar and Qureshi (1991) found that the leaf extract of Polyalthia longifolia was most effective in reducing mycelial growth of Curvularia lunata, which was followed by Parthenium hyesterophorus, Eucalyptus citriodora, Punica granatum, Tabernaemontana coronaria, Calotropis procera and Ipomea carnea and bulb extract of Allium cepa was more active than Allium sativum. Varshney (2001) recorded that diluted Azadirachta indica and Tagets erecta leaf extracts found more antifungal than Lantana camera, Pinus roxburghii against stripe disease of barley caused by Dreschlera gramineae. 171

8 Hiwale and Kamble (2004) used 10% leaf extract of Salvia aegyptiaca L., Melia azaderach L., Ocimum sanctum L., in the management of fruit rot of Cucumis sativus as biopesticides. Devi and Jadhav (2005) studied the effect of neem and Parthenium leaf extract in combination with chemicals (2, 4-D and BHC) for the control of sugary diseases of Sorghum. When the result regarding the use of botanical at 10 to 25%. Concentration was found to be beneficial for the partial or a complete growth of powdery mildew. a combination of aqueous leaf extract of Neem, Parthenium, Ocimum, Citrus, Annona, Ipomea and Jowar, along with cow urine, Butter Milk and plant product Ash is use to prepared a biological product name as Dashparni ark Table 38. An aqueous extract of Dashparni ark spray on the cucurbits successfully control the powdery mildew of cucurbits. This product may be recommended to the farmer to control the powdery mildew disease. As powdery mildews know to control by using systematic fungicides attempt have been made to control this disease by using different fungicide at different concentration Table 39 to 43. It was interesting to note that fungicide like Bavistine, soluble Sulpher Calixin, Karathane and Salamon at 15% concentration successfully control the growth of Erysiphe cichoracearum and Sphaerotheca fuliginea. This clearly gives in idea that the fungicide along with plant leaf extract help together for the integrated and eco-friendly management of powdery mildew of cucurbits. Similar type of work was carried out early by (Sen and Kapoor, 1924) use Karathane to 172

9 control the powdery mildew of cucurbit. Waraitch et. al., (1975) for the control the of powdery mildew of bitter gourd. Bandopadhyay et. al., (1980) reported that Karanthane is use to control powdery mildew on different cucurbitaceous plant. Bhatia and Thakur (1989) use the best control of Sphaerotheca fuliginea on bottle gourd (Lagenaria siceraria), Musk melon and Pumpkin was given by 1-2 sprays of Calixin, Bavistin and Sulfur. Tripathi et. al., (1995) the efficacy of Karathane, Wettable sulfur, Calixin and Bavistin to control powdery mildew (Sphaerotheca fuliginea) on bottle gourd and Lagenaria siceraria. Recently Pawar (2005) made an attempt to achieve control of powdery mildew with the spraying of fungicides and plant extracts which proved to be beneficial for the partial or complete suppression of powdery mildew development. This clearly gives an idea that the fungicides and plant extracts together or separately can be used for the better management of powdery mildew disease. 173