Emerging Pests of Bt Cotton and Dynamics of Insect Pests in Different Events of Bt Cotton

Transcription

1 Emerging Pests of Bt Cotton and Dynamics of Insect Pests in Different Events of Bt Cotton Udikeri.S.S., Kranthi.K.R 1., Patil.S.B.and Khadi.B.M Agricultural Research Station.Dharwad (Karnataka:India) 1 CICR,Nagpur (Maharastra:India) ssudikeri@gmail.com Abstract: Three different species of mirid bugs (Miridae : Hemiptera) viz., Creontiades biseratense (Distant), Compylomma livida (Reuter ) and Hyalopeplus linefer (Walker) are infesting cotton since Creontiades biseratense is most potential and widespread as key pest particularly in Karnataka state. Both adults and nymphs suck the sap from the base of square and tiny bolls leading to heavy shedding. Almost all cultivated Bt cotton genotypes found to be susceptible to mirid bugs. The minimum avoidable yield loss with two rounds of protection worked out was 20.6 %. Application of Acephate g.ai / ha is a good management option presently. Helopeltis bradyi (Waterhouse) is emerging as major pest in interspecific Bt cotton which has the history of causing cent per cent damage and yield loss. This paper also presents a new report of another insect pest flower bud maggot of cotton Dasirseura gossypii Fletcher. (Cecidomyiidae : Diptera). This insect has appeared as potential pest for the first time in the history of cotton entomology in India and elsewhere. Currently > 90 % fruiting body damage is has been recorded in largely cultivated Bt cotton cultivars viz Kanaka and Neeraj. The population dynamics of three boll worm species in different events of Bt cottons approved in India has been studied under unprotected conditions. Mon ( BG-II) contained all bollworms most effectively. 1. Introduction No other cultivated crop species so far reported is as susceptible as cotton to insect pests the world over. A complex of sucking pests and bollworms infesting throughout have made the cotton as intensive insecticide usage crop. The transgenic Bt cottons expressing Cry1Ac delta endotoxin became inevitable to solve the problem of insecticide resistance in bollworms and to reduce insecticide usage. With commercialization of Bt cottons for the first time in US and Australia in 1996, the changes in insect pest scenario was predicted owing to possible reduction in insecticide usage. These phenomena included the emergence of new pests preferably sap feeders and Cry1Ac resistant tissue

2 borers. Thus different species of mirid bugs have been considered as major production constraints for Bt cotton in Australia, China, US etc today. Since commercialization of Bt transgenic genotypes in 2002 there is miracle increase in area and production of cotton in India. During 2009/10 the area under cotton was lakh ha being highest in the world. With 295 lakh bales production the country remained second largest producer of seed cotton globally. The contribution form Bt cultivars is nearly 90 % which occupied 8.4 m ha area. Upto 69 % reduction in usage of pesticides has been achieved through Bt transgenic cottons. The reliance on synthetic pyrethroids and highly toxic broad spectrum organophosphate insecticides has been almost seized. Further commercialization of Bollgard-II (2006) cottons expressing Cry1 Ac and Cry 2 Ab together paved way for dominance of emerging pests in cotton. By 2010 six different Bt transgenic events have been approved for commercial cultivation in India. Hence there is mosaic of different hybrids and Bt genes offering varied level of resistance /susceptibility to bollworms and sucking pests. As a predicted phenomenon problem newly emerged pests has become significant issue in sustainability of Bt cottons in many countries. The incidence, spread and chemical control exercised over mealy bugs Phenacoccus solenopsis Tinsley (Pseudococcidae : Hemiptera) recently in India stands as land mark example for altered insect pest scenario. In South India and Maharastra state the mirid bugs (often referred as true bugs) are now creating havoc. Since its first appearance in 2005 (Patil et al., 2005) the incidence of Creontiades biseratense (Distant) is rampant. The present paper deals with status of mirid bugs and flower bud maggots as emerging pests as well as dynamics of key pests in different events of Bt of cotton in India. 2. Materials and Methods 2 a) Emerging pests Population dynamics and diversity of mirid bugs was assessed through regular survey in farmers fields in Karnataka state. The association of cultivars with mirid bugs was assessed by growing different Bt cottons (and non Bts as check) in two replicated randomized block design. The number of cultivars included varied in different years but they were tried at least for two consecutive seasons. Each genotype was grown in six rows under 90 cm X 60 cm spacing. No plant protection measures were offered to allow mirid bugs to invade the crop without any hindrances. Rest of husbandry was as per standards prevailing in University package of practices. Avoidable loss was assessed by protecting the crop twice in the peak mirid bug incidence period with different concentrations of most effective chemical Acephate 75 SP to create varied population. A similar study was conducted involving different insecticides and bio rationales to know best management option. In this study also only two rounds of treatment applications were maintained. All these studies have been carried out between 2007 to 2009 under rain fed conditions at Agricultural Research Station(ARS), Dharwad (Karnataka: India), which is situated between 15 07' N latitude and 76 06' E longitude with an altitude of 678 m above MSL in the northern transitional region (zone-8) of Karnataka (India). The average rainfall of ARS, Dharwad is mm. The mirid species under consideration was C. biseratense only for all these experiments as a dominant and regularly occurring species. The information from other states covered (if any) is based on personal communications with cotton entomologist under TMC /AICCIP projects. The bionomics and oviposition pattern of C.biserratnse discussed here is based on laboratory study conducted during 2009.The details are available in the publication Udikeri et al., (2010). The information on another mirid threat Helopeltis bradyi (Waterhouse) and a new pest flowerbud maggot are based on survey and strict vigilance over emerging pests in the state. Detailed observations have been carried out at ARS, Dharwad. 2 b) Dynamics of bollworms in different Bt cotton events The field experiment was carried out at ARS, Dharwad through involving intra specific Bt cotton hybrids of G. hirsutum. The care was taken to involve all commercially approved events of Bt transgenic technology in India. Thus five Bt cotton genotypes representing each approved events were involved along with a conventional (non Bt) check DHH-11. The observation were taken at 50, 75, 100, 125 and 135 (days after sowing) for the larval incidence of new world bollworm Helicoverpa armigera(hub) and spotted bollworm Earias vittella (Fab) on whole plant basis in ten randomly selected plants of each genotype. The damage to fruiting structure (squares/flowers/bolls) was also observed at the same time. The fruiting structures both intact and shed were taken into account to

3 workout the damage. Flower rosetting was observed at peak flowering for each genotype by counting the total number of flowers in ten plants and the number of rosetted flowers amongst them. Data was presented as per cent flower rosetting. For the incidence of pink bollworm larvae 20 green bolls were collected randomly and dissected carefully to the score incidence. 3. Results and Discussion 3 a) Emerging pests of Bt cotton: i) Species complex, distribution of mirid bugs and severity in India Three species of mirid bugs are found infesting cotton in India. None of these have been historically referred as key pests of cotton. It is only after enhanced cultivation of Bt cottons mirid bugs have assumed key status. Three different species of mirid bugs (Miridae : Hemiptera) viz., Creontiades biseratense (Distant), Compylomma livida (Reuter ) and Hyalopeplus linefer (Walker) are infesting cotton since Unlike widespread distribution of mealy bug Phenacoccous solenopsis Tinsley (Nagrare et al., 2009) the mirid bugs have been restricted to Central and South India. The dominant species is Creontiades biseratense (Distant).It is most potential, widespread and also becoming a production constraint every year( Plate 1 and 2). In Karnataka Creontiades biseratense mirid bugs are number one pests in presently followed by Tamila Nadu. Other states having menace of this pest are Maharastra and Andhra Pradesh. Compylomma livida (Reuter ) is dominant species in Maharastra however it is noticed in Karnataka also. Hyalopeplus linefer (Walker) is seen in Karnataka and Maharastra, but, not as regular pest. Its status is negligible. ii) Identifying characters The key mirid bug Creontiades biseratense appears in different colour morphs, brown and green being common. Black and red morphs are also often noticed. Such green and brown mirids are common Australia and US also. But they are colour morphs. In recent years, two species of mirid bugs were recorded in Australia, of which Green mirid (Creontiades dilutus) considered as a significant pest and brown mirid (C. pacificus) are quite common in pulse crops (Khan, 2004). Adult of Indian cotton mirid bug Creontiades biseratense are brown in color with dark brown T-shaped band on pronotum. Nymphs are greenish in color with dark brown wing pads. The characters of Megacoelum biserratense reported long from Thailand ( Hormachan et al., 1998) are similar to the Creontiades biseratense. Both could same also. Taxonomic revision is essential in this regard. Major identifying character of Hyalopeplus linefer is the presence of brownish parallel streaks on the pronotum. Distinct color morphs have been noticed in H. lineifer also. Nymphs of this species are creamish yellow in color with long antenna and wing pad. Both of these species are larger in size than Compylomma livida. The wing margins in these species are fringed and eyes are diaptic. iii) Nature of damage Both adults and nymphs damage developing flower buds/ squares and tender bolls. One to two days old bolls with dried petals intact provide a good habitat to the insects for feeding and sheltering. The characteristic symptoms of feeding on the flower bud shows oozing out of yellow fluid from the buds and staining of this yellow fluid on the inner surface of the bracts. Infested tender bolls have number of black patches on all sides of the outer surface of boll rind. It was observed shedding of most of the damaged squares and tender bolls. Usually the adults are swift fliers and brown in color. Nymphs are small with yellowish green abdomen and fast moving when disturbed. Feeding on matured bolls leads to parrot beaking and improper opening. It was estimated that damage leading to shedding of tender bolls for two days period revealed a loss of seed cotton yield. The symptoms of infestation and impact of mirid bugs observed in India do not deviate form the pestiferous cotton mirids described elsewhere. iv) Population dynamics and severity Population dynamics of mirid bugs has been assessed during 2007 to 2009 in Karnataka. Mirid populations ranged from (18 bugs/25 squares) to (66 bugs/ 25 squares) and reached their peak at all locations in September and continued until December. High population of mirid bugs were

4 recorded in Haveri (44 bugs/25 squares) and Belgaum district (43.8 bugs/25 squares). However, in Gulbarga the population was found to be low (18 bugs/25 squares). The severity of mirid bug incidence has been also noticed in Raichur and Bellary districts, however in Bidar, Bijapur, Gadag, Mandya and Uttar Kannada its incidence was low to moderate. But in all places irrespective cultivar it was regularly noticed (Fig 1). v) Cultivar association A total of 70 Bt and four conventional cotton hybrids were evaluated to asses host plant resistance to mirid bug C biseratense. Under repeated verification over three seasons none could show resistance to mirid bugs. Thus mirid attack was not genotype dependent, however slightly higher numbers on interspecific biotech hybrids. There was no significant difference among BG-I and BG-II, Non Bt and Bt hybrids also. Two cultivars viz., Kanak (MRC 7351) and Neeraj (MRC 7201) have always shown higher incidence of mirid bugs. These two hybrids have been much affected in farmers fields also (Table 1.) vi) Assessment of avoidable loss Two application of Acephate g ai /ha at peak incidence offered maximum protection against mirid bugs. The estimated loss was 449 Kg /ha or 18% over zero protection. This was on an average true with both BG-I or BG-II cultivars under moderate insect pressure. The could also be more if incidence is more or avoidable loss may increase with extended spray schedule. However two spay model could ideal considering the pest and damage potential nature (table 2). Vii) Management of mirid bugs Among various treatments, Acephate g/l was found be most significant treatment in reducing mirid infestation. Acephate could limit the mirid incidence to 14 bugs/25 squares against 46 bug in untreated control leading to maximum recorded seed cotton yield 3616Kg /ha. It was followed by Acetamiprid 20 SP and Imidacloprid 200SL. In Australia, recent trials have shown that reduced rate of Indaxacarb or Fipronyl combined with salt rendered effective control of mirid bugs (Khan, 2003). Fungal pathogens viz., Verticillium, Metahrhizium and Beauveria were not promising (Table 3). Viii) Bionomics of mirid bug C biseratense and oviposition pattern The females of mirid bugs C biseratense preferred to lay eggs in petiole where in 855 eggs were traced. There are five instars in the life history extending total life cycle upto days The details are available in Udikeri et al., (2010) (Table 4). 3 b) New report of Tea mosquito or Guava Kajji bug as pest of Bt cotton Helopeltis bryadi (Waterhouse) a hemipteran pest has been found damaging the Bt cottons severely. It is a common pest on Guava / Cashew/ tea etc. and are called kajji bug as it causes black lessons on the almost all leaves and young shoots, squares and bolls. However, it appears rarely on cotton crop, first time reported on DCH-32 cotton crop during 1996 in Honnali of Davangere district. Later in 2002, on the same genotype it was noticed in H. D. Kote taluka of Mysore district. The most severe damage of this pest insect was noticed on Bt cotton in Hosalli village of Uttar Kannada district. Affected genotypes are interspecific biotech hybrids. i) Nature of damage Both nymph and adults suck the sap from leaves and young shoots, squares and bolls. As a result of it leaves get rolled at the edge with brown central black lessons particularly near the main veins. Cankers like lesions develop on the lower green bolls. Linear scars with white papery layer appearance in tender shoots. Retarded growth leads to gradual dying of shoots. Matured bolls bear blackish brown circular pits towards tip of the bolls. Rottening of boll takes place due to entry of rainwater and such infested dried up bolls / squares remain intact in plant. 3 c) Flower bud maggot or gall midge of cotton: A new report. During 2009 severe incidence of gall midge Dasineura gossypii Fletcher, 1914 (Cecidomyiidae: Diptera) was seen in a farmer s field at Hesarur (Taluk : Savanur District : Haveri).

5 The crop was sown in first week June and by August incidence took severe proportions. Later in Kakol, Konanatambagi etc villages (Haveri District) also it has been noticed in severe form. In the research farm (ARS, Dharwad) it has been noticed in negligible proportions earlier, but, since couple of years its incidence is increasing. In Raichur, Bellary, Belgaum, Haveri, Gulburga and Dharwad district also the pest has been recorded during survey but, in low proportions. As the pest remains inside the flower and multiplies faster, it was difficult to manage this pest by the farmers even with 3-4 sprays. The insecticides used viz Imidacloprid (Confidor 200 SL), Oxydemeton methyl (Metasystox 25 EC), Monocrotophos (Monocil 40 SL), Acephate (Starthene 75 SP), Neem oil etc could not render satisfactory results. When these insecticides are used along with DDVP (Nuvan 78 EC) as tank mix 0.25 ml/l) the spread of incidence was checked to certain extent. In all the locations where the pest has caused wide spread damage the cultivar was MRC-7351 BG-II (Kanaka) only. In recent survey other hybrids have also shown varied degree of square damage ranging form 50 to 92 %. The yield loss attributed is more than 60%. i) History of the pest /previous reports Dasineura gossypii was described by Professor T. B. Fletcher in 1940 in Pusa, Bihar based on collections from cotton flower buds (Fletcher, 1916). From Tamil Nadu also (Coimbatore) it has been reported earlier as a pest on cotton as referred to as floral bud maggot (Ayyar 1932). Thus it could find a place in Cotton in India: A monograph Vol. II: 1960 (Dastur et al., 1960). After the initial reports, no single reference about its appearance as a major / minor pest is available. This is first ever in India Dasineura gossypii has seen as a major pest. ii) Nature of damage The maggots are damaging stages. They feed on anthers and stamenal column leading degradation / decaying. There will be 3-15 maggots in a flower bud. The infested flower buds fail to grow properly and they will not open as the petals as well as tissue inside dries. Thus comprehensive symptoms give a picture of flower drying through organ degradation and death. The pupation take place inside dried flowers it self. In general square formed will not turn into a boll, due to death at flowering stage. Tissue drying and/or death unevenly lead twisted or contorted stamenal column/ anthers. Compared to normal boll persistent stamina column is seen in affected ones but it needs confirmation. In some cases, where fertilization is not affected, the boll formation is affected. The size remains smaller. Tissue degradation is prominent on boll rind also. The bolls will not reach normal size and no proper filling with fibre. 3 d) Dynamics of bollworms in different events of Bt cotton: The incidence of E. vittella was noticed at later stage of the crop growth with higher population in DHH-11 (Non Bt) ie 3.2 and 4.1 larvae /plant) at 100 and 125 respectively. In rest, it was negligible or nil. Population of new world bollworm H. armigera was noticed by 50 itself in DHH-11 (1.8 larvae /plant). In Mon ( BG-II ) the incidence very much negligible. The rest had incidence more than one larvae per plant from 100 onwards (Fig 2). The fruiting body damage in all first generation Bt genotypes (Fig 3) ranged between 1.3 to 18.2 from 50 to 125. DHH-11 recorded highest damage (5 to 22.4 % ) from 50 till 125. The least fruiting damage was recorded in Chiranjeevi BG-II ( 0 to 1.2 %).The flower rosetting due to pink bollworm (Table-5) Pectinophora gossypiella ranged between 0.5 to 0.65 % in all events except BG-II in which (Chiranjeevi BG-II) 0.1% damage was noticed. The green boll incidence of PBW larvae was 0.4 to 0.7 per 20 bolls with no scores from BG- II event. The locule damage was highest among Bt events in Mom-531 ie 13.9 % with MLS-9124 very close to it. BG-II event also revealed 2.6 % locule damage though appeared free from pink bollworm activity in other observations. Conventional cotton had 23.2 locule damage due to higher incidence in green bolls 6.5 larvae/20 bolls) and 3.8 % flower rosetting. The dynamics of bollworms in different events could show far better suppression of all the three species in Mon (BG-II) event. However the efficacy of Cry 1 Ac as single gene (Mon-531 and event-1) was also justifiable even after eight years of Bt cotton cultivation in India. Higher incidence in conventional cotton could be taken as warrant regarding survival of bollworms and maintenance of biotic potential even under acute selection pressure of Bt toxins delivered through incorporated protestants. GFM fusion of Cry1 Ac+ Ab has proved worthy over Indian population of H.armigera like in China. The results of better efficacy of BG-I genotypes over non-bt, BG-II over

6 BG-I or/and non-bt have been justified form studies of Somashekara (2009),Udikeri(2006),Radhika et al., (2004),Vennila et al., (2004) Marchovsky et al., (2001) and Henneberry and Jech (2000). 4) Conclusions : Large scale cultivation of bollworm resistance Bt transgenic cottons have suppressed the dreaded pests successfully world wide. Significant reduction in usage of insecticide especially broad spectrum organophosphates and pyrethroids has given scope for emergence of new pests especially the sap feeders. Mirid bugs either prevailing hitherto or newer ones have assumed key status warranting couple of sprays during reproductions phase. Increased incidence of mirids in cotton may give rise to host range expansion as well as enhanced damage in alternate hosts of these pests. Key strategies and integrated approaches are essential for sustainable use of Bt technology. Diverse Bt events with ability to contain all bollworm species and other lepidopteran are ideal in Indian context. Acknowledgements: Indian Council of Agricultural Research (ICAR) New Delhi and Central Institute for Cotton Research (CICR) Nagpur are regarded for financial support for this research through TMC MM-I 3.1 project Emerging and key pests: their characterization, taxonomy, genetic diversity and control. Dr.C.A.Viraktamath. UAS. Bengaluru and Dr R.M.Sharma. ZSI. Jabalpur are acknowledged for taxonomic services. References Ayyar, J. V. R., 1932 Insects affecting the cotton plant in India. Madras Agril Dept Bulletin 28: Dastur, R. H., Asana, R. D., Sawhney, K., Sikka, S. M., Vasudeva, R. S., Quadiruddin, K. and Roa V. P., and Sethi, B. L., 1960 Indian Central Cotton Committee., Bombay Henneberry, T. J. and Jech, L. F., 2000, Seasonal pink bollworm, Pectinophora gossypiella (Saunders), infestation on transgenic and non-transgenic cottons. Southwestern Entomologist, 25 : Hormachan, P. A.,Wongpiyasatid and Piyapuntawanon 1998, New record of Megacoelum biseratense (Heteroptera: Hemiptera) in Thailand. Proceedings of KUDRI Research Conference, Khan, M Salt mixtures for mirid management. The Australian Cotton Grower 24 (3), 10. Khan, M., Kelly, D., Hickman, M., Mensah, R., Brier, H., and Wilson, L, 2004, Mirid ecology in Australian cotton. Marchovsky, R., Ellsworth, P. C., Moser, H. and Hennerberry, T. J., 2001, Bollgard and Bollgard II efficacy in near isogenic lines of DP50 upland cotton in Arizona. Arizona Cotton Rep., pp Nagrare, V. S., Kranthi, S., Biradar, V. K., Zade, N. N, Sangode, V., Kakde, G., Shukla, R.M., Shivare, D., Khadi, B. M., Kranthi, K. R., Widespread infestation of the exotic mealybug species, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae), on cotton in India. Bulletin of Entomological Research 99: Patil, B. V., Bheemanna, M., Patil, S. B., Udikeri, S. S., and Hosaman.i, 2006, A Record of mirid bug Creontiades biseratense (Distant)on cotton from Karnataka., India. Insect Environment. 11: Radhika, P., Sudhakar, K., Mohiddin, S. B. and Rao, G. M. V. P., 2004, Relative incidence of pest complex on Bt and non-bt cotton hybrids under protected and unprotected conditions. Int. Symp. Strategies for Sustainable Cotton Production-A Global Vision Vol. 3. Crop Prot., November 23-25, UAS, Dharwad, Karnataka (India) pp

7 Somashekara, R., 2009, Evaluation of first and second generation Bt cotton genotypes for characterization of resistance to bollworms and tobacco caterpillar. M. Sc. (Agri.) Thesis, Univ. Agric. Sci., Dharwad, Karnataka (India). Udikeri, S. S., 2006, Evaluation of new generation Bt cotton genotypes, Sustainability of Cry protein expression, computation of ETL, Effect on aphid predators and development of IPM module for Bt Cotton under rainfed conditions. Ph. D. Thesis, Univ. Agric. Sci., Dharwad, Karnataka (India). Udikeri, S. S., Kranthi, K. R., Patil, S. B., Modagi, S.A and Vandal, N.B Bionomics of mirid bug Creontiades biseratense (Distant) and oviposition pattern in Bt cotton, Karnataka Journal of Agricultural Sciences. 23(1): Vennila, S., Biradar, V. K., Gadpayle, J. G., Panchbhai, P. R., Ramteke, M. S., Deole, S. A. and Karanjakar, P. P., 2004, Field evaluation of Bt-transgenic cotton hybrids against sucking pests and bollworms. Indian Journal. Plant Protection., 32 (1) : Table 1: Bt cotton genotypes with comparatively low incidence of mirid bugs Cultivar group and Bt event HxB BG-I HxB BG-II HxB Non Bt hybrids Genotypes with less than average bugs per 25 squares ) NCHB 945,RCH-708 Nil DCH-32 N Bt, HxH BG-I NCS-145, BN Bt, RCH-2Bt, RCH-20Bt, NCS-954,NCS-929,Jk- ISHWAR,JK-DURGA, CHIRANJEEVI Bt, AKKA, DRUVA, NCS- 907 HxH BG-II NCS 145 BG-II, KCH 15, TULSI-9, TULSI 45, SP 1037, CHIRANJEEVI, JAI-BG-II, AKKA-BG-II, RCH-2, NCS-207 HxH Non Bt hybrids NCH 145, DHH-11 N Bt, Susceptible genotype KANAKA, NIRAJ Table 2: Incidence of mirid bugs under varied selection pressure and avoidable loss (Mean of three seasons) Treatments T1-Acephate 70SP T2-Acephate 70SP Dosage (gai.ha) No. of Mirid bugs/ 25 squares Ist spray 1DBS* 7* * (7.32) (7.57) (4.18) (3.96) IInd spray Mean No. of bolls/ plant Yield (kg/ha) Avoidable yield loss 1DBS 7 (kg/ha) (%) (6.58) (5.97) (4.71) (4.11) (5.86) (5.49) (6.29) (6.67)

8 T3-Acephate 70SP (7.21) 9.05 (3.17) (4.35) 6.70 (2.77) (4.48) (6.75) T4-Acephate 70SP (7.57) 3.55 (2.13) (3.72) 2.35 (1.83) (4.18) (6.89) q/ha 18 T5-Untreated control (7.30) (5.85) (8.58) (8.08) (8.22) (6.16) CV (%) SEm± Table 3: Management of mirid bugs through insecticides and biorationals (Pooled results of three seasons) Treatments Dose (per lit) *Thrips/ 3 leaves *Jassids/ 3 leaves *Mirid bugs /25 squres *Coccinelli ds/plant Yield (kg/ ha) T1- Dimethoate 30 EC 1.7ml (4.02) 2.95 (1.94) (5.63) 0.85 (1.33) T2-Imidacloprid 200SL 0.2 ml (3.36) 2.70 (1.79) (4.85) 0.55 (1.23) T3-Acetamiprid 20 SP 0.2 g 7.40 (2.89) 1.40 (1.54) (4.48) 0.85 (1.30) T4-Thiamethoxam 25 WG 0.25 g (3.40) 2.22 (1.79) (5.59) 1.70 (1.62) T5-Acephate 70 SP 1.0 g 16.80(4.21) 4.10 (2.25) (3.87) 2.40 (1.84) T6-Chlorpyryphos 20 EC 2.0 ml (4.49) 4.05 (2.24) (5.91) 2.66 (1.91) T7-Neem oil + Nirma powder 2.5ml +1.0g 20.10(4.59) 4.10 (2.26) (5.42) 5.15 (2.48) T8-Nirma powder 10.0g (6.30) 9.50 (3.24) (6.71) 3.65 (2.15) T9-Verticillium leccani 2.0g (4.65) 7.05 (2.83) (6.45) 4.40 (2.32) T10-Beauveria bassiana 2.0g (5.26) 5.60 (2.56) (6.40) 4.15 (2.26) CD (5%) SEm± Table 4: Biological parameters of and morphometric measurements of mirid bug C.biseratense Stage Mean±SD Length(mm) Mean±SD Breadth(mm) Mean±SD Egg (Incubation period) Days 5.60± ± ±6.9 Nymphal duration (Days) I instar 2.69± ± ±2.7 II instar 2.76± ± ±0.15 III instar 2.83± ± ±2.4 IV instar 2.89± ± ±1.6

9 V instar 2.83± ± ±0.25 Total nymphal period (Days) 14± Pre mating period 1.75± Mating period 3.60± Pre oviposition 2.51± Oviposition 9.51± Post oviposition 8.22± Fecundity (Number of eggs) 15.0± Adult longevity (Days) Male 13.20± ± ±9.8 Female 21.0± ± ±0.15 Adult life cycle (Days) Male 41.13± Female 39.94± Table 5: Incidence and damage due to pink bollworm Pectinophora gossypiella in different Bt cotton genotypes Genotypes Bt toxin Events JKCH 99 Cry1 Ac Event-1 Tulasi 4 Bt Cry1 Ac MON-531 Chiranjeevi BG-II Cry1 Ac + Cry2 Ab MON DHH 11 Non-Bt Non Bt Flower resetting (%) Larvae per 20 green bolls Locule damage (%) Nathbaba Cry1 Ab + Cry1 Ac (Cry1 A) GMF event

10 MH-5125 Cry 1C MLS

11 Seasonal mean Seasonal dynamics Plate 1: Adult of mirid bug Creontiades biseratense Gulbarga Haveri JUL AUG SEPT OCT Forthnight/Month NOV 2FN 1FN 2FN 1FN 2FN 1FN 2FN 1FN 2FN 1FN 2FN Belgaum DEC Miridbug/25 Squares 45 1FN Mirid bugs/25 squares Plate 2: Nymph of mirid bug Creontiades biseratense Miridbug/25 Squares Gulbarga Haveri Districts Fig 1.Seasonal dynamics of mirid bugs in Karnataka Belgaum

12 (Average of 2007,2008 and 2009) 6 JKCH 99 (Event -1) Tulasi 4 Bt (MON- 531) Chiranjeevi BG-II (Mon-15985) DHH 11 (non Bt) 1 Nathbaba (GFM ) 0 Ha 50 Ha 75 Ha 100 EV 100 Ha 125 EV 125 Ha 135 MH-5125 (Metahelix) Fig 2. Larval incidence of Helicoverpa armigera and Earias vittella