Efficacy of Newer Insecticides against Pod Borer Complex of Pigeonpea and Screening of Pigeonpea Genotypes for Helicoverpa Resistance

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Date
2001-05
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Entomology Department, N. M. College of Agriculture Gujarat Agricultural University, Navsari
Abstract
Field efficacy of some new chemical insecticides viz., profenofos. carbosulfan, imidacJoprid, lamda-cyhalothrin, Polytrin-C, Nurelle-D, Spark along with endosulfan against pod borer was tested at College Farm, N.M. College of Agricullure, Gujaral Agricultural University, Navsari during kharifseason 1999. The treatment of profenofos 0.075 per cent when applied at 50 per cent flowering and anolher two sprays at 15 days interval. it out performed all the insecticides in exhibiting ovicidal (H. armigera eggs) and larvicidal action (H. armigera and plume moth larvae). Carbosulfan, Nurelle-D, Spark, imidacJoprid and lamdacyhalolhrin also showed good ovicidal action on H. armigera eggs. Profenofos also remained most effective in checking the pod damage to green pods by all the three pod borers. Nurelle-D remained second to profenofos in checking HelicoVt'rpa damage and was comparable with Spark, imidacloprid and PolytrinC. The plume molh damage was also effectively checked by Polytrin-C, Spark, lamda-cyhalothrin and Nurelle-D. When the efficacy of insecticides was judged on the basis of damage inflicted by pod borer complex (Helicoverpa + plume moth + pod fly) and their different combinations (Helicoverpa + plume moth. Helicov<',pa + pod fly, plume moth + pod fly) 10 the pods, treatment of prof en of os again: remained superior and equally effective to that of lamda-cyhalothrin. Polytrin-C also gave good control of above combinations of borers. As far as sucking pesbviz., aphids and thrips~~oncemed. all the insecticides were found etfective in checking aphid popUlation. however. imidac\oprid found better for controlling aphids. whereas. none of the insecticide' proved effective for controlling thrips popUlation. The insecticides also evaluated for their toxic effect on natural enemies. Only endosulfan proved safer for conserving the chrysopa population. So far the economical aspect is concerned. the treatment of lamdacyhalothrin (NICBR. I :7.10) found most economical followed by profenoros. Polytrin-C, Spark. Nurelle-D and endosulfan. The field trial conducted at the Pulse Research Station. G.A.U .• Navsari during kharif 1999 to screen out the pigeonpea genotypes against Helicov<'Ipa incidence under LSVT (Large Scale Varietal Trial) indicated that entry ICI'L-87 I 19. OT-17 and BP-8758 showed less ovipositional preference to HelicoV<'lpa as compared to other genotypes viz., GAUT-9212. BP-9402. OT-9. GAUT-9317. however. entry GAUT-9212 was preferred most for egg laying. Though the Helicoverpa larval population in 14 genotypes showed non-significant difference, the lowest pod damage (24.20%) was found in the entry GAUT-9111. however. it was susceptible along with other four entries GAUT-8625. GAUT- 9212, GA UT -9402 and OT -17. The other varieties were found highly susceptible. At harvcsC"'~ the varietal reaction to Helicoverpa in case of GAUT-8625 and GAUT-9212 changed lTom susceptible to tolerant. whereas. in case of OT-9, it changed from highly susceptible to susceptible. The response against plume moth indicated that two varieties (GAUT-8625 and ICPL-871(9) showed tolerant reaction. whereas. rest of the varieties showed less susceptible (BP-9402, GAUT-X630, GAUT-93 17), susceptible (GAUT-8824. GAUT-93 17. BI'-9403, BP-9401. GAUT-92 12, OT-9) and highly susceptible (BON-2, GAUT-9111. BP-875X) reaction. In case of pod fly BDN-2 and GAUT-8625 showed tolerant reaction. whereas. other varieties found less susceptible (BP-9403, GAUT-8630, GAUT-93 17, GAUT-911I, DT-9, BP-9402), susceptible (BP-940I, BP-8758, GAUT-92 I 2, ICPL-87119) and highly susceptible (GAUT-8824, DT-17). 111 Similar screening under A VT (Advance Varietal Trial) revealed non-significant difference among the genotypes viz., 99N-82, 99N-84, 99N-86, 99N -87. 99N -88, BDN-2 in response to Helicoverpa eggs, larvae and percentage pod damage. All the varieties found highly susceptible to Helicoverpa, however, the genotypes screened against plume moth, only 99N -88 showed tolerant and other genotypes showed susceptible reaction against plume moth. In case of pod fly damage to pod, three entries (99N-87, 99N-86 and 99N-82) found less susceptible, whereas, rest of the entries found susceptible (BDN-2) to highly susceptible (99N-84 and 99N-88). The investigation also made on the influence of some pigeonpea plant characters on pod borer inddence indicated that under LSVT, number of seeds pel' pod and 100 seed weight had positive and significant correlation with Helicoverpa oviposition and larval density. The time of 80 per cent maturity had Significant and positive relation with plume moth damage to pod. When plant character of A VT pigeonpea varieties were correlated, only 80 per cent maturity showed negative and significant correlation with Helicoverpa larval population. The efficacy of B.I. was "r ' ..• tested under laboratory condition by adopting bioassay method. The LC,o of B.t.. against 3'd - instar Helicoverpa larvae was 0.023148 per cent with fiducial limits of 0.023137 and 0.705903 with regression equation, Y=4.63 1575 + 1.010712 x. The effect of B.I. survival larvae on some growth parametel'/"'~' also observed. It indicated that with the increasing concentration, the development period of both the immature stages (larva and pupa) w. .. i increased, whereas, weight of both the immature stages, pupation rate and adult emergence w .. !l decreased. There was reduction in fecundity in the adult emerged from pupae, when the larvae fed with B.I. treated sunflower leaves compared to fed on untreated leaves.
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SAHANE UTTAM GANPAT_32611