International Journal of Plant Protection

S. G. Khorasiya ¹, H. J. Vyas ¹, D. M. Jetha ¹, P. H. Joshi ¹

Affiliations
1 Department of Entomology, College of Agriculture, Junagadh Agricultural University, Junagarh (gujarat), IN

Abstract

A field experiment was conducted to determine the efficacy of different insecticides against gram pod borer, Helicoverpa armigera (Hübner) Hardwick infesting pigeonpea at Junagadh Agricultural University campus, Junagadh during Kharif-Rabi season of 2006-07. The results revealed that indoxacarb 0.007 per cent, spinosad 0.005 per cent and emamectine benzoate 0.005 per cent were found to be the most effective in reducing the gram pod borer population. The highest yield was also recorded in the treatment of indoxacarb 0.007 per cent (1658 kg/ ha) followed by spinosad 0.005 per cent (1582 kg/ha) and emamectine benzoate 0.005 per cent (1494 kg/ha). The treatment of indoxacarb 0.007 per cent was found most economical as it gave the highest cost benefit ratio (1:7.546) followed by endosulfan 0.07 per cent (1: 6.766), cypermetrin 0.006 per cent (1: 5.492), novaluron 0.01 per cent (1: 5.376). Considering the overall efficacy, yield and economics of different insecticides, two sprays of indoxacarb 0.007 per cent, endosulfan 0.07 per cent, cypermetrin 0.006 per cent, novaluron 0.01 per cent can be recommend for effective and economical control of gram pod borer infesting pigeonpea.

Keywords

Pigeonpea, Helicoverpa Armigera, Field Efficacy

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S. G. Khorasiya ¹, H. J. Vyas ¹, D. M. Jetha ¹, P. H. Joshi ¹

Affiliations
1 Department of Entomology, College of Agriculture, Junagadh Agricultural University, Junagarh (gujarat), IN

Abstract

Studies on biometrical analysis were carried out at Junagadh Agricultural University campus, Junagadh (Gujarat) during 2006-07 to test the applicability of Dyar’s law to the larvae of H. armigera, when reared on pigeonpea variety BDN-2 at a constant temperature of 28±1°C in BOD incubator. The measurements of head capsule width of the larvae fell into six well defined groups each indicating an instar. The mean values of the observed (0.285 to 2.657 mm) and calculated head capsule width (0.287 to 2.819 mm) and progression factors were closed to each other which indicated that an increase in head width during successive instar was in geometrical progression, when larvae were reared on pigeonpea and it followed the Dyar’s law. The observed mean body length and width ranged from 1.712 to 28.378 mm and 0.306 to 3.643, respectively, for first to six instars on pigeonpea. The observed and estimated progression factors for the larval body length and width passed through six instars were 1.77 and 1.75 and 1.66 and 1.63, respectively. The progression factors determined from body length and width indicated the great deviation to provide any support for the theory suggested by Przibram’s and Megusar law. The multiple correlation co-efficient (R2=0.9996) also indicated a very high predictability of head capsule width through larval body length and width.

Keywords

Helicoverpa Armigera, Biometrical Analysis, Pigeonpea

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