BIOEFFICACY OF Bacillus thuringiensis ISOLATES AGAINST SPOTTED POD BORER, Maruca testulalis (Geyer) ON COWPEA (Vigna unguiculata L.)
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Date
2004
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AAU, Anand
Abstract
Studies on bioefficacy of native Bacillus thuringiensis (Berliner) isolates (TOM-1, TOB-1 and CT-2) in laboratory, pot as well as field conditions against Mamca testulalis (Geyer) on cowpea variety pusa falguni were carried out at Gujarat Agriculture University, Anand campus during Kharif 2002 and 2003. Bioassay study of B. thuringiensis isolates (TOM-1, TOB-1 and CT-2) against M. testulalis indicated that significant larval mortality was started after 48 hrs. of application and it was increase with increased in concentration and exposure period. The isolate B.t. TOB-1 gave highest larval mortality (83.33 %) at 144 hrs. followed by B.t. CT-2 and B.t. TOB-1 which exhibited highest mortality (80.00% and 76.67%) respectively, after 144 hrs. at 10 power 9 spore crystal mixture/ ml. Thus the bioassay of three native isolates showed substantial efficacy and scope for effective suppression of M. testulalis. The bioefficacy of three B.t. isolates along with treated and untreated checks carried out against M testulalis in pots under net house conditions exhibited that larval mortality was numerically better in B.t. TOM-1 (80.00%) followed by B.t. CT-2 (72.00%) and B.t. TOB-1 (66.00%). All the treatments remained significantly superior over control. Field experiment conducted for two years showed that different treatments effectively reduced the pest population, flower damage and pod damage in order as University recommended practices followed by Delfm, 5.^T0M-1, B.t. CT-2 and B.t. TOB-1. The highest pod yield was also recorded in University recommended practices followed by Delfin, which was found at par with B.t. TOM-1, B.t. CT-2 and B.t. TOB-1. All three native B.t. isolates were able to check the population of M. testulalis and reduced the flower and pod damage and ultimately gave economic yield over control.
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AGRICULTURAL ENTOMOLOGY, AGRICULTURE, BIOEFFICACY