Seasonal incidence of major insect- pests and their biocontrol agents of soybean crop (Glycine max L. Merrill)

Abstract

The major insect-pests observed attacking soybean variety JS 335 were girdle beetle, Obereopsis brevis; tobacco caterpillar, Spodoptera litura; green semilooper, Chrysodeixis acuta; whitefly, Bemisia tabaci and jassids, Empoasca kerri. The peak activity of girdle beetle (1.0 damaged plant per meter row) was observed during first week of October. Whereas the peak activity of caterpillar pests that is, S. litura (2.5 larvae per meter row) and C. acuta (0.7 larvae per meter row) was recorded during second fortnight of August and that of sucking pests that is, B. tabaci (3.2 whiteflies per plant) and E. kerri (3.4 jassids per plant) was recorded during last week of August and Second week of August, respectively. The biocontrol agent's three species of lady bird beetle, Menochilus sexmaculata, Coccinella septumpunctata and Coccinella transversalis and orb weaver spider, Neoscona sp. were found predating mainly upon whiteflies and jassids. Whereas, lynx spider, Oxyopes sp. and a predatory pentatomid bug, Eocanthecona furcellata was noticed sucking the body sap of lepidopterous larvae. The peak activity of lady bird beetle in second week of August and September with 0.4 grub and adult per plant, whereas the predatory pentatomid bug and spider is both last week of August with 1.1 and 1.2 bugs and spider per plant respectively.