Impact of Thiamethoxam 12.6% + Lambda Cyhalothrin 9.5% Zc on Population of Lady Bird Beetles in Maize Crop Ecosystem

A field experiment was conducted at Agricultural Research Station, Anand Agricultural University, Derol, Dist. Panchamahal, Gujarat, India during kharif 2011 and 2012 to study the impact of application of insecticide on population of Coccinellids [Cheilomenes sexmaculatus (Fabricius) and Coccinella septempunctata (Linnaeus)] in maize crop ecosystem. In the present study, three doses (22, 27.5 and 33 g a.i./ha) of ready mix formulation of thiamethoxam 12.6% +lambdacyhalothrin 9.5% ZC (Alika 247 ZC) as well as thiamethoxam 25 WG @ 25 g a.i./ha, lambda cyhalothrin 4.9 CS @ 15 g a.i./ha, carbofuran 3 G @ 1000 g a.i./ha and dimethoate 30 EC @ 350 g a.i./ha along with control were evaluated. All insecticides, except carbofuran, were appliedas foliar sprayson 30 and 45 days after sowing, whereas carbofuran was applied into soil at the time of sowing in furrows. All the three doses of ready mix formulation of thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC and thiamethoxam 25 WG @ 25 g a.i./ha as well as dimethoate 30 EC @ 350 g a.i./ha reduced the population of Coccinellids in maize crop. Lambda cyhalothrin 4.9 CS @ 15 g a.i./ha and carbofuran 3 G @ 1000 g a.i./ha did not adversely affect Coccinellid population. The maximum population of Coccinellids was observed in untreated control. In the present experiment, it could not be determined that the adverse impact of insecticides on Coccinellidpopulation was due their direct toxicity to Coccinellids or indirect affect through reduction in host population or both.