Efficacy of Selected Granular Insecticides for the Control of Maize-Stem Borer (Chilo partellus) (Lepidoptera: Pyralidae)

Abstract

Stem borer (Chilo partellus) is the most destructive pest of maize causing considerable yield losses especially during yala season. At present the pest is managed through whorl application of insecticide granules or foliar spraying of liquid formulations of insecticides. However, effective control of the pest cannot be expected from liquid formulations due to practical difficulties in the spraying especially at the mature stages of the crop. Hence, investigations were carried out in two consecutive yala seasons in 2008 and 2009 to study the efficacy of granular type insecticides against the stem borer. The maize hybrid variety Sampath was used. Four insecticides were tested along with an untreated control. Insecticides were applied twice as whorl applications at 2 week interval. The percentage stem borer damage in plots treated with Diazinon 5G, Fipronil 0.3G and Thiocyclam hydrogen oxalate 4G found to be < 8% as compared to > 35% damage in untreated control. Larval population and severity of stem borer damage were also significantly low in Diazinon 5G, Fipronil 0.3G and Thiocyclam hydrogen oxalate 4G treated plots during both seasons over the control. The percentage seed yield in Diazinon 5G, Fipronil 0.3G and Thiocyclam hydrogen oxalate 4G treated plots found to be 52-91% and 28-44% higher than the untreated control during yala 2008 and 2009 respectively. Therefore, Fipronil 0.3G and Thiocyclam hydrogen oxalate 0.4G can be recommended in addition to the present recommendation of Diazinon 5G for the control of stem borer in maize.

Interactions Among Bt Maize, Entomopathogens, and Rootworm Species (Coleoptera: Chrysomelidae) in the Field: Effects on Survival, Yield, and Root Injury

“…The Þlter cake of microsclerotia and diatomaceous earth produced from this process was broken into small pieces and air dried to a moisture content of Յ5%, (yielding 900 Ð1,000 granules/g). Granules were applied at a rate of 45 kg/ha, which is approximately double typical rates that are used for granular insecticides in maize systems (i.e., Lance and Sutter 1990, Kakar et al 2003, Gunewardena and Madugalla 2011. We applied the granules at this higher rate because the procedure for producing microsclerotial granules is relatively new (Jackson and Jaronski 2009), and baseline rates for the use of M. brunneum microsclerotial granules in the Þeld have not yet been established for management of rootworm species.…”