Neem products are often perceived as harmless to natural enemies, pollinators and other non-target organisms. For this reason, several integrated pest management (IPM) programmes have adopted neem as one of the prime components. This study revealed toxic effects of neem on soil-inhabiting and aerial natural enemies in chickpea to an extent of 41 and 29% population reduction, respectively, compared with 63 and 51% when using a conventional insecticide (endosulfan). Neem also affected the parasitization of Helicoverpa armigera (Hü bner) larvae by Campoletis chlorideae Uchida up to 20%. The natural enemy population started building up from the vegetative phase and reached their peak during the reproductive phase, and there was a gradual decline from pod formation to pre-harvest phases of the crop. Adapting the currently used IPM system in chickpea using neem during the vegetative phase, followed by an application of Helicoverpa nuclear polyhedrosis virus (HNPV) at flowering and need-based application(s) of chitin inhibitors like novaluron or flufenoxuron instead of endosulfan during pod formation would strongly augment natural enemy populations. This paper discusses the relative toxicity of neem and other IPM components on soil-inhabiting and aerial natural enemies in the chickpea ecosystem.
Seasonal abundance of tea mosquito bug, Helopeltis antonii infesting neem was studied at weekly intervals between May 2019 and April 2020 by direct counting at Forest College and Research Institute, Mettupalayam. After the northeast monsoon shower ceased, the population of tea mosquito bug started infesting neem during October-November, 2019. The bugs were active in neem until April, 2020 at varied levels of intensity and the pest population reached its peak during January, 2020. The highest number of tea mosquito bugs was recorded (9.60 per three terminal shoots per tree) during the third standard week of 2020 and the lowest numbers were recorded during 15 th standard week of 2020 (2.00 per three terminal shoots per tree). Wind velocity and maximum temperature (Tmax) were found to be negatively correlated with the population of tea mosquito bugs with the R-values of -0.632 and -0.493 and were found to be statistically significant at 1 per cent level. Rainfall and relative humidity were also found to be negatively correlated with r values of -0.159 and -0.086, respectively. Similarly, sunshine hours and evaporation rates were also negatively correlated with r values of -0.187 and -0.048, respectively. While, the minimum temperature (Tmin) was positively correlated with the population abundance of tea mosquito bug with the r value of 0.099.
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