Relative toxicity of neem to natural enemies associated with the chickpea ecosystem: a case study

Abstract

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.

Integrated Pest Management (IPM) for Reducing Pesticide Residues in Crops and Natural Resources

“…Observations on the effects of various treatments on soil inhabiting natural enemies at vegetative phase revealed that plots treated with endosulfan had significantly lower populations (107.7 trap −1 ) with 64 % reduction compared to the control (302.3 trap −1 ). The plots treated with HNPV showed minimum disturbance to natural enemies with a catch of 267.1 trap −1 , on par with the control (Ranga Rao et al 2008).…”

“…In the present IPM module, the use of neem during the vegetative phase, followed by the application of Helicoverpa Nucleo Polyhedrosis virus (HNPV), a popular insect pathogen at flowering and needbased application of chitin inhibitors (novaluron, flufenoxuron) instead of conventional insecticide (endosulfan) during pod formation phase in pest management would be of immense help in augmenting the natural enemies in the chickpea ecosystem (Ranga Rao et al 2008). …”

“…The overall effect of endosulfan, neem, and HNPV indicated 52, 29, and 14 % reduction in population of aerial natural enemies, respectively, over control. (Ranga Rao et al 2008) Effect of IPM options on larval parasitoids of H. armigera. During the study period, the larval parasitization of H. armigera was mainly by Campoletis chlorideae.…”

Safety Studies of DpNPV (Diaphania pulverulentalis Nuclearpolyhedrosis Virus) Suspension and its Formulation on Non-Target Organisms in Mulberry Ecosystem

“…HaNPV@ 250 LE ha -1 application on chickpea resulted in a reduction of aerial and soil inhabiting natural enemies by 15 and 22 per cent respectively, over the control plots, while the reduction in the endosulfan sprayed plots was 52.4 and 63.1 per cent, respectively (Ranga Rao et al, 2008).…”

Interactions Between Two Invertebrate Pathogens: An Endophytic Fungus and an Externally Applied Bacterium

“…Among the leguminous crops chickpea (Cicer arietinum L.) is an important, nutritive and inexpensive crop among the people of the developing world (Sharma et al, 2007). Moreover chickpea plays a key role in increasing soil fertility through biological nitrogen fixation (Rao et al, 2008). From sowing to maturity a number of insect pests attack chickpea plants.…”