Natural enemy (Arthropoda-Insecta) biodiversity in vegetable crops in Northeastern Tamil Nadu, India

Natural enemies of insect pests in vegetable crops (brinjal, okra and tomato) were recorded and their diversity was studied in Kancheepuram and Tiruvallur Districts, Tamil Nadu. Natural enemies were collected by pitfall traps, sweeping nets and by hand picking from January 2011 to December 2013 twice in a month. Totally 129 species of predatory and parasitic insects were recorded. All the natural enemies were grouped into 50 families under eight different orders. Order hymenoptera contained the highest number of families and species. Among the predators, Coccinellidae (ladybird beetles) was found to be the dominant group with high number of species. It was clear that Coccinellidae, Staphylinidae, Carabidae and Pentatomidae were the predominant natural enemies throughout the study period. In 2013, formicidae formed the major family of occurrence from July to December in the vegetable fields; in this period the total number of individuals collected from all families was the highest. The maximum Shannon-Wiener diversity index was 3.70 during the second season in 2013. Maximum richness (5.99) was recorded in the second season of 2012. The variations in the diversity, species richness and evenness between two cropping systems are discussed in this paper