Behavior of bio- and chemical insecticides in tomato ecosystem in Minia Governorate

Abstract

Influence of certain insecticides, ie. emamectin benzoate, acetamiprid, indoxacarb, and two bio-agents; entomopathogenic nematode Heterorhabditis bacteriophora (EKB20) and Bacillus thuringiensis (Bt); in alternating the organization of entomophagous and their biological agents complexes were studied in tomato ecosystem in Minia Governorate, Egypt. The results reflected the tendency of entomopathogenic nematode and B. thuringiensis for selectivity, followed by emamectin benzoate when compared with the other insecticides. Diversity indexes after application of entomopathogenic nematode, emamectin benzoate and B. thuringiensis were higher at the two applications in the two successive seasons, followed by indoxacarb and acetamiprid. The highest values of equitability were shown in the treatment of entomopathogenic nematode and B. thuringiensis until 10 days post-treatment. The results showed that EKB20, Bt and emamectin benzoate have highly toxic effect against Spodoptera littoralis and Tuta absoluta with low effect on the beneficial insects in tomato. The difference can be attributed to different mode of action of product and number of sprays. Therefore, emamectin benzoate, EKB20, and Bt are considered good promised control elements, especially in successful release of some schemes of tomato integrated control.