Pathogenicity Study of the Local and Commercial EPNS Isolates Against the Third Instar Larvae of Cotton Leaf Worm Spodoptera Littoralis in Baghdad, Iraq

Abstract

Spodoptera littoralis larvae were collected from tomato fields in  al-usefiya region , Baghdad, Iraq. Bioassay was done to test the pathogenicity of EPNs  isolates against the third instar larvae of cotton leaf worm using three concentrations  100,150 ,200 ijs/ larvae. Results showed that best concentration was 200 ijs/ larvae . At 200 ijs/larvae higher mortality rates were recorded after 5 days of treatment table for native isolates Oscheius tipulae ,Oscheius myriophilis, Heterorhabditis bacteriophora  reached 93.00 , 92. 50 , 93.50 % respectively. While Cezar pesticide overcome on all isolates and recorded the highest mortality rate at 99.50% after 5 days of treatment. Oscheius tipulae isolate recorded less LC50 value reached 82.10 ijs/ larvae, While the commercial isolate Steinernema carpocapsae had LC50 value reached 125.77 ijs/larvae .