DIFFERENTIAL EFFICACIES OF NOMURAEA RILEYI AND ISARIA FUMOSOROSEA ON SOME SERIOUS PESTS AND THE PESTS' EFFICIENT PREDATOR PREVAILING IN TOMATO FIELDS IN EGYPT

摘要

The efficiency of the two microbial control agents Nomuraea rileyi and Isaria fumosorosea, were evaluated against Bemisia tabaci and Myzus persicae pests in tomato cultivations The safety levels of the agents, to the predator Coccinella undecimpunctata, were also studied under laboratory and field conditions. Results showed that under laboratory conditions, LC_(50) values for N, rileyi and I. fumosorosea were 103.7xl0~4 and 139.4xl0~4 spores/ml against B. tabaci, respectively, while the correspondingvalues for M. persicae were 89.1xl0~4 and 149.8xl0~4 spores/ml, respectively. Under the field conditions, the percentages of infested plants with B. tabaci and M. persicae were significantly decreased after treatments with both fungi as compared with the corresponding controls. At the El-Esraa farm (Nobaria region), the weights of the tomato yield were 2,417 and 2,911 kg/feddan when I. fumosorosea and N. rileyi were applied respectively, as compared with 2,010 kg/feddan in the corresponding controls. The corresponding yields in El-Kassaseen were 2,699 and 2,999 kg/feddan, respectively, as compared to 1,990 kg/feddan in the control. The present study showed that C. undecimpunctata exhibit relatively high and reasonable resistance to N. rileyi and I. fumosorosea at the highest lethal concentration (1x10~8 spores/ml) for both tested preys.