PRODUCTION AND FIELD-EVALUATION OF A GRANULOSIS-VIRUS FOR CONTROL OF SESAMIA-CRETICA LED. (LEP., NOCTUIDAE) IN MAIZE FIELDS IN EGYPT

Pilot field trials were conducted against Sesamia cretica Led. using a Granulosis Virus recently isolated from the corn borer infesting maiz e at Kafr El-Sheikh Governorate. The efficacy of spray application of ScGV was compared with the currently recommended chemical insecticides (Methomyl and Monocrotophos) as two different control strategies agai nst S. cretica larvae on maize. The viral insecticide is a highly puri fied suspension of granules in water plus 10% molasses as a sticker as well as a feeding stimulant additive. The spray containing 0.1 g of g ranules/l (i.e. 1.48 x 10(10) I.B./ml) was applied twice at the rate o f 1.25 and 2.51/0.01 feddan (1 feddan = 4200 m(2)) at 2 week intervals , starting 3 weeks after sowing. For the chemical insecticides, the me thomyl was applied at the same time as the ScGV suspension against S. cretica larvae, and the monocrotophos was applice twice, 2 months afte r sowing, and 2 weeks later, against Ostrinia nubilalis and Chilo agam emnon larvae. All treatments were made using a portable knapsack spray er. Additional plots were left as control. Results revealed that both tested treatments (microbial and chemical insecticides) noticeably red uced the numbers of S. cretica larvae. Regarding yield, the mean weigh t of seeds was higher for the plots which were treated with either vir us or insecticide than untreated ones. However, the chemical insectici de treatment was more effective than the formulated virus treatment. T he corrected yield in ardab (1 ardab = 145 kg)/feddan were 20.11, 16.0 4 and 12.79, for chemical insecticide, viral insecticide and control t reatments, respectively. It is concluded that ScGV seems to be pathoge nic to the field population of S. cretica and may be considered a prom ising biocontrol agent to support the Integrated Pest Management Progr amme of such an important corn borer.