Production and field evaluation of a Granulosis Virus for control of Sesamia cretica Led. (Lep., Noctuidae) in maize fields in Egypt

Abstract

AbstractPilot field trials were conducted against Sesamia cretica Led. using a Granulosis Virus recently isolated from the corn borer infesting maize 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 against S. cretica larvae on maize. The viral insecticide is a highly purified 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 granules/1 (i.e. 1.48 × 1010I.B./ml) was applied twice at the rate of 1.25 and 2.5 1/0.01 feddan (1 feddan = 4200 m2) at 2 week intervals, starting 3 weeks after sowing. For the chemical insecticides, the methomyl was applied at the same time as the ScGV suspension against S. cretica larvae, and the monocrotophos was applice twice, 2 months after sowing, and 2 weeks later, against Ostrinia nubilalis and Chilo agamemnon larvae. All treatments were made using a portable knapsack sprayer. Additional plots were left as control. Results revealed that both tested treatments (microbial and chemical insecticides) noticeably reduced the numbers of S. cretica larvae. Regarding yield, the mean weight of seeds was higher for the plots which were treated with either virus or insecticide than untreated ones. However, the chemical insecticide treatment was more effective than the formulated virus treatment. The corrected yield in ardab (1 ardab = 145 kg)/feddan were 20.11, 16.04 and 12.79, for chemical insecticide, viral insecticide and control treatments, respectively. It is concluded that ScGV seems to be pathogenic to the field population of S. cretica and may be considered a promising biocontrol agent to support the Integrated Pest Management Programme of such an important corn borer.