The Efficacy of Metarhizium acridum Against Nymphs of the Italian Locust, Calliptamus italicus (L.) (Orthoptera: Acrididae) in Uzbekistan and Georgia

Trials with the naturally occurring fungus, Metarhizium acridum, were conducted against nymphs of the Italian locust, Calliptamus italicus, in Uzbekistan and in Georgia during 2010 and 2011. The trials were conducted in two quite different habitats: in western Uzbekistan, which is desert with a median annual rainfall of about 100 mm, and on the plains of Georgia, which receive about 400-800 mm of rain per year. In three trials at a dose of 500 mL/ha of Green Guard® (containing 50 g M. acridum spores/ha in oil) during 2010 in Uzbekistan, there were clear declines in locust numbers by 7 days reaching 69-76% by 14 days. During 2011, a dose of 500 mL/ ha resulted in a decline of 78% by 10 days and 90% by day 16, while at a dose of 250 mL/ha (containing 25 g M. acridum spores/ha in oil) declines were 69% and 71% by day 10 and 16, respectively. In Georgia, 8 trials were conducted at 500 mL/ha. At four sites in pastures during 2010, declines were evident by 7 days after treatment, reaching about 80% by day 14. With two applications against locusts in young sunflower crops, declines reached 66-83% by day 14. During 2011, at two sites with moderately dense pasture, locusts declined by 74% and 83% after 14 days. Overall, locust mortality was substantial in all of the trials even though the weather was quite hot, with maximum temperatures often near 40°C.