THE INFLUENCE OF CLIMATIC FACTORS ON THE FLIGHT ACTIVITY OF THE JAPANESE-BEETLE (COLEOPTERA, SCARABAEIDAE) - IMPLICATIONS FOR USE OF A MICROBIAL CONTROL AGENT

The effects of meteorological parameters on flight activity of the Jap anese beetle, Popillia japonica, on Terceira Island, Azores, Portugal were studied using an Omnidata portable weather station and Japanese b eetle traps baited with the floral attractant, phenethyl propionate an d eugenol (3:7). In the absence of inclement weather, flight toward an attractant source occurred throughout the day with an activity peak b etween 1300 and 1500 h. Cloud cover that reduced solar radiation below 0.6 Langleys (Ly)/min and wind velocity above 20 km/h markedly reduce d flight activity. Average climatic conditions during the time of maxi mum attraction to baited traps were temperature of 25.5-degrees-C, lit tle or no cloud cover with light intensity of 1.1 Ly/min, relative hum idity of 59.4%, and wind of 12.9 km/h. Changes in weather from optimal conditions for flight of the beetle to those that inhibit flight can be abrupt and occur often on Terceira. The influence of meteorological factors on beetle behavior indicates that applications of microbial a nd conventional insecticides would be most effective if made during cl imatic conditions that encourage aggregations of beetles on host plant s and at other attractive locations. Because conventional insecticidal applications against adult beetles appear to be of limited value on T erceira, the use of entomopathogenic fungi for the microbial control o f P. japonica may provide a viable alternative for suppressing this pe st. Metarhizium anisopliae, especially in combination with attractive traps, appears to offer good potential for control of P. japonica. A 4 - to 5-day delay in onset of mortality of adult beetles that were expo sed to a lethal concentration of M. anisopliae spores allows sufficien t time for dissemination of the fungus by beetles. The infected adults could then serve to create new foci of infection for larval P. japoni ca. (C) 1994 Academic Press, Inc.