Start Date: Dec 02, 2005
End Date: Dec 01, 2010
1)Will combine systematic surveys of uncultivated and cultivated crop sites for reproductive hosts with manipulative field and lab experiments to test the ability of Frankliniella occidentalis to acquire Tomato Spotted Wilt Virus (TSWV) from weedy reproductive hosts and transmit it to crops. Because most thrips are transients in crop habitats, we will investigate the biotic-environmental factors underlying dispersal from weeds to crops and then determine how manipulation of certain weed reservoirs affect recruitment of viruliferous thrips into crops. Because a biological control agent, G. boliviana is available for tropical soda apple, this species is an excellent candidate to begin our examination of how herbivory from biological control agents affect other crop-herbivores and pest management issues. Success of this approach will provide impetus for future biological control programs for other weedy hosts of thrips and TSWV. 2) An inherent limitation of conservation biological control is overcoming the time lag between pest population increases and those of their natural enemies. Generalist predators may overcome this limitation by preying on nontarget prey. Orius insidiosus will serve as a model species for further investigation into relationships among non-crop plants, non-pest prey and predators of agricultural importance. 3) Will develop an effective monitoring system for adult C. cactorum by testing traps baited with the female sex pheromone and synthetic equivalents. A synthetic sex pheromone is currently under development by ARS. 4) Studies will be conducted to obtain information vital to modeling the spread and control of C. cactorum including: temperature influences on development, dispersal potential of C. cactorum and its potential North American Opuntia host-range. We will use mark-recapture trials to compare dispersal of sterile and fertile moths. Data will be incorporated into diffusion models using integro-difference equations to describe movement patterns. Data will also be used to construct life tables to estimate the effects of specific mortality factors such as SIT, biologicval control agents and host removal, on insect population dynamics.