Prevalence of fungal entomopathogens in the life cycle of pear thrips, Taeniothrips inconsequens (Thysanoptera : Thripidae), in Vermont sugar maple forests

Few data are available on the occurrence of fungal infections in pear thrip s populations in sugar maple stands. Such studies are essential to the long -term development of fungi as effective biological control agents for pear thrips. Our goal was to determine the natural prevalence of infection at di fferent phases in the pear thrips' life cycle, while simultaneously recover ing new fungal isolates for possible use in a future control strategy. Samp ling thrips from four different sites in central Vermont, the developmental stages associated with the forest soil had the highest levels of infection compared with life stages found predominantly on foliage. The highest rate s were seen in larvae recovered from soil samples (11.9%), followed by adul ts collected from emergence traps and buds (5.9%) and larvae collected from the forest floor (3.9%). In contrast, 1.9% of the individuals sampled from the understory and 1.9% of the thrips collected from the upper canopy were infected. Further studies are needed to test and characterize these strain s and assess their potential for use in a pear thrips management program, ( C) 1999 Academic Press.