Biological Control 37 (2006) 186–195 www.elsevier.com/locate/ybcon 1049-9644/$ - see front matter  2005 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2005.09.020 InXuences of impatiens pollen and exposure to Beauveria bassiana on bionomics of western Xower thrips Frankliniella occidentalis Todd A. Ugine a,¤ , Stephen P. Wraight b , John P. Sanderson a a Department of Entomology, Cornell University, Ithaca, NY 14853, USA b USDA-ARS, US Plant, Soil, and Nutrition Laboratory, Ithaca, NY 14853, USA Received 8 July 2005; accepted 22 September 2005 Available online 4 November 2005 Abstract Adult female western Xower thrips, Frankliniella occidentalis, were exposed for 24 h to impatiens leaf disks treated with Beauveria bassiana at low and high application rates (ca. 100 and 1000 viable conidia/mm 2 ) and subsequently maintained on impatiens leaf disks supplemented or not supplemented with impatiens pollen. OVspring production and mortality of insects were monitored daily. Exposure to B. bassiana at the low and high rates signiWcantly reduced thrips longevity by 3.9 and 4.0 days, reduced the ovipositional period by 3.4 and 3.0 days, and reduced lifetime fecundity by 22 and 46% at the low and high rates, respectively. Infection by B. bassiana resulted in a sublethal (pre-mortem) eVect on oVspring production, decreasing oVspring production on the day before death by 1.2 oVspring/female. Pollen supplements had no eVect on adult female thrips longevity, yet did signiWcantly increase both daily (2.3 and 3.8 times) and lifetime fecundity (2.1 and 3.6 times) compared to control insects in tests at the low and high rates, respectively. No signiWcant Beauveria £ pollen interactions were detected at the low rate; however, a marginally signiWcant pollen £ B. bassiana interaction was present in tests of both daily and lifetime fecundity. There was a signiWcant eVect of B. bassiana on lifetime oVspring production in the presence of pollen, but the eVect was not detectable in the no pol- len treatment. The increase in both daily and lifetime oVspring production in the presence of pollen and the slow action of B. bassiana suggest that if B. bassiana is to be used successfully as a thrips management tool in impatiens crops, it must be applied before pollen becomes present and targeted against thrips immature stages to kill the insects before they reach reproductive maturity.  2005 Elsevier Inc. All rights reserved. Keywords: Western Xower thrips; Frankliniella occidentalis; Bionomics; Pollen; Fecundity; Entomopathogenic fungus; Beauveria bassiana 1. Introduction Western Xower thrips (WFT), Frankliniella occidentalis (Pergande), is a key pest of greenhouse vegetable and orna- mental crops around the world. Direct damage is caused when thrips feed on Xower buds, leaves, and fruit. Indirect damage is caused by the transmission of plant tospoviruses, vectored by thrips (Daughtery et al., 1997). Thrips damage to ornamental and food crops can be unsightly and lower the aesthetic appeal, and thus value of the crop. To combat thrips, growers typically use chemical insecticides (both synthetic and biorational). Application of certain chemical insecticides can quickly achieve successful thrips manage- ment (often within 1 day), compared to biological control agents whose Wrst eVects are often not detectable for several days. The low cost of traditional insecticides and their ease of use make these management options attractive. How- ever, WFT has demonstrated a strong capacity to resist chemical insecticides (Herron et al., 1996; Immaraju et al., 1992; Zhao et al., 1994), and research on alternative man- agement options is being pursued. Among the alternatives under investigation are insect pathogens. Thrips, which feed on plant cell contents using piercing/sucking mouthparts, are not highly susceptible to pathogens that invade per os. Thus, fungi, which infect by penetrating directly through the insect integument, are the most promising microbial biocontrol agents for these insects. * Corresponding author. E-mail address: tau2@cornell.edu (T.A. Ugine).