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Lene Jakobsen, Michael Brogaard, Annie Enkegaard, Henrik F. Brødsgaard and Jesper M. Aaslyng

Dynamic climate regimes have been developed mainly to reduce energy consumption in the greenhouse, and this has been the main reason for their adoption by growers. During recent years, Danish growers have observed that problems with pests have diminished since they changed from the traditional rigid climate regime to a dynamic regime. The trend has also been observed in scientific experiments testing different dynamic climate regimes. The present experiment shows that the influx of thrips from outside into the greenhouse was reduced by 40% under a dynamic climate regime compared to a traditional rigid regime, and that this was related to the opening degree of the vents. Vents were open on average 7% under the dynamic regime and 33% in the traditional climate. The influx of thrips was linearly correlated with density outside the greenhouse (P < 0.0001) and with opening degree of the vents (P = 0.0001).

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Steve L. Brown and James E. Brown

In each of 3 years, the average number of thrips in tomato (Lycopersicon esculentum L. cv. Mountain Pride) blooms was greater on tomatoes grown on white plastic mulch than on tomatoes grown on black plastic mulch, aluminum plastic mulch, or bare ground. Early season differences, however, diminished with time as plants grew and shaded a larger portion of plastic mulch. Weekly applications of 12 insecticide treatments failed to reduce thrips populations below that found in the control. No significant differences were found among treatments in the quantity, quality, or earliness of tomato yields. Incidence of tomato spotted wilt (vectored by some thrips species) was too low to detect statistical differences or determine the importance of thrips population in disease epidemiology. Western flower thrips (Frankliniella occidentalis) was the most common species found, followed by eastern flower thrips (F. tritici) and tobacco thrips (F. fusca). Thrips control, in the absence of tomato spotted wilt, is not justified for the thrips populations encountered in this study.

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Meredith R. Blumthal, L. Art Spomer, Daniel F. Warnock and Raymond A. Cloyd

California at Davis supplied western flower thrips. This research was made possible by a grant from the UIUC Campus Research Board (RES BRD CLOYD R 1-2-68037) awarded to Raymond A. Cloyd and Daniel F. Warnock. We also thank Jack Juvik, Department of Natural

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Raymond A. Cloyd and Amy L. Raudenbush

primary pest. Western flower thrips are extremely polyphagous, feeding on a wide range of greenhouse-grown horticultural crops ( Gerin et al., 1994 ; Lewis, 1997 ; Tommasini and Maini, 1995 ). Western flower thrips populations are a major concern of

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Yinping Li, Raymond A. Cloyd and Nora M. Bello

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important insect pest of greenhouse-grown horticultural crops worldwide ( Cloyd, 2009 ; Kirk, 2002 ; Lewis, 1997a ; Reitz, 2009 ; Robb and Parrella

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Christopher S. Cramer, Narinder Singh, Neel Kamal and Hanu R. Pappu

Colorado during 2003 was estimated to have cost growers $2.5 to $5.0 million in farm receipts alone (Schwartz and Gent, unpublished data). The virus is spread by onion thrips ( Thrips tabaci L.). If the rate of spread and damage from IYS and onion thrips

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Raymond A. Cloyd and Joshua D. Gillespie

Western flower thrips are the most destructive insect pest of greenhouses worldwide, causing both direct and indirect damage to a wide range of horticultural crops ( Brodsgaard, 1989 ; Gerin et al., 1994 ; Helyer et al., 1995 ; Tommasini and

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Rebecca L. Loughner, Daniel F. Warnock and Raymond A. Cloyd

Foundation. The authors would like to thank Stephanie Larsen and Andreana Lau for their assistance with this research and David A. Nickle, USDA Systematic Entomology Laboratory, Beltsville, Md., for the identification of thrips species used in this project

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Steven T. Koike, Frank G. Zalom and Kirk D. Larson

information on distinguishing these categories has been published ( University of California, 2008 ). Type I bronzing ( Fig. 1A ) results from arthropod feeding, most commonly by western flower thrips ( Frankliniella occidentalis Pergrande) or cyclamen mite

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Steven J. Damon, Russell L. Groves and Michael J. Havey

Onion thrips is an important insect pest of onion causing direct damage to leaves and stored bulbs ( Alston and Drost, 2008 ), reduced bulb and seed yields ( Elmore, 1949 ; Jones et al., 1934 ), and transmission of serious pathogens such as iris