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WineEast cooler northeastern states such as New York, Pennsylvania and Michigan, where this pest is known to affect both wine and juice grape varieties. Much of the past research has been aimed at determining the best time to apply insecticides to tar- get eggs and larvae. Researchers in those states have developed degree-day (DD) models that use either a fixed calendar date or a "biofix" date (such as bloom of native grapevines) to determine the start- ing point to accumulate DDs. Degree-days are most commonly cal- culated for GBM by using a minimum temperature threshold or "base tempera- ture" of 47.1°F (8.41°C) developed by researchers at Penn State.4 Daily DD accumulation is calculated by averaging the daily high and low temperatures and subtracting the base temperature. Grow- ers are encouraged to record DDs from the biofix date until harvest. One or more methods are utilized by growers to predict GBM activity in the vineyard. If the grower wishes to apply an insecticide to treat the first generation of moths, he or she can predict the emer- gence by the capture of male moths in sticky traps containing the sex pheromone of the female GBM. The eggs that are deposited on berry clusters are also a useful indicator of a new generation increasing in population. However, the eggs are small (about 1mm in diameter), transparent and very difficult to In the Texas Gulf Coast region, the first male moths (above) are trapped as early as April. detect by the untrained eye. Berry infesta- tion is a bit easier to see, although it is best to treat the potential problem before berry infestation occurs. EasternWineLab_Mar09.qxp 1/22/09 9:47 AM Page 1 Due to these factors, growers often use a combination of DD predictions and physical trap catch data to determine when the emerging generation is entering vineyards in the spring and estimate the peak populations of successive genera- tions. For example, the suggested range of DD from 50% bloom of the wild grape Vitis riparia to the peak in egg laying by EASTERN WINE LABS Serving the Analytical needs of East Coast Wineries WWW.EASTERNWINELABS.COM Ph 609-859-4302 Cell 609-668-2854 chemist@easternwinelabs.com AOAC Member Your Source for Quality Label Printing Award Winning Custom Pressure-Sensitive Labels Digital • UV Flexo • Letterpress • Foil Stamping Paper & Film Stocks • "Ice Bucket" Labels Luminescent Effects on Foil & Silver Film Stocks UV Coating • Lamination 2 Witte Lane, Great Meadows, New Jersey 07838 Office: 908.637.8188 • Fax: 908.637.8189 • Cell: 908.963.7703 Email: classicimpressions@embarqmail.com Website: www.classicimpressionsco.com WINES & VINES NOVEMBER 2012 107 the second generation of GBM is about 810 DD in New York.5 But is the second generation a major target for insecticides in Texas? The protocols developed in cooler climates offer a useful starting point for growers to develop management programs in hot climates such as Texas. However, the extremes in temperature must be taken into consideration when estimations of GBM activity are predicted. Laboratory work by researchers at Penn State University established an upper threshold of 93.2°F (34°C) for activity of eggs and larvae.4 For example, temperatures rarely are greater than 93°F for long stretches of time in the northeastern United States, but it is not uncommon to experience temperatures higher than 93°F for more than 15 days per month during the latter part of the growing season in Texas (June-August.) This may result in significant decreases in the severity of infestations in hotter versus cooler years in Texas, which grow- ers could translate into increased savings of insecticide treatments during hot sum- mer months. Texas research A 2007-09 field study conducted by Texas A&M Extension and Research in five com- mercial vineyards in the Texas Gulf Coast region showed that the first emerging male moths are trapped as early as late April,