Issue link: https://read.dmtmag.com/i/466321
www.goodfruit.com GOOD FRUIT GROWER MARCH 1, 2015 27 In recent years, scientists have applied new information about codling moth phenology to make mating disruption more effective. (See "Mating disruption tips.") Codling moth, which has successfully established itself in major apple produc- ing regions of the world, likely originated near Kazakhstan, home of the apple, he said. "It was likely spread along the silk trade routes and went wherever apples were sent." So it's not surprising that codling moth—coming from the desert climate of Central Asia—like it warm. Scientists have found that flying activity of male and female moths slows down and even stops when temperatures drop below 60°. "If they're not flying, that means there's no sexual activity," said Thomson, adding that more importantly, eggs are not as viable in cool, spring temperatures com- pared to the heat of summer. Spring temperatures also impact how fast codling moth populations build within an orchard. At warm temperatures, populations can double within 30 days, but at cool temperatures, it could take 90 days. "The lesson here is that during years with wet, cool springs, codling moth risk goes way down compared to those with warm, dry springs," he said. Thomson said that many researchers contributed through the years to codling moth biology. U.S. Department of Agriculture entomologist Dr. Alan Knight, based in Yakima, Washington, showed that as female moths age, their egg production drops. Dr. Vince Jones of Washington State University showed that at day one of a female moth's life, 50 percent of her eggs hatched, but at day six, only seven percent hatched. Scientists also noticed that codling moth like to aggregate within an orchard and create hot spots. Research showed that the more traps placed in orchards, the better. "More traps provide more information, especially in orchard 'hot spots' and allow growers to make better decisions," he said. Scientists have studied pheromones in the orchards but are not exactly sure how they work. Some think that the plume from pheromone dispensers creates a false trail, causing males to fly to the dis- penser instead of to females. Others say the pheromone masks the odor trail of female moths so that the males can't find them. Dr. Larry Gut, Michigan State University entomologist, found that "competitive attraction" plays an important role. Males follow the pheromone plume to the dis- penser and find the dispenser instead of a female, explained Thomson. The male olfactory sensors, while at the dispenser, become overloaded with scent and desensitized. Thomson noted that scientists have used titanium smoke to track the phero- mone plumes of passive and active phero- mone release dispensers. They've found that for passive dispens- ers, such as hand-applied ties, the size and reach of the plume stays the same regardless of the concentration of pher- omone in the dispenser. However, active pheromone aerosol dispensers work by creating a big burst of small particles (70 to 80 micron size) that travel long distances of 400 to 500 feet. What is known is that the pheromone plume makes it harder for males to find females and delays mating. When the males do find their target, the females are older and not as reproductive, all of which help keeps population num- bers lower. Thomson spoke during the annual meeting of the Washington State Horticultural Association. • 1-800-250-5024 • www.CertisUSA.com ©2015 Certis USA Recommendations: Cueva, Kocide Integrated copper solutions for season-long ÄYLISPNO[HUKZ\TTLY disease control Double Nickel )YVHKZWLJ[Y\TMVSPHY WV^KLY`TPSKL^HUK ÄYLISPNO[KPZLHZLJVU[YVS OSO FRAC 19 fungicide for Z\TTLYKPZLHZLZHUK WVZ[OHY]LZ[WYV[LJ[PVU CYD-X HP, Madex HP *VKSPUNTV[OHUK 6YPLU[HSMY\P[TV[O control PFR-97 )YVHKZWLJ[Y\T PUZLJ[PJPKLHUKTP[PJPKL Neemix 0UZLJ[NYV^[OYLN\SH[VY for psyllid control Deliver )[MVYSLHMYVSSLYSHY]HL control Screen Duo -VYZ\UI\YUWYV[LJ[PVU HUKOLH[Z[YLZZYLK\J[PVU Diseases and Pests: -PYLISPNO[ *VKSPUNTV[O6YPLU[HS MY\P[TV[O 7V^KLY`TPSKL^ 7Z`SSPKZHWOPKZTP[LZ leafrollers :\TTLYKPZLHZLZHUK WVZ[OHY]LZ[YV[Z ;OL )PVWLZ[PJPKL*VTWHU` Biopesticides. :OVY[9,0ZHUKaLYV KH`Z[VOHY]LZ[9LZPZ[HUJLHUK YLZPK\LTHUHNLTLU[(WWSPJH[PVU ÅL_PIPSP[`)L[[LYOHY]LZ[THUHNLTLU[ HUK[PTLS`ZOPWWPUN Screen Duo is a registered trademark of Crop Microclimate Management Inc. Cueva is a registered trademark W. Neudorff GmbH KG. Kocide is a registered trademark of Kocide LLC. All others are registered trademarks of Certis USA LLC. De PFR CX Ma Nx DN O Cu K2 K3 SD COURTESY WHITNEY CRANSHAW/CSU Codling moth prefer warm temperatures. Risk drops in years of wet, cool springs.