Zoller, A. M.

Zoller, Broc G.

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1. Thresholds and MonitoringBIASED SAMPLING OFCODLINGMOTH OVIPOSITION USING A CUTFRUITTECHNIQUE TO MONITOR MATING DISRUPTION IN BARTLETT PEARS.B. G. Zoller and A. M. ZollerThe Pear Doctor, Inc.P.O. Box 335Kelseyville, California 95451Keywords: codling moth, Cydia pomonella, pears, wound preference, ovipositionmonitoringAn oviposition-biased sampling method for detecting the presence ofmated femalecodling moths was utilized in pest management of1055 acres ofBartlett pears undergoingmating disruption in the BigValley area ofLake County, California. At39 to 18 daysbefore first harvest, intact fruit cluster samples (4.8 chisters/acre perweek) were inspectedatrandom for oviposition at 1050 -1800 degree days (88F/50F basis). They were pairedwith cluster samples containing a fruit wounded the previous week by removing a2-3 cmdiameter portion ofepidermis and fruit cortex to 0.5 -1 cm maximum depth. The cut fruitclusters were ateye level on the east sides oftrees. Anaverage of0.52 cut iruit/acre perweekwere inspected. Three cut fruit (0.29/acre) were located on 1sample tree near thecenter ofeach of107 ten acre sample areas and an average 2.4 cut fruit (0.23/acre) wereplaced inother locations ofthe sample areas thought to bepotential hot spots.Results and DiscussionCodling motheggs were observed in 2 (0.01%) of20,200 intact clusters examined vs21 (0.95%) of2212 wounded clusters examined 39 to18 days before first harvest Inconsidering the 1055 acres, this was a95-fold increase inthe detection ofoviposition usingthecut fruit technique. Inconsidering specific locations, oviposition was detected in9orchards encompassing 24 sample areas using thecut fruit technique. The mean detectionratio of cut/uncut fruit clusters diminished from >29at 39days before harvest to>8at 18days before harvest (Figure 1). It is interesting that the detection ratio value of>8wasreached about 1month earlier before harvest than inthe Sacramento Valley Bartlett pearcomparisons discussed inthecompanion abstract (Fig 2). This perhaps indicates an earlierrelease oftheattracting factors) from intact fruit inthe Big Valley area.In the 9 positive orchards, extra random inspections-of intact clusters wereperformed. Three ofthe orchards received extra preharvest organophosphate treatmentsbut control was below average. Ofthe 6untreated orchards, 5blocks achieved acceptablecontrol below 1% infestation. The remaining blockwas heavily infested along thesoutheast 1-5% ofthe orchard while the cut fruit and random intact cluster testing did notsample this problem area.Ofthe remaining 44 orchards (83 sample areas) with no positive cut fruit detectionofoviposition, 6minor peripheral hotspot infestations, 2major peripheral hotspotinfestations and1 fairly general 1.5% infestation were present at harvest.CUT vs UNCUT FRUITEGGS/100 FRUIT, BIG VALLEY35 32 28 25 21DAYS BEFOREBARTLETTHARVEST« CUTAJNCTJTBARTLETT, MEAN + MEAN ±STD ERROR— Y= 109.7-106X+0281X2;R2« LO; P= O01228CUT vs UNCUT FRUITEGGS/100 FRUIT, SACRAMENTOVALLEY21 14 7DAYS BEFORE BARTLETT HARVEST18 14+7CUTVSUNCUT BARTLETT .Y- 25.1+ 2.99X; R2- O907;P- O047

Biased sampling of codling moth oviposition using a cut fruit technique to monitor mating disruption in Bartlett pears

https://ir.library.oregonstate.edu/downloads/1r66j620g

Biased sampling of codling moth oviposition using a cut fruit technique to monitor mating disruption in Bartlett pears

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