This page contains a Flash digital edition of a book.
Wasp attacks worsen


European PaperWasp themain villain as damage reported in orchards and vineyards.


By Scott Trudeau A


longtimewinery owner in Okanagan Falls says the European PaperWasp ravaged


his grapes last summer attacking his vineyards in record numbers. LarryGerelus, of Stag’sHollow


Winery and Vineyardwas surprised by the numbers ofwasps.Gerelus said he’s never seen anything close to it during the nearly two decades he’s been operating hiswinery. Gerelus first noticed thewasps among


hisMuscat grapes,which ripen earlier than others. “Oncewe knewitwas happeningwe


sawbasically the numbers build,” he said. “Normallywe don’t see that kind ofwasp pressure at all. Ifwe do see some it’s a non-issue.We have put traps out in the past but this year,we had to,


to try and capture asmany of thewasps aswe could.” In previous years, homemade traps


constructed fromtwo-litre pop bottles were placed among his PinotNoir grapes,where thewasps had been prevalent. “We’d catch a decent number,” he


said. “There’s alwayswasps around. The amount of damagewasn’t significant enough toworry about in the past.” Last summer,Gerelus said “it became worrisome”with regards to the volume


European Paper Wasp


ofwasps attacking his grapes and that there is “definitely a dollar value to the damage.” He began purchasing traps after


realizing they couldn’t keep up to the number ofwasps.He bought about a dozen traps but theyweren’t near enough to keep capturing the swarms landing on his grape clusters. When he returned to the store to


purchasemore theywere sold out. “So obviously the problemwaswidespread.” The attacks continued through


August and into September and October,with the greatest damage occurringMuscat, PinotNoir and Tempranillo varietals, compared to Merlot and Vidalwhich received far less damage. Horticultural consultantDuane


Holder said the European PaperWasps have been a problemsince about 2008. “The European PaperWasp has been


themost serious species that’s attacked cherries,” he said. “It became a problem for some of the orchards in the Creston area but also some of the orchards in theOkanagan have been affected by it —and I knowgrape growers have had issueswith it too.” Weather plays an important part in


the number of European PaperWasps. “The queens,when they emerge in


SCOTT TRUDEAU


Stag’s Hollow Winery and Vineyard in Okanagan Falls, shown here in mid-February, was attacked by the European Paper Wasp in record numbers last summer. Wasp traps were relatively ineffective at controlling the invader. Inset photo of grape bunch illustrates the high number of wasps that were responsible for destroying a significant number of grapes at Stag’s Hollow.


the spring, start to build nests and if spring conditions are fairlywarmthey get off to a good start,whereas if the conditions are cold andwet it probably inhibits their population growth a little bit,” saidHolder. “When you get into a hot, dry summer, especially an early seasonwhere they can go throughmore expansion of their population then they


British Columbia FRUIT GROWER • Spring 2014 21


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32