JULY 31 UI PSYLLID/ZEBRA CHIP UPDATE

Published online: Aug 06, 2012 Insecticide, Fungicide
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A new potato alert was posted to PNWPestAlert.net.

"University of Idaho potato psyllid scouting update - 31 July 2012

"Potato psyllid captures were down slightly for the week of 23 July. We are reporting the first detection of potato psyllids in Gooding and Bonneville Counties, and the first report of liberibacter-positive psyllids in Canyon and Minidoka Counties this year.

"From the University of Idaho sampling network, we collected the following from sticky cards last week: 1 psyllid from one site in Gooding County; 2 psyllids from one site in Minidoka County; 3 psyllids from one site in Bonneville County; 8 psyllids from one site in Jerome County; 9 psyllids from one site in Twin Falls County; and 2 psyllids from the Kimberly R&E center (in Twin Falls County).

"Crop consultants and growers submitted the following on yellow sticky cards: 6 psyllids from 3 different sites in Elmore County; 3 psyllids from 2 sites in Canyon County; and 1 psyllid from a non-commercial site in Payette County.

"From sticky card samples that were collected during the week of 16 July, 3 of 7 psyllids tested positive for liberibacter from one Twin Falls County site; 3 of 4 psyllids tested positive from another Twin Falls County site; 3 of 8 psyllids tested positive from the Kimberly R&E Center, and 2 of 6 psyllids tested positive from one Jerome County site. The one psyllid collected from a vacuum sample at a Twin Falls County site tested positive. In addition, psyllids on sticky cards (bulk sampled by location) submitted by crop consultants from fields in Minidoka, Elmore, and Canyon Counties tested positive for liberibacter.

"The following is a brief summary of potato psyllid findings on sticky cards to date in Idaho:

University of Idaho sampling network:

"Twin Falls County (3 sites, including Kimberly R&E Center) - adult psyllids (some positive for liberibacter); zebra chip infected plants confirmed (2 sites, including Kimberly R&E Center);

"Jerome County (2 sites) - adult psyllids (some positive for liberibacter at one site only);

"Minidoka County - adult psyllids (some positive for liberibacter);

"Bonneville County - adult psyllids (awaiting results from liberibacter test);

"Gooding County - adult psyllids (awaiting results from liberibacter test).

"Other counties where scouting is occurring but no psyllids have been found: Madison, Bingham (2 sites) and Canyon (4 sites)

"Samples submitted by crop consultants or growers:

Elmore County - adult psyllids (some positive for liberibacter);

"Canyon County - adult psyllids (some positive for liberibacter);

"Minidoka County - adult psyllids (positive for liberibacter).

"No colonization of psyllids has been detected in scouted fields; i.e., we have yet to find any nymphs in fields. All psyllids have been adults trapped on yellow sticky cards, with the exception of 2 sites in Twin Falls County that were collected with a vacuum sampler. First detection of liberibacter-infected potato psyllids was June 19 in Twin Falls County. Plants and tubers with zebra chip symptoms (confirmed by molecular tests) were first detected July 17 in Twin Falls County. Additional samples have been submitted since that date and are awaiting confirmation.

"We encourage everyone to increase scouting efforts. Ensure adequate insecticide treatment of the perimeter of fields, which may be missed by aerial application; psyllids are known to colonize fields first along the perimeter. Both potato psyllids and liberibacter are known to not be favored by very hot weather, but the role that weather has played in our findings to date or in disease epidemiology in general remains unclear.

"Refer to the sites below for guidance on scouting and IPM programs for potato psyllids.

"To view the full alert, and to download any attached files, please go to
www.pnwpestalert.net."

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