2015 Potato psyllid monitoring program underway
The University of Idaho, in collaboration with Miller Research and several crop consultants across the state is continuing our monitoring program for potato psyllids, zebra chip, and liberibacter (Lso), the bacterium that causes zebra chip.
Monitoring on 17 of our “Light” sites began last week (all in the Treasure Valley) and 4 of our “Intense” sites (all in the Magic Valley) with the deployment of sticky cards. We found no potato psyllids on cards at any of these sites this week. Deployment of sticky cards began on many more sites this week as well. We expect to have a total of around 75 “Light” sites and 13 “Intense” sites across the state; this is similar to last year.
Online spreadsheets showing details of the psyllid captures in potato fields will go live next week.
We have been monitoring for psyllids within presumed overwintering habitat, including bittersweet nightshade and field bindweed sites, and we found 8 adult potato psyllids and many nymphs on bittersweet nightshade this week in Twin Falls County (no psyllids were found in Treasure Valley sites this week). These psyllids are now in transit to Moscow to be tested for Lso.
More information and resources on potato psyllids and zebra chip, including management and scouting recommendations, can be found at the link below.
Click on the link(s) below for more information about this pest:
Weed management in potatoes
I’ve had many calls about weed control in potatoes because of high rainfall amounts, excessive soil moisture this spring.
Please see the attached WORD document for my thoughts on what may happen - what are the possibilities for weed control in potatoes due to these conditions.
Western Cherry Fruit Fly Treatment Forecast
According to the degree-day model from the Online Phenology and Degree-Day Models published at the OSU Integrated Plant Protection Center Website the forecasted dates for beginning treatment against Western Cherry Fruit Fly are: Ontario (May 25), Caldwell (May 29), Boise and Parma (June 4), Nampa (June 5) and Emmett (June 9). These are based on recommended first treatment at 1060 degree-days per "Orchard Pest Management" as published by the "Good Fruit Grower", Yakima 1993.
The first Idaho Western Cherry Fruit Fly for 2015 was recently found in a trap in Homedale on May 19.
Iris yellow spot in volunteer onions
Several volunteer onions with Iris yellow spot virus (IYSV) have been found this week in Malheur County. Volunteer onions can serve as a source virus-infected thrips to move into this season's onion crop. Although the virus has not yet been found in this season's bulb fields, please continue to monitor fields carefully.
If you see potentially symptomatic plants that you would like tested for virus or have questions about thrips and the virus, please contact Stuart Reitz, Malheur County Extension, 541-881-1417.
Coddling Moth Timing
Wilbur Ellis Spray Scheduling for this week:
Fruitland/Payette May 24th 350 DD
Parma/ Roswell May 23rd 350 DD
SunnySlope May 23rd 350 DD
Magic Valley May 25 350 DD
Pocatello May 30 350 DD
Rexburg June15 350 DD
Onion Bulb Mites
Onion bulb mites have been found in several onion fields across the Treasure Valley. So far numbers appear to be low but they may be a contributing factor to stand losses.
Bulb mites can overwinter in the soil on decomposing vegetation or on volunteer onions in the field and in cull piles. Mild winter weather may have reduced their natural overwinter mortality.
Management relies on preventative measures, such as field sanitation and fumigation of fields with a history of problems.
If you have questions or concerns about onion bulb mites, please contact Stuart Reitz, Malheur County Extension, 541-881-1417, firstname.lastname@example.org.