alfalfa pests
Dr. Clint Shock, Superintendent at the OSU Malheur County Experiment Station is reporting that lots of aphids, weevils, and lygus are being found in alfalfa hay fields near Nyssa and Vale. Oregon.
sugarbeet root maggot
The following information was provided by Dr. Erik J. Wenninger, Entomology and Extension Specialist with the University of Idaho at the Kimberly Research & Extension Center.
The degree day calculator (hosted by the Integrated Plant Protection Center at Oregon State University) for the sugar beet root maggot fly shows that—depending on your location in the Magic Valley—we have accumulated more than 360 degree days since March 1, 2012. Peak flight of root maggot flies should occur after 360 accumulated degree days when the maximum high temperature exceeds 80 degrees F. In the Mini-Cassia area, this usually occurs around the 2nd of June, but with warmer weather this year, peak flight in Rupert was predicted to have occurred on May 14.
Monitoring flies adjacent to your sugar beet fields using orange sticky stake traps will provide even more useful information regarding the local population densities of flies. The Amalgamated Sugar Company monitors flies with sticky stake traps throughout the Mini-Cassia area and posts the counts on their website: http://www.srcoop.com/ The economic threshold for application of granular insecticides against root maggots is an accumulative total of 40-50 sugar beet root maggot flies per sticky stake trap (the threshold varies depending on your contract price per ton). In the Mini-Cassia area, which historically has had high root maggot pressure, growers should consider an insecticide application 10 days before exceeding threshold captures on sticky stakes. Otherwise, insecticide applications should be made within 10 days before or after reaching the threshold (the closer to the threshold date, the better). Activation of granular insecticides should be accomplished by irrigation as soon after application as possible. See University of Idaho publication CIS 999, IPM Guide to Sugar Beet Root Maggot: http://www.uiweb.uidaho.edu/sugarbeet/insc/sbmaggot.htm
You can monitor degree day accumulation for sugarbeet root maggots as follows:
1) Log onto: http://uspest.org/cgi-bin/ddmodel.pl?spp=srm
2) Select “Sugarbeet Root Maggot Bechinski et al. 1990” degree day model from the “Select degree day model….” drop down box at the top of the form
3) In the “Select location” box, select a location in the drop down box best describing your location (e.g. “RUPERT id agmet” in the “Washington, Idaho” box if you want information for a field near Rupert). Make sure to select “None” at the top of the lists in the other two location boxes.
4) Leave the “Or upload your own…” box blank
5) In the “Forecast:” area, enter your zip code or your city, state in the “NWS zipcode/city, state” box, or the location nearest your field from the “or weather.com site” drop down box to the right). This selection forecasts 7 days forward based on the local weather forecast (beyond 7 days the forecast is based on the historical average). The predicted date of peak fly flight will vary depending on the forecast location selected, so pick the one closest to your location. Select “none” to have the forecast based only on the historical average.
6) Select the location nearest your field in the “Select historical average forecast location” area. Your selection here should match, as close as possible, your selection in the “Select location” area above: there may not be an exact match. As above, select “none” in the other two boxes.
7) Make sure the “Table” and “graph” boxes are checked (and the “precipitation” if you want rainfall information) and click the “Calc” button. A table with the current degree day accumulations matching your selection should appear. There should also be a graph near the bottom showing the current year accumulation compared to the historical average for your selections.
onion thrips
Dr. Mike Thornton from the UI Parma station is reporting that they are starting to find a few onion thrips in their plants samples. While we have not yet reached the action threshold of 1 thrips per plant, the warm weather forecast for the next week means that insect populations may build very rapidly. He advises that growers begin scouting for thrips in the next few days to help in scheduling the first insecticide application.
Idaho
REMINDER
Idaho zebra chip (ZC) and potato psyllid workshops scheduled for this week.
To help industry prepare for psyllid monitoring and scouting, several training sessions have been scheduled. The workshops will have an open format, and we ask people to come any time that fits their schedule during each session. This will allow more personal attention and access to specimens and samples as people come and go. Dates, times, and locations for these sessions are:
May 15, 9:30 – noon, Parma Research and Extension Center, 29603 U of I Lane, Parma
May 16, 9:30 – noon, Miller Research LLC, 426 East 200 North, Rupert
May 17, 9:30 – noon, Idaho Falls R & E Center, 1776 Science Center Dr.
Colorado Potato Beetle
The following information was provided by Dr. Mike Thornton, Potato Specialist at the UI Parma R and E Center.
“The mild winter means that plenty of volunteer plants are starting to emerge in fields that were in potatoes last year. These volunteers can allow many potato disease and insect problems to get started before moving into nearby commercial fields. Specifically, I have seen a few adult Colorado potato beetles (CPB) feeding on emerged volunteers. These adults don’t usually cause a lot of damage, but will be laying eggs very soon. The first generation of CPB that hatches from these eggs can be very damaging in fields that have not been treated with a systemic insecticide at planting, and these fields should be scouted after emergence.”
lygus bug
The following information was provided by Dr. Jim Barbour, IPM Specialist at the UI Parma R and E Center.
The Lygus degree day calculator hosted by Integrated Plant Protection Center at Oregon State University and the IPM Centers - PNW Coalition (http://pnwpest.org/cgi-bin/ddmodel.pl?spp=lyg) shows that, depending on your location in the Treasure Valley, we have accumulated about 230 days since January 1, 2012. Peak emergence of lygus bug 1st and 2nd instar nymphs should occur right around 272 accumulated degree days: this varies year-to-year, but usually occurs around mid-May, and is the time to begin monitoring for lygus bugs in alfalfa seed fields. In the Treasure Valley that is predicted to occur between May 10 and May 14, depending on your location.
You can monitor degree day accumulation using the link provided above and:
1) Select “ lygus bug [alfalfa seed]Ben Simko 2000” degree day model from the “Select degree day model….” drop down box at the top of the form: the lower and upper temperature threshold boxes (52 and 130 degrees F) and the start and end date boxes (Jan 1 and Aug 31) should automatically fill.
2) In the “Select location” box, select a location in the drop down box best describing your location (e.g. “parma id agrimet” in the “Washington, Idaho” box if you want information for a field near Parma). Make sure “None” is selected in the boxes for the other two locations.
3) Leave the “Or upload your own…” box blank
4) In the “Forecast:” area, enter the zip code or your city and state in the “NWS zip code/city, state” box, or the location nearest your field from the “or weather.com site” drop down box to the right). This selection forecasts 7 days forward based on the local weather forecast (beyond 7 days the forecast is based on the historical average). The predicted date of peak 1st and 2nd instar will vary depending on the forecast location selected, so pick the one closest to your location. Select “none” to have the forecast based only on the historical average.
5) Select the location nearest your field in the “Select historical average forecast location” area. Your selection here should match, as close as possible, your selection in the “Select location” area above: there may not be an exact match. As above, select “none” in the other two boxes.
6) Make sure the “Table” and “Graph” boxes are checked (and the “Include precipitation…” if you want rainfall information) and click the “Calc” button. A table with the current degree day accumulations matching your selection should appear. There should also be a graph near the bottom showing the current year accumulation compared to the historical average for your selections.
