2013 Potato Insect Pest Survey for the Columbia Basin of Washington
Aphids, Leafhoppers, Tuberworm, and Psyllids
The insect pest survey provides the potato industry with current information about the size and location of important insect pest populations in the Columbia Basin.
INSECT MONITORING REPORTS
Report for May 17, 2013
BLH populations are building up in some parts of the Columbia Basin. Yellow sticky traps near Mattawa had the highest counts this week, ranging from 47 to 261 BLH per trap, and averaging 137. This is a lot more than we found last season! Traps on the Royal Slope also had high BLH counts, ranging from 1 to 77 BLH per trap, and averaging 24.
Beet leafhoppers are important pests because they transmit BLTVA, a phytoplasma that causes purple top disease in potatoes. In the Columbia Basin, the first spring generation of BLH usually migrates towards potato fields in late May and early June, with a peak flight in late June. Yellow sticky traps placed near potato fields are one way to monitor BLH. Information about setting up traps and identifying BLH can be found in the article, “Beet Leafhopper Monitoring with Yellow Sticky Cards”. Treatment thresholds based on BLH numbers on traps have not been established, but we know that the risk of infection increases as BLH populations become large. If the numbers on traps build up to 40 or more BLH per week, then it is probably time to be concerned. A typical weekly catch during peak BLH activity is 100. Eliminating weed hosts (wild mustards, Russian thistle, kochia) in areas surrounding potato fields is an important cultural management approach for BLH. Potato growers may also select cultivars that are less susceptible to purple top (Ranger, Umatilla, and Norkotah are considered highly susceptible; Russet Burbank is susceptible; and Alturas and Shepody are moderately susceptible). A number of insecticides are labeled for use on potatoes to control leafhoppers. Systemic at-planting insecticides, especially those with longer residual activity applied at the maximum allowed rate, have been shown to provide some early season control of BLH. Results may vary depending on the product used, application rate, soil and environmental conditions, and insect pressure. Foliar insecticides may also be used to control BLH. These are usually applied in May, June, and sometimes July. Insecticides with long residual activity (10-14 days) are preferred. If you apply a non-systemic insecticide, it may be necessary to shorten the application interval during periods of rapid plant growth to ensure adequate plant coverage. Remember to always read and follow instructions on the pesticide label. For more information about managing BLH, visit IPM Guidelines for Insects and Mites in ID, OR, and WA Potatoes and the PNW Insect Management Handbook.
Monitoring updates about potato psyllids will be coming soon. Last season, we first detected potato psyllids in Columbia Basin potato fields on June 11th. There will be two Psyllid/Zebra Chip/Insect Workshops in Washington soon: June 3, 2:30-5 pm in Eltopia at Ag Development Group Research Farm, 2621 Ringold Rd.; and on June 4, 10:00-12:30 pm in Moses Lake at the WA Potato Commission office, 108 S Interlake Rd.
Potato psyllids are important pests mostly because they can transmit a bacterium (Candidatus Liberibacter solanacearum) to potatoes that causes zebra chip disease (ZC). This disease reduces both yield and tuber quality and has lead to serious economic losses in some regions. ZC was first detected in potato fields in the Columbia Basin in 2011, and occurred again in 2012. Yellow sticky cards are recommended for detecting psyllid migration into an area. The cards should be placed inside the field, near the field edge, and just above the canopy level. It is best to have five or more yellow sticky cards around the field. Another method for sampling adult psyllids is to use an inverted leaf blower with a mesh net secured to the end of the cylinder (see photo on the sidebar). This method is better for detecting low population densities than the sticky cards. Operate the machine (in vacuum mode) above the potato plants for at least 5 minutes, 5-10 feet from the edge of the field, and then carefully remove the net from the end of the cylinder. It helps to transfer the insects from the net to a plastic bag that you can seal, and then look for the tiny winged adults. If you place the bag in the freezer for a while, you can slow the buzzing insects down which will make it easier to scan the bag. Other life stages of the psyllid may be found by collecting several leaves (mid-plant) from the outer rows of the field, and then scanning the underside (with a hand-lens) for the tiny nymphs and eggs. It is also recommended to scout for psyllids in cull piles and volunteer potatoes. For more information about psyllids, including insect identification, monitoring, and control recommendations, read Biology and Management of Potato Psyllid in Pacific Northwest Potatoes and Potato Psyllid Vector of Zebra Chip Disease in the Pacific Northwest.
We will begin monitoring aphids soon.
Aphids are important pests because they transmit several important potato viruses, especially potato leafroll virus (PLRV) and potato virus Y (PVY). Green peach aphids are the most important vector of PLRV, which has caused substantial yield and tuber quality losses in the Columbia Basin. PLRV causes net necrosis in some cultivars, an unacceptable tuber defect in processing potatoes. PVY can also result in significant yield losses, and some strains cause tuber defects. Potato growers should monitor fields for aphids at least once a week, because early recognition and control of aphids is the best tactic in limiting spread of potato viruses. Current recommendations are to treat long-season storage potatoes as soon as wingless aphids are detected. Low tolerances have been established because even a low incidence of seed borne PVY and PLRV can spread rapidly if aphids go unchecked.
Moths were found at one location this week. One trap near the WA/OR border had 11 PTW moths. This location is one that often attracts PTW.
Potato tuberworm (PTW) was first recognized as an important pest of potatoes in the southern Columbia Basin in 2003. PTW larvae feed on tubers causing damage that renders them unmarketable. Potato growers with fields south of Connell, WA are recommended to pay close attention to regional trapping data, and should deploy pheromone traps. Infestations of PTW are highly localized, and it is risky to conclude too much from traps that may be several miles away. Information about setting up traps and identifying PTW moths can be found in the article, “Tuberworm Monitoring with Pheromone Traps”. Trap counts from mid-season to harvest are particularly important to watch. Pre-harvest control measures may be warranted in fields where PTW moths in pheromone traps are found to be increasing every week, especially in August-October.
Pest Data Mapping
Click on the map to view insect population data (http://www.nwpotatoresearch.com/IPM-Home.cfm).
- 2012 IPM Guidelines for Insects and Mites in ID, OR, and WA Potatoes
Authored by PNW entomologists, this report is a set of recommendations as to how to best manage potato insect pests.
- PNW Insect Management Handbook
This handbook is a tool for making decisions regarding the management of important insect pests in the PNW. For information about potato pests, select the Chapter: Irish Potatoes.
- Northwest Potato Research: Integrated Pest Management
Find information about insect pests, insect-transmitted diseases, and beneficial insects. View regional pest data mapping from this website.
- Beet Leafhopper Monitoring with Yellow Sticky Cards
This article explains how to deploy yellow sticky card traps for monitoring beet leafhoppers. It also provides information about correctly identifying beet leafhoppers, as there are many look-alike leafhoppers in the Columbia Basin.
- Biology and Management of Potato Psyllid in Pacific Northwest Potatoes
This article by A. Schreiber, A. Jensen, and S. Rondon includes information about zebra chip disease, explains how to identify potato psyllids, and provides options for controlling psyllids.
- Biology and Management of the Potato Tuberworm in the PNW
This PNW Extension publication is an excellent resource for potato tuberworm information.
- Potato Psyllid Vector of Zebra Chip Disease in the PNW
This OSU Extension publication provides extensive information about the biology, ecology and management of potato psyllid in the PNW.
- Recognizing Potato Psyllid Adults
- Tuberworm Monitoring with Pheromone Traps
This article explains how to set up traps for monitoring tuberworm moths, and how to identify them correctly.
- University of California IPM Pest Management Guidelines – Potatoes
- Northwest Potato Research - WA, OR, ID Potato Commissions
- 2012 Potato Insect Pest Survey Results
Detailed weekly reports from the 2012 growing season, and the 2012 Annual Report.
- 2011 Potato Insect Pest Survey Results
Detailed weekly reports from the 2011 growing season, and the 2011 Annual Report.
- 2010 Potato Insect Pest Survey Results
Detailed weekly reports from the 2010 growing season, and the 2010 Annual Report.
- 2009 Potato Insect Pest Survey Results
Detailed weekly reports from the 2009 growing season, and the 2009 Annual Report.
This project is sponsored by the Washington State Potato Commission.
Pest alerts via email!
Subscribe to receive weekly pest alerts via e-mail by sending an e-mail to Carrie Wohleb (email@example.com).
The Washington State Potato Commission is offering free supplies to Washington growers for trapping leafhoppers and tuberworm moths. To receive supplies for trapping these insects, simply call the commission office (509) 765-8845 or send an e-mail to firstname.lastname@example.org
|Potato tuberworm moth|
|Green peach aphid|
|Psyllid sampling with a leaf blower/vacuum|
For more information about the potato insect pest survey contact: