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WSU Potato Alerts

Friday May 13, 2022

The WSU Potato Alerts e-newsletter is relevant to potato production in Washington's irrigated Columbia Basin. The alerts are issued weekly during the potato growing season. If you would like to subscribe to our alerts, click HERE and select Potato Pest Alert. A synopsis of the August 2021 through June 2022 issues are shown below (click on the issue date to see the full report).

 

September 9th 2022 WSU POTATO ALERT - 18th potato alert for the 2022 growing season. 

One potato psyllid tested positive for Lso last week. That is an infection rate of 0.1%, which has been the typical infection rate for psyllids collected using our trapping network in the Columbia Basin in Washington. This issue includes information about potato psyllid generations in the Columbia Basin, how they acquire and spread Lso, and some zebra chip management advice.

 

September 2nd 2022 WSU POTATO ALERT - 17th potato alert for the 2022 growing season.

This issue includes updates on potato psyllids, aphids, spider mites, and potato tuberworm. It also includes warnings about pink eye and tuber rots that can be more prevalent when late season temperatures are high and soil moisture levels are high.

Pink rot (left), Pythium leak (middle), and bacterial soft rot (right). Photos by Miller Research (top left, middle), G. Pelter, retired WSU (right), and B. Gunderson, WSU (bottom left).

 

August 26th 2022 WSU POTATO ALERT - 16th potato alert for the 2022 growing season.

Aphid numbers are increasing. It is important to keep an eye on aphid infestations because they can increase rapidly. Large populations can be difficult to control and may result in premature senescence. This is something to consider if you want to get several more weeks out of your crop.

Winged (left) and wingless (right) morphs of the green peach aphid (photos by Andy Jensen, NW Potato Research Consortium).

 

August 19th 2022 WSU POTATO ALERT - 15th potato alert for the 2022 growing season.

If your potato crop is still green and growing, then continue to monitor potato tuberworm, potato psyllid, and aphid numbers. These pests can cause problems late in the season. This issue of WSU Potato Alerts includes updates on those pests and a note about dodder, an interesting parasitic weed that we see occasionally in the Columbia Basin.

 

August 12th 2022 WSU POTATO ALERT - 14th potato alert for the 2022 growing season.

Yellow nutsedge is ranked among the worst weeds in the world. If you don't have a yellow nutsedge problem now, you should be vigilent to keep it that way. Learn how to identify it. This issue also includes updates on tuberworm, psyllids, spider mites, lygus bugs, beet leafhoppers, and aphids. 

Yellow nutsedge plants (photos by Carrie Wohleb, WSU).

 

August 5th 2022 WSU POTATO ALERT - 13th potato alert for the 2022 growing season.

Spider mites are being found in some potato fields in the Columbia Basin. This issue includes some tips on scouting for spider mites and management with miticide products. This issue also includes updates on potato psyllids, lygus bugs, tuberworm, beet leafhoppers, and aphids. 

A two-spotted spider mite and eggs, and potato leaves with webbing and spider mite feeding injury (photos by Andy Jensen, NW Potato Research Consortium and Carrie Wohleb, WSU).

 

July 29th 2022 WSU POTATO ALERT - 12th potato alert for the 2022 growing season.

This issue includes information about the pest contour maps (how they are made, how to interpret results) that are presented in most alerts and on the Potato DAS.  There are also updates about current pest numbers and images of some of the problems they can cause.  

 

July 22nd 2022 WSU POTATO ALERT - 11th potato alert for the 2022 growing season.

This issue includes updates about potato psyllids, lygus bugs, potato tuberworm, and aphids. Learn more about psyllid yellows disorder and about managing potato tuberworm. We have not seen spider mites yet, but expect to find them soon with the temperatures ramping up. 

Early Psyllid Yellows symptoms.jpg
Potato plants showing symptoms of psyllid yellows (photo by Carrie Wohleb, WSU).

 

July 15th 2022 WSU POTATO ALERT - 10th potato alert for the 2022 growing season.

It's time to monitor leaves for potato psyllid nymphs and eggs. Growers with potatoes south of Mattawa or Connell should also consider deploying pheromone traps to monitor potato tuberworm. This issue also includes updates about lygus bugs, beet leafhoppers, and aphids. And there is information about blackleg and toxic seed piece syndrome, two seed-borne issues that are being seen now in several potato crops in the Columbia Basin. 

A potato tuberworm pheromone trap and a potato tuberworm moth on a trap (photos by Andy Jensen, NW Potato Research Consortium).

 

July 8th 2022 WSU POTATO ALERT - 9th potato alert for the 2022 growing season.

Lygus bug numbers are increasing and we are starting to see symptoms of early feeding injury on potato plants. In the warmest parts of the Columbia Basin, potato growers may be seeing all Colorado potato beetle (CPB) life stages (late larvae, adults, eggs, and early larvae). This is the result of an overlap of the first and second CPB generations. In cooler areas, most of the CPB on potatoes are late instar larvae from the first generation. Volunteer potatoes can serve as an important refuge for CPB and a source of delayed infestations.

Colorado potato beetles on a volunteer potato plant in a sweet corn field (photo by Carrie Wohleb, WSU).

 

July 1st 2022 WSU POTATO ALERT - 8th potato alert for the 2022 growing season.

It's time to monitor potato psyllids and consider management options that target adult psyllids as they enter the field. This issue focuses on insect identification. There are quizes that help with potato psyllid, beet leafhopper, and beneficial insect identification. There is also a guide to sampling plants for aphids, lygus bugs, spider mites, and beneficial insects using a small bucket (our favorite method).

Can you identify the three potato psyllids? (photos by Andy Jensen, NW Potato Research Consortium)

 

June 24th 2022 WSU POTATO ALERT - 7th potato alert for the 2022 growing season.

Potato psyllids are starting to move into potato fields. This issue provides some guidance for monitoring and managing them. Beet leafhoppers have probably reached the spring generation peak. Aphids are starting to build up in some potato fields. This is also time to look for lygus bugs and keep Colorado potato beetles on the radar. Late blight has not been reported, despite conducive conditions for the disease.

Psyllid Monitoring Using Yellow Sticky Cards. A guide by Andy Jensen, NW Potato Research Consortium.

 

June 17th 2022 WSU POTATO ALERT - 6th potato alert for the 2022 growing season.

Beet leafhoppers (BLH) are probably nearing peak populations for the spring generation. We continue to be concerned that a large proportion of BLHs are carrying the beet curly top virus. Lygus bug nymphs are starting to appear in potato crops. This issue provides some nice pictures of lygus bug nymphs and adults of Lygus hesperus and Lygus lineolaris, the two species we often find in potatoes.

Lygus bug nymph and adult (photo by Whitney Cranshaw, Colorado State University, bugwood.org).

 

June 10th 2022 WSU POTATO ALERT - 5th potato alert for the 2022 growing season.

Beet leafhopper (BLH) counts are higher this week.  Most BLH are carrying the beet curly top virus; this is not a problem for potatoes, but may impact other crops that are more susceptible to curly top disease.  This issue also warns growers that it may be time to control Colorado potato beetles.

A beet leafhopper and coriander, bean, and carrot seed crops with BLH-transmitted diseases.
A beet leafhopper and coriander, bean, and carrot seed plants affected by BLH-transmitted diseases.

 

June 9th 2022 SPECIAL WSU POTATO ALERT - Late blight management tips.

Late blight has not been reported in the Columbia Basin this season, but the conditions have been favorable for the disease.  This special alert includes tips for managing late blight during the growing season.

Late blight lesions on a potato leaf (photo by Tim Waters, WSU)

 

June 3rd 2022 WSU POTATO ALERT - 4th potato alert of the 2022 growing season.

If you register for an account to use the Potato DAS, you will find a model for Colorado potato beetle development. It uses cumulative degree day information and weather forecasts to predict when overwintering adults will emerge, larvae will hatch, then pupate, and when the next generation of adults will emerge. This issue also includes a beet leafhopper update and a warning about late blight.

 

May 27th 2022 WSU POTATO ALERT - 3rd potato alert of the 2022 growing season.

Colorado potato beetle (CPB) adults are starting to emerge in the warmest parts of the Lower Columbia Basin. This issue includes recommendations for CPB management using insecticides. There is also information about beet leafhopper trapping results, a late blight forecast, and degree days for nematode development.

Colorado potato beetle life stages
Colorado potato beetle adult, eggs, and early instar larvae.

 

May 20th 2022 WSU POTATO ALERT - 2nd potato alert of the 2022 growing season.

Beet leafhoppers (BLH) were collected at 41% of the sites we monitored this week.  Most sites just had one or two per sticky card.  Exceptions were sites near George and Pasco with about 6 per card (still in the "low" range), and Mattawa with about 14 per card (inching up to "moderate").  This alert includes some important things to know about BLH, and reports about Colorado potato beetle and seed corn maggots.

BLH images
Beet leafhoppers (photos by Andy Jensen, NW Potato Consortium).

 

May 13th 2022 WSU POTATO ALERT - 1st potato alert of the 2022 growing season.

Washington just experienced its third coldest April since 1895, so it's no surprise that potato growing degree days are way behind normal.  This alert includes graphs of GDD accumulations for the 2022 potato crop in Pasco and Quincy and compares them to the past twelve years.  Also in the issue:  Setup of the 2022 WSU Extension Potato Insect Monitoring Network, early beet leafhopper and Colorado potato beetle reports, and predictions for potato psyllid numbers in 2022.

Methods used to monitor insects in and around potato fields.

 

September 17th 2021 WSU POTATO ALERT - 21st potato alert of the 2021 growing season, and will be the last regularly scheduled alert for the season.

Potato psyllids were found on sticky card traps in 73% of the fields monitored this week, and about 20% of those fields had counts in the very high range. Potato fields that are still green are likely to harbor psyllids that have been displaced from fields that have been harvested. But, this will only concern growers with potato fields that are about two or more weeks away from vine kill. The maps (below) show interpolated potato psyllid population densities across the Columbia Basin using our trapping network results. Go to Potato DAS and create a free account to scroll through the maps and view them in detail.

 

September 10th 2021 WSU POTATO ALERT - 20th potato alert of the 2021 growing season.

The 2021 growing season is quickly coming to a close, but there are a couple of pests to watch out for in the weeks leading up to harvest. Risk-averse growers are recommended to use a "no gaps" insecticide program to control psyllids from now until a week or two before vine kill. Most potato tubeworm feeding injury to tubers occurs after vine kill or senescence when the larvae move from the foliage to the tubers. 

Potato tubers showing tuberworm feeding damage (photos by Gary Pelter, retired WSU).

 

September 3rd 2021 WSU POTATO ALERT - 19th potato alert of the 2021 growing season.

A new space for the weekly resource you trust, Welcome to Potato Alerts with Potato DAS. Aphids are multiplying quickly in a lot of potato fields in the region. We found them in 86% of the fields we monitored this week. Additionally, the late blight forecast shows that late blight has not been reported in the Columbia Basin of Washington.

Wingless green peach aphids in the bottom of a plant-sampling bucket (photo by Carrie Wohleb, WSU).

 

August 27th 2021 WSU POTATO ALERT - 18th potato alert of the 2021 growing season.

This week, Potato psyllids were found on sticky card traps in 66% of the fields we monitored, Lygus bugs were found in 98% of the fields sampled, and it looks like significant Dodder issues this year.

 

August 20th 2021 WSU POTATO ALERT - 17th potato alert of the 2021 growing season.

Aphids were collected in most (92%) of the fields we monitored this week. Check fields at least weekly to monitor aphid populations. Lygus bugs got off to a slow start in the Columbia Basin this season, but this week we found them in 97% of the fields sampled.

Lygus bug adult (photo by Andy Jensen, NW Potato Consortium).

 

August 13th 2021 WSU POTATO ALERT - 16th potato alert of the 2021 growing season.

Aphid counts continue to climb. Aphids were collected in 100% of the fields we monitored this week. Have you seen Dodder? Dodder is a parasitic plant that can infest many different crops including potatoes, onions, carrots, asparagus, cucurbits, alfalfa, sugar beets and many weeds.

Dodder growing on potatoes (photos by Carrie Wohleb, WSU).