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WSU Potato Alerts

Friday Apr 07, 2023

The WSU Potato Alerts e-newsletter covers topics important to potato production in the irrigated Columbia Basin. The alerts are issued weekly during the potato growing season, with additional issues sent on special occasions. If you want to subscribe to our alerts, click HERE and select Potato Pest Alert. A summary of each issue (since Aug. 2021) is shown below (click on the issue date to see the full report).

July 5, 2024 WSU POTATO ALERT - 9th potato alert for the 2024 growing season.

 

 

June 28, 2024 WSU POTATO ALERT - 8th potato alert for the 2024 growing season.

Beet leafhopper numbers are up again this week. This issue also includes updates on lygus bugs, Colorado potato beetles, and aphids.  

 

June 21, 2024 WSU POTATO ALERT - 7th potato alert for the 2024 growing season. 

Beet leafhopper numbers may have reached their first peak. However, the average trap count is moderately high and there are some "hot spots" with very high numbers. It's been a relatively slow week for the insect monitoring network. One of the most prevalent insects in our samples was the big-eyed bug, a beneficial predator.

Photo by Ronald Smith, Auburn University, Bugwood.org.

 

June 14, 2024 WSU POTATO ALERT - 6th potato alert for the 2024 growing season.

Beet leafhopper counts are high and the risk for BLH-transmitted diseases is higher. Pathogen prevalence maps showing weekly test results for virus (BCTV) and phytoplasmas carried by BLH can be found on the Potato DAS. This issue includes updates on other insects including lygus bugs, potato psyllids, and Colorado potato beetles. There is also information about root knot nematode DDs.

 

June 12, 2024 SPECIAL ISSUE OF WSU VEGETABLE ALERTS - beet leafhoppers

This special issue is a guide for monitoring and managing beet leafhoppers in the Columbia Basin.  The BLH is a serious menace to several crops in the Columbia Basin because it transmits pathogens, including the BLTVA phytoplasma that causes purple top in potato and carrot, beet curly top virus (BCTV) that causes curly top in many plants, and Spiroplasma citri that affects carrot.

 

June 7, 2024 WSU POTATO ALERT - 5th potato alert for the 2024 growing season. 

When scouting potato fields, don't overlook the beneficial predatory insects and arachnids that feed on pest insects. This issue features a beneficial predator identification quiz. There are also updates about beet leafhoppers, late blight, root knot nematodes, and more.

 

May 31, 2024 WSU POTATO ALERT - 4th potato alert for the 2024 growing season.

Save the date for two field days in June. There will be a yellow nutsedge field day on June 13th, and the WSU Potato Field Day on June 27. This week's issue includes updates on beet leafhopper and Colorado potato beetle. There is also a warning about late blight in row-closed potato crops.

 

May 24, 2024 WSU POTATO ALERT - 3rd potato alert for the 2024 growing season.

There was a decline in beet leafhopper counts this week, but we expect their numbers to resurge as the temperatures increase. Sign up for text/email alerts for Colorado potato beetles; they can be a helpful aid for scouting and timing insecticide applications. The Potato Virus Initiative team recently published an informative newsletter about their SCRI-funded project; a link is provided in this issue of WSU Potato Alerts. This issue also includes information about nematodes and a late blight update.   

 

May 17, 2024 WSU POTATO ALERT - 2nd potato alert for the 2024 growing season.

We saw a significant rise in beet leafhopper counts this week. The current numbers are alarming to see for this time of year. Outbreaks of BLH-transmitted diseases tend to be more severe when the first generation of BLH peak in May, rather than in June.

 

May 10, 2024 SPECIAL ISSUE OF WSU POTATO ALERTS - Colorado potato beetle

Get ready to outsmart those pesky Colorado potato beetles. This special issue of WSU Potato Alerts is a comprehensive guide to managing one of the most notorious potato pests.

 

May 10, 2024 WSU POTATO ALERT - 1st potato alert for the 2024 growing season.

It's time to embark on our annual quest for insect pests in potato fields across the Columbia Basin of Washington. This issue includes current information about beet leafhopper and Colorado potato beetle. If you have a Potato DAS account, you can sign up for text/email alerts to notify you when CPB life stages will reach important management thresholds.

 

September 15, 2023 WSU POTATO ALERT - 21st potato alert for the 2023 growing season.

A final update on late season pests, potato psyllid and potato tuberworm.

 

September 8, 2023 WSU POTATO ALERT - 20th potato alert for the 2023 growing season

This issue includes updates on potato psyllid and tuberworm.

 

September 1, 2023 WSU POTATO ALERT - 19th potato alert for the 2023 growing season

Potatoes are easily bruised during harvest and storage loading operations. This issue includes a review of the two most common types of bruising, and some tips to minimze bruise. There are also updates on potato psyllids and potato tuberworm.

 

August 25, 2023 WSU POTATO ALERT - 18th potato alert for the 2023 growing season.

Symptoms of zebra chip disease (spread by potato psyllids) can go unnoticed, and by the time you find it, it may be too late to prevent significant damage. That's why risk-averse growers use a "no gaps" insecticide program to control this pest. This alert includes updates on potato psyllids, potato tuberworm, late blight, and bacterial soft rot.

 

August 18, 2023 WSU POTATO ALERT - 17th potato alert for the 2023 growing season.

Bacterial soft rot is one of several potato tuber diseases associated with high soil temperatures and excessive soil moisture. Be careful not to overwater the crop. Potato psyllid numbers have increased, but are low compared to many previous years for this time of the season. This report also includes updates on potato tuberworm, aphids, and beet leafhoppers.

 

August 11, 2023 WSU POTATO ALERT - 16th potato alert for the 2023 growing season.

Last week's weather was conducive for late blight, but no disease has been reported so far this season. Keep an eye out for symptoms of late blight. This report also includes updates on potato psyllids, tuberworm, aphids, and beet leafhoppers.

 

August 11, 2023 SPECIAL ISSUE OF WSU POTATO ALERTS - potato pink eye

This special issue of WSU Potato Alerts features information about potato pink eye, an important physiological disorder that is associated with excessive soil moisture combined with high soil temperatures.

Early symptoms of potato pink eye (photo by the Maine Potato Board).

 

August 4, 2023 WSU POTATO ALERT - 15th potato alert for the 2023 growing season.

Spider mites are showing up in some potato fields now. Learn more about scouting for spider mites and managing them. This alert also includes updates on several insect pests, a review of June & July air temperatures, and a late blight update. 

 

July 28, 2023 WSU POTATO ALERT - 14th potato alert for the 2023 growing season.

Potato fields across the region are showing mild to severe symptoms from lygus bug feeding on plants. Some images are included to review possible symptoms and highlight some cultivar differences. Late blight has not been reported this season, but the probabilities that it will occur are higher now compared to last month. Don't mistake early tipburn symptoms for late blight. 

Early symptoms of tipburn, before it dries and becomes brittle.

 

July 21, 2023 WSU POTATO ALERT - 13th potato alert for the 2023 growing season.

We found aphids in 100% of the fields we monitored this week. The numbers were quite low in June, but have been increasing mid-season. Did you know that large aphid outbreaks in June were a common occurrence in the Columbia Basin before the 2010s? But that is no longer the case, probably due to the increased use of systemic neonicotinoid insecticides at-planting or at-hilling since the phase out of Monitor (methamidophos) and Temik (aldicarb) in potatoes that started in 2009 and 2010 respectively. 

 

July 14, 2023 WSU POTATO ALERT - 12th potato alert for the 2023 growing season.

Late blight has not been reported in the Columbia Basin, but recent stormy weather with cooler nights may have created favorable conditions for an outbreak. Lygus bug and aphid numbers are increasing. This issue introduces our new spray selection tool in the Potato DAS

 

July 7, 2023 WSU POTATO ALERT - 11th potato alert for the 2023 growing season.

Lygus bug and aphid numbers are increasing, beet leafhopper numbers continue to be at peak numbers, and second generation Colorado potato beetle larvae are emerging. But potato tuberworm numbers have been low this season. 

The CPB larvae on the left are newly emerged and are more likely to be controlled with an insecticide. Photos by Andy Jensen, NW Potato Research Consortium (left) and Carrie Wohleb, WSU (right).

 

June 30, 2023 WSU POTATO ALERT - 10th potato alert for the 2023 growing season.

The temperartures this June have been very good for growing potatoes. This alert includes an update on growing degree days and temperatures so far this season. Other news... the second generation of Colorado potato beetles have emerged, lygus bug and beet leafhopper numbers are high, and psyllid numbers are low.

Continuous air temperatures (recorded hourly) for E. Moses Lake in 2021, 2022, and 2023. 

 

June 23, 2023 WSU POTATO ALERT - 9th potato alert for the 2023 growing season.

This week's alert has a couple of quizzes where you can test your ability to identify potato psyllids, and beneficial insects. 

 

June 16, 2023 WSU POTATO ALERT - 8th potato alert for the 2023 growing season.

Potato psyllids are beginning to migrate to potato fields from overwintering sites. It's time to keep an eye out for this pest and consider management options that target adults psyllids as they enter the field. This alert includes guidance for monitoring potato psyllids and managing them with insecticides. There are also updates on lygus bugs and beet leafhoppers.

Andy Jensen, NW Potato Research Consortium, produced this guide "Psyllid Monitoring with Yellow Sticky Cards".

 

June 9, 2023 WSU POTATO ALERT - 7th potato alert for the 2023 growing season.

We are finding lygus bug nymphs in potato fields now, with the highest numbers in the Lower Columbia Basin. This issue describes different life stages of lygus bugs and the damage they can do to potatoes. There are also updates on beet leafhoppers and potato tuberworm. Keep an eye out for yellow nutsedge. And monitor for symptoms of late blight. 

Lygus bug nymphs; early instar (left) and late instar (right). Photos by Carrie Wohleb, WSU Extension.

 

June 2, 2023 WSU POTATO ALERT - 6th potato alert for the 2023 growing season.

This issue features information about nematodes, and includes scouting reports for beet leafhoppers and Colorado potato beetles. 

The pictures (above) show potatoes infested with Columbia root-knot nematodes (photos by Gerald Holmes, Cal Poly San Luis Obispo, Bugwood.org.

 

May 31, 2023 SPECIAL ISSUE OF WSU POTATO ALERTS - Colorado potato beetles (see May 10, 2024, for an updated version of this issue)

This special issue of WSU Potato Alerts features Colorado potato beetles (CPBs). It includes information about their life cycle, scouting tips, the importance of crop rotation and volunteer potatoes, CPB insecticides and insecticide resistance, and using the CPB phenology model the in Potato DAS.

 

May 26, 2023 WSU POTATO ALERT - 5th potato alert for the 2023 growing season. 

Beet leafhoppers (BLHs) are starting to migrate from overwintering weed hosts now. This alert features information about BLH and BLH-transmitted diseases, and introduces a new feature in Potato DAS, pathogen prevalence maps (see image below). 

 

May 19, 2023 WSU POTATO ALERT - 4th potato alert for the 2023 growing season.

This alert includes an update on beet leafhopper and Colorado potato beetles, and explains how pest contour maps (see image below) and phenology models on the Potato Decision Aid System can help growers make management decisions for these pests. 

 

May 12, 2023 WSU POTATO ALERT - 3rd potato alert for the 2023 growing season.

It's going to be hot next week, and growers with newly emerged or emerging potatoes may be at risk of "heat crinkle" and "candelabra". This issue also includes information about herbicide carryover in seed, a growing degree day update, and an introduction to the 2023 WSU Extension Potato Insect Pest Monitoring Network. 

The pictures show heat crinkle (left) and candelabra shoots (right). Photos from North Dakota State University (left), and C. Wohleb, WSU (right).

 

April 7, 2023 WSU POTATO ALERT - 2nd potato alert for the 2023 growing season.

This issue includes an outlook for potato psyllids in 2023 and accumulated growing degree days for potatoes so far.

Matrimony vine is a perennial relative of the potato, and an important overwintering host for potato psyllids in the Columbia Basin (photos by Carrie Wohleb, WSU).

 

March 22, 2023 WSU POTATO ALERT - 1st potato alert for the 2023 growing season.

Learn about the WA Commercial Potato Seed Lot Trial. This issue explains how to participate in the trial (if you are a commercial potato grower in WA) and describes a few of the seed-related problems the trial has helped to uncover over the years. Seed-borne potato issues, Potato Virus Y and herbicide carryover injury, are discussed in length.

Alturas cv. infected with PVY-O and PVY-NTN.
Alturas cv. infected with PVY-O and PVY-NTN. PVY-NTN can cause necrotic rings on the tuber surface. Photos by Carrie Wohleb, WSU (plants) and Bruce Watt, University of Maine (tuber). 

 

September 16th, 2022 WSU POTATO ALERT - 19th potato alert for the 2022 growing season.

This is the last weekly alert for the season. This issue includes a potato psyllid update and a comparison of this year's psyllid trapping program vs. other seasons.

 

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. 

Two spotted spider mite and eggs, and damage (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. 

Psyllid yellows. Photos by C. 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 ISSUE OF WSU POTATO ALERTS - 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).