Potato psyllids 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 led to serious economic losses. ZC was first detected in potatoes in the Columbia Basin in 2011. Potato psyllid feeding can also cause psyllid yellows, which can reduce yields and tuber quality. Potato psyllids usually start to move into potatoes in May or June. Yellow sticky cards can be used to detect psyllid migration into an area. The cards should be placed inside the field, very near the field edge, and right above the canopy. We recommend using the AlphaScents brand sticky cards, because they are stickier than most sticky cards and hold up under irrigation. It is best to have at least four yellow sticky cards around the field. For more information about trapping psyllids, read "Psyllid Monitoring with Yellow Sticky Cards". Other life stages of the psyllid can be found by collecting several leaves (mid-plant) from the outside rows of the field, and then scanning the underside (with a hand-lens) for the tiny nymphs and eggs.

Management recommendations. Management of psyllids relies on preventing populations from establishing in potato fields. One way to manage psyllids is to start with a systemic insecticide at planting or at layby, followed by foliar insecticide applications. The residual effect of at-planting neonicotinoids will depend on the time and rate of the application and the rate of plant growth. If only foliar insecticides are used, then it is recommended that applications begin upon first detection of potato psyllids in your area.

For more information about psyllids, including insect identification, monitoring, and control recommendations, read IPM Guidelines for Insects and Mites in ID, OR, and WA Potatoes.

Aphids can 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 can result in significant yield and tuber quality losses. 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 of the virus cause tuber defects. The tuber necrotic strains of PVY are becoming more prevalent in the PNW. In addition to spreading viruses, green peach aphids can cause significant feeding-damage that ends in the early senescence of plant foliage.

Management recommendations. The first step in preventing the spread of potato viruses by aphids is to plant certified seed potatoes. Early recognition and control of aphids is the next-best tactic in limiting spread of potato viruses, especially PLRV. Growers should monitor fields for aphids at least weekly to catch infestations early, as large infestations can be difficult to control even with multiple insecticide applications.

For more information about aphids, including insect identification, monitoring, and control recommendations, read IPM Guidelines for Insects and Mites in ID, OR, and WA Potatoes.

Potato tuberworm 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.

Management recommendations. It can be very important to manage PTW in the weeks leading up to harvest. Most of the feeding-injury to tubers occurs after vine kill or senescence when the larvae move from the foliage to the tubers. Damage to tubers increases the longer the potatoes stay in the field under dead vines. Insecticide treatments beginning 4-8 weeks before harvest have been shown to reduce damage. It is very important to consider the pre-harvest interval when selecting a product to apply. Cultural practices that reduce tuberworm damage can be effective and include: (1) eliminating cull piles and volunteers; (2) minimizing the time between vine kill or senescence and harvest or harvest under green vines; (3) maintaining soil moisture after vine kill to prevent soil cracking; and (4) maintaining more than 2-inches of soil over tubers.

For more information about PTW, including insect identification, monitoring, and control recommendations, read IPM Guidelines for Insects and Mites in ID, OR, and WA Potatoes.

INSECTICIDE USE & EFFICACY CONSIDERATIONS: Managing insect pests in Columbia Basin potatoes can be challenging because so many pests can overlap and insecticides vary in what they control. The table below is a quick reference to insecticides labeled for use on potatoes. It is not a complete list and is not meant as an endorsement of these products.

Trade Name1	Active Ingredient	IRAC Group3	Colorado Potato Beetle	Beet Leafhopper	Psyllid	Aphid	Looper Cutworm Armyworm	Mites	Potato Tuberworm	Thrips	Lygus
Lannate (SP, LV)	methomyl	1A	G*	P	G (A)*	G	G		G	G*	G*
Vydate C-LV	oxamyl	1A	G	G	S	G	G*	S		G*	G*
Dimethoate (and others)	dimethoate	1B			G (A)*	G
Imidan 70-W AG	phosmet	1B	G		G		G*		G
pyrethroids2	various	3	G	G	G (NA)		G		G
Scorpion 35SL, Venom	dinotefuran	4A	G	G	G (ENA)
Platinum	thiamethoxam	4A	G	G	G (ENA)	G
Cruiser 5FS	thiamethoxam	4A	G	G	G (ENA)	G
Belay	clothianidin	4A	G	G	G (ENA)*	G
Admire Pro	imidacloprid	4A	G	G	G (ENA)	G
Assail (30SG, 70WP)	acetamiprid	4A	G	G	G (A)*	G
Actara	thiamethoxam	4A	G	G		G
Transform WG	sulfoxaflor	4C		G	G (NA)	G					G*
Sivanto	flupyradifurone	4D	G	G	G (NA)	G					G*
Delegate WG	spinosad	5	G		G (N)*		G		G*	G	G*
Entrust	spinosad	5	G		G (N)*		G		G*	G	G*
Radiant SC	spinetoram	5	G		G (N)*		G		G	G	G*
Agri-Mek SC (and others)	abamectin	6	G		G (NA)			G	G	G*
Fulfill	pymetrozine	9B			G (NA)*	G
Onager Optek, Hexamit	hexythizox	10A			G (EN)*			G
Comite	propargite	12C						G
Rimon 0.83 EC	novaluron	15	G (L)		G (N)*		G (L)		G (L)	G*	G (N)*
Trigard	cyromazine	17	G (L)
Torac	tolfenpyrad	21A	G		G (NA)	G				G
Miteus	fenpyroximate	21A		G	G			G
Avaunt	indoxacarb	22					G		G
Movento	spirotetramat	23			G (EN)	G		S		G
Oberon (2SC, 4SC)	spiromesifen	23			G (EN)			G
Acramite 4SC	bifenazate	20						G
Coragen	chlorantraniliprole	28	G				G		G
Exirel, Verimark	cyantraniliprole	28	G		G (A)	G	G		G	G*
Beleaf 50 SG	flonicamid	29			G (NA)*	G				G*	G*

¹ This is not a complete list and other insecticides may be available in similar formulations with the same active ingredient. There may be some formulations of the active ingredient that are not registered for use on potatoes. This list does not include products that are package mixes with multiple active ingredients.

² Some commonly used pyrethroid products include: Asana XL (esfenvalerate), Brigade 2EC, Battallion 2EC, Capture LFR (bifenthrin), Baythroid XL (beta-cyfluthrin), Mustang (zeta-cypermethrin), Tombstone (cyfluthrin), and Warrior II (lambda-cyhalothrin). Do not use pyrethroid insecticides between June 15 and two weeks before harvest to preserve beneficial insects. Broad-spectrum insecticides like pyrethroids and organic pyrethrins are known to kill beneficial insects that help to keep pests like aphids, psyllids, and spider mites in check.
In the columns, “G” denotes good control of the pest and “S” denotes suppression. See the product label for specific information about control. In some columns, the letters in ( ) specify control of E=eggs, L=larvae, N=nymphs, and A=adults. In some columns * indicates that the insecticide is known to control the pest, but it is not listed on the product label.

³ IRAC = Insecticide Resistance Action Committee. The IRAC code denotes mode of action. Except for IRAC 4 groups, make no more than two consecutive applications of products with the same mode of action before rotating to a different mode of action. Do not apply a foliar IRAC group 4 product (neonicotinoid) if one was applied to the seed or soil earlier in the season. Many of the pests (aphids, psyllids, Colorado potato beetles) have developed resistance to neonicotinoid insecticides in other regions.

Additional Tips for Insecticide Application:
Read the product label. Pay particular attention to notes about usage, including timing, mixing, and application methods, because they can make big differences in efficacy. Use the right kind of surfactant for the product you are applying. Adjust the pH of the spray solution if the label recommends doing so. Make sure the products in your tank mix will be compatible before you mix them, and always use the recommended mixing order. Consult product representatives if you have questions. Maximum residue limits (MRLs) for some of the products listed above may not be established for all export countries.