WSU Extension

Hortsense

Potato
 
Disease
Bacterial soft rot and blackleg 
Late blight 
Potato leafroll mosaic (Leafroll) 
Powdery scab 
Rhizoctonia canker (Black scurf) 
Scab (Common) 
Verticillium wilt (Potato early dying) 
Insect
Colorado potato beetle 
Potato flea beetles 
Slugs 
Wireworms 



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Caption: Colorado potato beetle adult
Photo by: Clemson University
  
Potato : Colorado potato beetle
(revision date: 5/15/2015)


Biology
The adult Colorado potato beetle is a broad (1/4" wide), yellow-and-black striped beetle up to about 3/8" in length. The adults overwinter in the soil, emerging in the spring. They lay clusters of yellow eggs on the underside of the leaves of host plants. The humpbacked larvae are reddish-orange and have two rows of black spots along each side. Both larvae and adults chew holes in leaves and leaf margins. They may cause serious defoliation of potatoes. Other plants which may be attacked include pepper, tomato, petunia, and other potato relatives including weeds such as nightshade and groundcherry. They occur only east of the Cascades.
Management Options

Non-Chemical Management
  • Eliminate weeds in and around the garden, especially nightshade and related species.
  • Hand-pick and kill adults and larvae.
  • Crop rotation to non-host plants may be useful if host species are not planted nearby.
Select non-chemical management options as your first choice!

Chemical Management

Apply according to label instructions when potato beetle is first seen. Direct treatment especially where stems of potato vines enter soil. Several applications may be needed. Beneficial nematodes can be ordered through certain nurseries. They can be applied to control the larval stage if soil temperatures are warmer than 52 degrees F. Nematodes should not be applied in direct sunlight and the soil should be saturated with water prior to application.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Azamax Botanical Insecticide, Miticide, & Nematicide [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 71908-1-81268
  • Bonide Captain Jack's Deadbug Brew R-T-U [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 4-472
  • Bug Buster-O [Organic]
    Active ingredient: pyrethrins  |  EPA reg no: 1021-1771-54705
  • Bull's-Eye Bioinsecticide
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-56872
  • ferti-lome Borer, Bagworm, Tent Caterpillar & Leafminer Spray
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-7401
  • Monterey Garden Insect Spray [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-54705
  • Naturalis L
    Active ingredient: Beauveria bassiana  |  EPA reg no: 53871-9
  • NIMBIOSYS Neem Oil [Organic]
    Active ingredient: neem oil, cold pressed  |  EPA reg no: 84181-2
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • This list may not include all products registered for this use.
Images

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Caption: Colorado potato beetle adult
Photo by: Clemson University
Caption: Colorado potato beetle adult
Photo by: Unknown
Caption: Colorado potato beetle larva
Photo by: Unknown