Insect Thresholds of Potatoes

Pest		Threshold	Reference
	Colorado potato beetle	Depends on crop value and control costs; ranges from 2-10 plants with larval colonies per 100 feet of row	UI EXT 757 (1995)
	flea beetles	50 shotholes per leaflet	Potato Health Management (1993)
	green peach aphid      southwestern Idaho        central and eastern Idaho	40 or more per 50 leaves during each of two consecutive weeks before 1 August 10 or more per 50 leaves during each of two consecutive weeks before 1 August	UI CIS 399 (1977)
	loopers      early season      late season	4 larvae per foot of row 8 larvae per foot of row	UW CES
	variegated cutworm      early season      late season	4 larvae per foot of row 8 larvae per foot of row	UW CES
	wireworms	1/2 - 2 larvae per bait station	UI EXT 760 (1994)

Thresholds are not available for these pests:   cutworms/armyworms, -army cutworm, -black cutworm, redbacked cutworm, -spotted cutworm, -variegated cutworm, -western yellowstriped armyworm; blister beetles; garden symphylan; leafhoppers; leather jacket (crane fly); lygus bugs; potato aphid; seedcorn maggot; thrips; two-spotted spider mite; white grubs.

References:  UI CIS 399 The green peach aphid, UI EXT 757 Integrated pest management guide to Colorado potato beetle; UI EXT 760 Integrated pest management guide to wireworms in potatoes; Vegetable Crop Scouting Manual, University of Wisconsin, Cooperative Extension Service (no date), R.C. Rowe, editor.  1993. Potato Health Management. APS Press (ISBN 0-89054-144-2).

Revised: August 12, 2008

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