How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PESTS

Flea beetles are minor pests of potatoes in California. The adults are small, 0.06 to 0.1 inch (1.5 to 2.5 mm) in length, metallic greenish brown to black in color, and tend to jump like fleas when disturbed. The larvae live in the soil, are slender, whitish, and about 0.25 inch (6 mm) long when mature.

Adult flea beetles overwinter in weeds or debris outside the field. In spring they feed on weeds until potato plants emerge, then fly into potato fields and feed on foliage.

DAMAGE

The beetles feed on leaves and stems resulting in many small holes in the leaves. This damage is seldom extensive enough to be of concern but may indicate future damage to the tubers. Watch for foliage damage when monitoring fields for this and other foliage-feeding pests, and keep records of your results (example form—108 KB, PDF). Most damage is caused by the larvae, which hatch from eggs scattered by adult females in the soil around potato plants. The larvae feed on roots, underground stems, and tubers. Larval feeding on tubers gives them a pimpled surface with small brown tunnels extending 0.06 to 0.25 inch (1.5 to 6 mm) into the tuber. When damage is extensive, the potatoes are unsuitable for processing.

MANAGEMENT

Systemic insecticides and foliar sprays applied for green peach aphid usually keep flea beetles below economically damaging levels. Even in areas where these treatments are not used, flea beetle infestations are sporadic and special controls are rarely necessary. Flea beetle damage often is not noticed until harvest, when it is too late for control measures.

• Summary of Important Links

Common name		Amount/Acre**	R.E.I.+	P.H.I.+
(trade name)			(hours)	(days)
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact Not all registered pesticides are listed. Always read label of product being used.
A.	DINOTEFURAN
	(Venom)	soil application: 6.5–7.5 oz	12	0
		foliar application: 1–1.5 oz	12	7
	MODE OF ACTION GROUP NUMBER1: 4A
	COMMENTS: Do not apply more than 0.754 lb/acre/season. If an application of imidacloprid (Admire Pro) was made at planting, choose another treatment material with a different mode of action Group number to help prevent the development of neonicotinoid resistance.
B.	IMIDACLOPRID
	(Admire Pro)	5.77–8.7 fl oz	12	0
	MODE OF ACTION GROUP NUMBER1: 4A
	COMMENTS: Apply to soil following label directions. Do not exceed 8.7 fl oz/acre/crop.
	. . . or . . .
	(Provado) 1.6F	3.8 fl oz	12	7
	MODE OF ACTION GROUP NUMBER1: 4A
	COMMENTS: Do not make applications at less than a 7-day interval, and do not apply more than 16 fl oz/acre/crop.
C.	ENDOSULFAN*
	(Endosulfan) 3EC	0.66–1.33 qt	48	1
	MODE OF ACTION GROUP NUMBER1: 2A
D.	METHAMIDOPHOS*
	(Monitor) 4	1.5–2.0 pt	72	14
	MODE OF ACTION GROUP NUMBER1: 1B
E.	CARBARYL*
	(Sevin) 80S	0.67–1.25 lb	12	7
	MODE OF ACTION GROUP NUMBER1: 1A
	COMMENTS: Not recommended in fields where potato psyllids are present because it promotes their population development.
**	See label for dilution rates.
+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
*	Permit required from county agricultural commissioner for purchase or use.
1	Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

IMPORTANT LINKS

• Surveying foliage pests form (108 KB, PDF)

PUBLICATION

UC IPM Pest Management Guidelines: Potato
UC ANR Publication 3463
Insects
L. D. Godfrey, Entomology, UC Davis
D. R. Haviland, UC Cooperative Extension, Kern Co.

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