How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

The beet leafhopper is approximately 0.125 inches long, wedge shaped, and pale green to gray or brown in color. It may have dark markings on the upper surface of the body. It can be distinguished from Empoasca leafhoppers by its darker markings; Empoasca leafhoppers are a uniform green color. Beet leafhopper overwinters on rangeland weeds and migrates to sugarbeet and other crops in spring as its overwintering hosts die.

DAMAGE

Direct feeding by beet leafhopper causes relatively minor damage. Its pest status derives from its transmission of beet curly top virus. Beet curly top virus is an extremely destructive disease of sugarbeet as well as other crops (e.g., tomatoes). The leaves of plants infected with this virus are dwarfed, crinkled, and rolled upward and inward. Veins are roughened and often swollen. Roots become distorted, often with a proliferation of hair roots (not to be confused with Rhizomania). Phloem tissue often becomes necrotic and appears as dark rings in cross sections or dark streaks in longitudinal sections of the root.

MANAGEMENT

The California Department of Food and Agriculture conducts a statewide control program aimed at reducing the overwintering population of beet leafhopper in the foothills on the west side of the San Joaquin Valley. Control efforts, consisting of treatments with the insecticide malathion, occur primarily at three periods: in fall to reduce the overwintering population; in winter to control adult females before egg laying begins; and in spring to reduce the population before migration back to sugarbeet occurs. Weed control in areas surrounding the field can help reduce sources of beet curly top inoculum.

Biological Control
Attempts have been made to introduce several leafhopper parasites. To date, these parasites are not well enough established to provide natural control. It is hoped, however, that with time they may become effective in regulating leafhopper populations.

Cultural Control
Removal of weeds and volunteer beets surrounding sugarbeet fields can play an important role in reducing sources of inoculum available to migrating leafhoppers.

Monitoring and Treatment Decisions
Foliar insecticides have not proven to be generally effective in controlling beet leafhopper and reducing the incidence of beet curly top virus when applied directly to the sugarbeet crop. Occasionally systemic insecticides have proven valuable in reducing the incidence of this virus. The effectiveness of these materials depends on the climatic factors affecting weed hosts of the leafhopper and the virus, timing of planting and application of materials relative to leafhopper migration, proximity of fields to leafhopper/virus overwintering sites, and the success of state programs to reduce leafhopper populations.

Common name		Amount/Acre	P.H.I.+
(trade name)			(days)
Note: These materials have been successful in reducing damage from beet curly top virus in research settings, but their efficacy under field conditions cannot be guaranteed.
When choosing a pesticide, consider information relating to water quality and impact on natural enemies and bees.
A.	IMIDACLOPRID
	(Gaucho) 480, 600	Label rates
	MODE OF ACTION: A neonicotinoid (Group 4A)1 insecticide.
	COMMENTS: A seed treatment.
B.	PHORATE*
	(Thimet) 20G	4.5 oz/1000 row ft	30-at planting
		or 4.9-7.5 lb	30-postemergence
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Do not place phorate granules in direct contact with seed. Do not feed tops or silage to dairy cattle. Place granules to the side of seed or in a band over the row. Do not apply by air or make more than 2 applications/season.
C.	ALDICARB*
	(Temik) 15G	7-14 lb	90
			120-if tops are to be fed
	MODE OF ACTION: A carbamate (Group 1A)1 insecticide.
	COMMENTS: See label for specific instructions. Use at planting or as postemergent side dressing. Do not exceed 28 lb/acre.
+	Preharvest interval. Do not apply within this many days of harvest.
1	Modes of action are important in preventing the development of resistance to pesticides. 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. 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 is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
*	Permit required from county agricultural commissioner for purchase or use.

PUBLICATION

UC IPM Pest Management Guidelines: Sugarbeet
UC ANR Publication 3469
Insects and Mites
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
D. R. Haviland, UC IPM Program, Kern Co.
L. D. Godfrey, Entomology, UC Davis

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