How to Manage Pests

UC Pest Management Guidelines

Sugarbeet

Beet Leafhopper

Scientific name: Circulifer tenellus

(Reviewed 11/05, updated 1/10)

In this Guideline:

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 and other related viruses. 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

Weed control in areas surrounding the field can help reduce sources of Beet curly top virus inoculum.

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 or 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, and proximity of fields to leafhopper and virus overwintering sites.

Common name		Amount/Acre	R.E.I.+	P.H.I.+
(trade name)			(hours)	(days)
The following materials are listed in the order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees as well as the environmental impact. Not all registered pesticides are listed. Always read the label of the product being used.
A.	PHORATE*
	(Thimet) 20G	4.5 oz/1000 row ft	72	30–at planting
		or 4.9–7.4 lb		30–postemergence
	MODE OF ACTION GROUP NUMBER1: 1B
	COMMENTS: Has been successful in reducing damage from Beet curly top virus in research settings, but efficacy under field conditions cannot be guaranteed. 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 one applications/season.
+	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.
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 more information, see 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

E.T. Natwick, UC Cooperative Extension Imperial County
Acknowledgement for contributions to Insects and Mites:
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
D. R. Haviland, UC IPM Program, Kern County
L. D. Godfrey, Entomology, UC Davis

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