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 per acre | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used. | ||||
| A. | PHORATE* | |||
| (Thimet 20G), at planting | 3.4–4.5 oz/1000 ft row | 72 | 30 | |
| (Thimet 20G), postemergence | 4.9–7.5 lb | 72 | 30 | |
| 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 application per season. | ||||
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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 | Group numbers for insecticides and miticides are assigned by IRAC (Insecticide Resistance Action Committee). Rotate pesticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. |
| * | Permit required from county agricultural commissioner for purchase or use. |