Beet leafhopper (Circulifer tenellus)
Other leafhoppers (Empoasca spp., Ceratagallia spp., Macrosteles quadrilineatus)
Pest description and crop damage The most important leafhopper pest for hemp producers in the PNW is the beet leafhopper (Order: Hemiptera; Family: Cicadellidae) mainly due to its ability to transmit the beet curly top virus. To learn more about the epidemiology and symptoms of beet curly top virus on hemp, check out this information (link: https://pnwhandbooks.org/plantdisease/host-disease/hemp-cannabis-sativa-...) from Pacific Northwest Plant Disease Management Handbook. This leafhopper varies between 0.13 to 0.14 inches in size, and within different shades of yellow in color. It can be recognized from other similar leafhopper for the absence of head markings. See Potato, Irish chapter for more details. In addition, a wide diversity of other leafhoppers (e.g., Empoasca spp., Ceratagallia spp., and M. quadrilineatus) can be found in hemp fields. These leafhoppers are small, pale green, and torpedo-shaped. However, their ecological roles in hemp are unknown.
Biology and life history Beet leafhopper can feed and reproduce in many wild hosts (e.g., kochia, Russian thistle, tumble mustard, pigweed, lambsquarters, and groundsel) and crop hosts (sugar beet, potato, carrot, tomato, and cucurbits). In early spring, the beet leafhopper adults move into crop fields from overwintering sites to search for suitable hosts. Females deposit whitish to yellow colored elongated and slightly curved single eggs in the tissue of the leaves and stems. Under optimal conditions, each female can lay 300-400 eggs in their life cycle. Young leafhoppers (nymphs) are transparent to white but become yellowish within a few hours; later they can show black, red, and brown spots on the body. Both nymphs and adults show high mobility and jump away when disturbed. In Oregon and Washington, the leafhopper generally completes three generations per year.
Scouting and thresholds Monitoring of beet leafhoppers is recommended to evaluate population dynamics. An efficient method to monitor is by using yellow sticky cards placed on the edge of the field. As other species of leafhopper are regularly present in hemp fields, it is important to correctly identify the beet leafhopper.
Beet leafhoppers and other leafhoppers are preyed on by generalist predators such as green lacewings, spiders, assassin bugs, and big-eyed bug, and can be parasitized by several wasp belonging to the families of Mymaridae and Trichogrammatidae, and flies belonging to the family Pipunculidae.
Managing the favorite weed hosts (e.g., kochia, Russian thistle and tumble mustard) of beet leafhopper is probably the most important cultural management option although sometimes unpractical.