Potato leafhoppers have been in local fields for some time now, though generally at tolerable levels. A few exceptions have been alfalfa fields after the first cutting which required treatment. They arrive each year following migration of the leafhoppers from southern states where they overwinter. Leafhoppers can be found in our alfalfa, soybeans and dry beans. Potato is another crop where their numbers often increase.

The small (1/8 in.), pale green, wedge-shaped winged adults (Figure 1) move rapidly by jumping. Sweep nets are useful for confirming their presence in a field. Adults and nymphs can both be found in fields. The nymphs are paler green, lack wings, and characteristically walk sideways when disturbed on the leaf surface. The nymphs can be found on the undersides of the leaves. The nymphs are generally more damaging than the adults since they feed for several weeks on the leaves where they hatch. Adults move around much more.

Feeding injury by potato leafhoppers results in a symptom called "hopperburn". The visual symptoms include leaves changing from green to yellow to brown as they deteriorate. When leaf injury is present, plant growth is impaired. Control of potentially damaging populations should not be delayed to the point where damage symptoms are visible.

In alfalfa, potato leafhoppers that arrive early can cause problems with regrowth after the first cutting is complete. Monitoring regrowth with the use of 15 inch sweep nets to detect adults and/or nymphs is highly recommended. Treatment guidelines are provided in Table 1.

Insecticides approved for use to control leafhoppers in alfalfa include: permethrin*, Baythroid*, carbaryl, dimethoate EC (Cygon, De-Fend), Furadan*, Lannate*, Lorsban, Malathion 57 EC, Mustang Max*, Proaxis* and Warrior*.