Floriculture Greenhouse Update

Potato Leafhopper

Tuesday, 06 July 2010 08:26

Watch for potato leafhoppers. Leafhoppers are found on many different out-door grown perennials, vegetables and sometimes garden mums. Of the many species of leafhoppers, the potato leafhopper and aster leafhopper are most likely pests on ornamentals in New England. Both adult species have slender bodies and wings that are held roof-like over their body. Leafhoppers jump or fly when disturbed and can quickly move sideways, backwards or forwards. The nymphs resemble adults but lack wings. They have piercing-sucking mouthparts and feed on plant sap, causing yellowing, stunting and loss of vigor.

The potato leafhopper feeds by inserting a needle-like beak into the plant and sucking out the sap. It also injects a toxin as it feeds so leaves may develop a v-shaped brown, edge burn at the tip known as "hopperburn". Photo: hopperburn on Astilbe. This injury may be confused with leaf scorch especially on drought-sensitive Astilbe. Plants may also be stunted with distorted new growth. Growers with retail customers should be aware that potato leafhoppers are building up in beans, potatoes and eggplants now. Damage is worse under drought conditions.

The aster leafhopper transmits the pathogen that causes aster yellows. Other species of leafhoppers may not inject a toxin or transmit diseases as they feed so control may not always be necessary.

Scouting: Brush the leaves of plants with your hand. Small light yellow-green potato leafhoppers dart around and fly up from foliage when disturbed. Tap the foliage over a yellow sticky card or briefly place a sticky card among the plants to catch adults. Potato leafhoppers (Empoasca fabae) adults are approximately 1/8 inch long, and light green with characteristic 6 white spots just behind their head. Once you see adults, look closely at several leaves for nymphs. Nymphs are small, narrow light green wedge shaped insects that move very fast sideways, front and back. Look on the underside of leaves along the leaf vein for the young nymphs especially on Alcea, Astilbe and Dahlia.

Management: The potato leafhopper does not overwinter in New England. It migrates into New England in late April or early May from the south. There may be from 3 to 4 generations per year. Potato leafhoppers also feed on woody plants such as birches, maples and apples. Field crops such as alfalfa, clover and sunflower are also hosts.

Systemic insecticides such as neonicotinoids may be applied to prevent feeding damage when leafhoppers first appear. There are many other pesticides labeled for leafhoppers including azadirachtin, (MOA Group 18) pyrethroids (MOA Group 3), and Beauvaria bassiana(MOA Group M). Pesticides with limited residual will need to be reapplied with good coverage on the undersides of leaves. See the New England Guide for specific pesticides.

Fact Sheet: Leafhopper Pests of Connecticut Nurseries and Landscapes

Leanne Pundt, University of Connecticut
Tina Smith, University of Massachusetts