There are many insects under the umbrella term of “leafhoppers” of which the two that are economically important to potato growers are the aster leafhopper (Macrosteles quadrillineatus) and the potato leafhopper (Empoasca fabae). These are pests throughout the US mid-west and southern Canada. Among entomologists, the leafhopper ranks third as the most important insect pest in North America, after the Colorado potato beetle and green peach aphid. Of the two leafhoppers above, the potato leafhopper has the most effect on yield reduction.
Potato leafhopper (Empoasca fabae) damages crops through direct feeding on the sap. It is a piercing-sucking insect that causes injury referred to as “hopperburn.” This is characterized by necrosis of leaflets starting at the tips and margins resulting, with progress, in defoliation.
Adult potato leafhoppers are wedge or spindle-shaped, and about an eighth of an inch long. They appear bright lime-green to yellow green with white markings. Wings are transparent green and are folded back when at rest. They have a variable number of white spots on top of their head and along their thorax. Nymphs are similar to adults but are smaller and wingless. Several nymphal stages occur in the generation.
Potato leafhoppers overwinter as adults between southern Louisiana and northern Florida. They fly north in the spring on the winds in the upper atmospheric levels. They are mostly found in Wisconsin and Illinois during the growing season. However, in some years, they have been identified as far west as the Panhandle of Nebraska and as far east as Maine.
Adults live 30-40 days but may live as much as 90 days. Two to three small white eggs are laid per day onto stems or large leaf veins, and 200 eggs per adult life is possible. Potato leafhoppers will lay eggs on potatoes. Eggs hatch in ten days forming the first of several nymphal stages. Nymphal stages are short and within 12 days of hatching the nymphs will become adults. Adults are able to lay eggs six days later. Nymphs move backwards and sideways in a crab-like fashion and cannot move from field to field. There can be one to three overlapping generations per season in the north-central States.
Potato leafhopper, primarily adults, cause feeding injury to potato plants. They feed on the underside of leaflets. Injury starts with a yellowing along leaflet margins with a slight rolling. This slight injury is soon followed by a gradual browning starting at the leaflet’s tip and margin (hopperburn), and extending basipetally until the leaflet is all dead and desiccated. The browning is due to cellular death or necrosis. Defoliation will occur. The result is a reduction in yield. No effects on tuber quality has been reported by potato leafhopper.
Sustainable Agriculture — Monitoring fields for populations and correctly identifying the leafhopper is essential to good management. There are many leafhoppers that do not damage potato. A threshold for treatment has been established for potato leafhopper as one nymph per 10 leaves. Sample 35 leaves, three to five times in the field.
Chemical Management — Many insecticides will kill leafhoppers. At planting, Admire, Platinum, Thimet and DiSyston are common. Foliar treatments include Actara, Asana, Ambush/Pounce, Baythroid, Dimethoate (formerly Cygon, also used for false chinch bug), Furadan (also used for sand(hill) chafer), Monitor (also used against aphids), Provado, and Thiodan. For gardening, Sevin is recommended
Effect of Seed and In-furrow Treatments on Leafhopper Symptoms on Potato Plants in 2001 at Scottsbluff, NE.
1 Maxim MZ treatments applied at 8 oz/cwt, Tops MZ at 12 oz/cwt, Admire at 1.3 fluid oz/1000 linear feet, and Platinum at 0.55 fluid oz/1000 linear feet.
2 Treatments in columns followed by different letters were significantly different from each other at p=0.05.
Hosts for potato leafhopper besides potato include edible beans especially lima and snap, alfalfa, and soybeans which is not seriously affected. When alfalfa is harvested, adults may move into potato fields; nymphs die of starvation.
Quick Review / Potato Leafhopper
Adults - bright green, variable white spots, 1/8 inch long
Nymph - like adult but smaller and wingless
Overwinters - Louisiana to Florida
One to three generation/ season in north-central U.S.
Adults - June to early July
Adult - feeding on sap (sucking-piercing insect)
Nymph - same
Monitor and Identify
Economic Threshold = 1 nymph/10 leaves