Potato Leafhopper
Beginner
Scientific Name
Empoasca fabae
Identification
Life Stages: eggs, nymphs, adults.
Adults are small, pale green, about 3 mm long and wedge-shaped, with a broad head and thorax. The body tapers along the wings. Leafhoppers are very active and quick to fly.
Nymphs are similar to adults but lack fully developed wings. Nymphs pass through 5 stages, increasing in size until the adult stage is reached in about 2 weeks. When disturbed, nymphs run sideways like crabs over the edge of the leaflet to the underside.
Often Confused With
Wingless aphids. Leafhopper nymphs move fast and walk sideways. Aphids walk very slowly.
Period of Activity
Potato leafhopper can arrive in Ontario as early as May. The potato leafhopper feeds on alfalfa before moving into other vegetable crops.
Scouting Notes
Leafhoppers migrate into potatoes in early summer after alfalfa is cut. Check potato fields very closely once haying starts.
While nymphs are best monitored by examining potato leaves, adult leafhoppers should be caught with a sweep net. A minimum of 25 sweeps at several locations is necessary. Each sweep consists of a single pass that just touches the top of the potato canopy but does not injure the plants. Empty the net into a plastic bag and make a note of the number of leafhoppers in the net at each site.
If you are not using a sweep net, approach the selected sites slowly and count the number of adult leafhoppers that you see in the site either flying or on the leaves.
Nymphs can be monitored at the same sites selected for CPB. At each site, count the nymphs on one leaf from each of 5 plants. Early in the season examine leaves from the mid-section or lower half of the plant. In July and August, examine only green leaves, not yellowing leaves, for nymphs. Report the number of immature nymphs on 50 leaves.
Do not confuse leafhopper nymphs with aphids. Leafhopper nymphs move fast and walk sideways. Aphids walk very slowly.
Thresholds
1 or more adults per sweep and/or 20 nymphs per 50 leaves or 15 adults per 50 leaves.
Advanced
Scientific Name
Empoasca fabae
Identification
Life Stages: eggs, nymphs, adults.
Adults are small, pale green, about 3 mm long and wedge-shaped, with a broad head and thorax. The body tapers along the wings. Leafhoppers are very active and quick to fly.
Nymphs are similar to adults but lack fully developed wings. Nymphs pass through 5 stages, increasing in size until the adult stage is reached in about 2 weeks. When disturbed, nymphs run sideways like crabs over the edge of the leaflet to the underside.
Often Confused With
Wingless aphids. Leafhopper nymphs move fast and walk sideways. Aphids walk very slowly.
Biology
The potato leafhopper does not overwinter in Ontario. It is carried by upper-level winds from the United States and can arrive in Ontario as early as May. Depending on weather conditions, 2–4 generations can develop during the season. Usually two generations develop if the season is cool. By contrast, up to 4 generations have been observed in warm years.
Although the potato leafhopper attacks many crops, alfalfa is the preferred host. Alfalfa cutting sends adults flying to infest other crops. This explains why populations of leafhopper increase so rapidly in potato fields. Potato fields adjacent to alfalfa fields are at high risk of leafhopper infestation.
Adults and nymphs feed by sucking sap from the leaves and stems. Initially, the feeding damage causes yellowing and browning of the tips and margins of the leaves. Later, the leaf margins roll inward, resulting in the typical hopperburn damage. Usually, hopperburn is noticeable 4 to 5 days after leafhopper feeding. To avoid yield losses, leafhoppers must be controlled before hopperburn is visible.
Period of Activity
Potato leafhopper can arrive in Ontario as early as May. The potato leafhopper feeds on alfalfa before moving into other vegetable crops.
Scouting Notes
Leafhoppers migrate into potatoes in early summer after alfalfa is cut. Check potato fields very closely once haying starts.
While nymphs are best monitored by examining potato leaves, adult leafhoppers should be caught with a sweep net. A minimum of 25 sweeps at several locations is necessary. Each sweep consists of a single pass that just touches the top of the potato canopy but does not injure the plants. Empty the net into a plastic bag and make a note of the number of leafhoppers in the net at each site.
If you are not using a sweep net, approach the selected sites slowly and count the number of adult leafhoppers that you see in the site either flying or on the leaves.
Nymphs can be monitored at the same sites selected for CPB. At each site, count the nymphs on one leaf from each of 5 plants. Early in the season examine leaves from the mid-section or lower half of the plant. In July and August, examine only green leaves, not yellowing leaves, for nymphs. Report the number of immature nymphs on 50 leaves.
Do not confuse leafhopper nymphs with aphids. Leafhopper nymphs move fast and walk sideways. Aphids walk very slowly.
Thresholds
1 or more adults per sweep and/or 20 nymphs per 50 leaves or 15 adults per 50 leaves.
Management Notes
Insecticides registered for potato leafhoppers usually provide good control of this pest. The potato leafhopper has not developed resistance to insecticides yet. Field scouting is essential to time insecticide applications.
