Forages: Potato Leafhopper

Excerpt from Agronomy Guide for Field Crops (Chapter 5)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Description
2. Life History
3. Damage
4. Scouting Technique
5. Action Thresholds
6. Management Strategies
7. Updates on Forages: Potato Leafhopper
8. Related links...

Description

The potato leafhopper (PLH) adult is a pale green, wedge-shaped, winged insect about 3 mm long with piercing and sucking mouthparts. It is most broad towards the head, tapering evenly to the wing tips. It has a row of six rounded, white spots behind the head. Nymphs are smaller than adults are and wingless.

Plate 56. Potato leafhoppers are pale green, wedge-shaped, winged insects. Immature numphs are smaller and wingless.

| Top of Page |

Life History

PLH do not overwinter in Ontario, but migrate north every spring, carried by southerly, low weather fronts that start in the Gulf of Mexico. Adults may arrive in late spring and begin sucking on plant juices. Females lay their eggs in the tissue of main veins and petioles of leaves. Development from egg to adult takes approximately 4 weeks.

Damage

Damage is most severe in new seedlings and in young regrowth. While potato leafhopper nymphs and adults suck juices from plant foliage, they inject a protein that blocks veins. This causes the edges to become yellow and puckered, with a characteristic yellow "V" shape beginning at the tip of the leaves. When severe, the leaves appear burned, which is called "hopperburn". PLH can cause a 2%-3% reduction in the percentage of protein, in addition to reducing both the average height and yield. Border areas are usually affected first. Leafhoppers tend to come into soybean and edible bean fields after neighbouring alfalfa fields are cut. The symptoms of potato leafhopper are commonly confused with herbicide injury problems and nutrient deficiency. Most of the damage occurs from June to mid-August. High risk factors include hot, drier-than-normal seasons.

Plate 94. Potato leafhopper injury is most severe in new seedlings and in young regrowth.

| Top of Page |

Scouting Technique

Take 20 sweeps from five areas of the field beginning in late June. Avoid field edges. Determine the average number of PLHs per sweep. Next, take 20 alfalfa stems at random and record the average plant height. See the section Scouting Tools and Techniques, for a discussion of the sweep net method.

Action Thresholds

| Top of Page |

Management Strategies

Resistant varieties are available that use glandular hairs as the resistance factor. These glandular hairs, both on the leaves and stems, act as mechanical barriers to PLH feeding. Cutting alfalfa early will potentially reduce egg, nymph and adult populations. A naturally occurring fungal pathogen helps reduce the populations of the PLH under cool, moist conditions. Predators and parasites appear to play a minor role in controlling the pest. If populations exceed the action thresholds, an insecticide may be necessary. Refer to OMAFRA Publication 812, Field Crop Protection Guide, for insecticide information. It should be noted that spraying insecticides on alfalfa will also kill beneficial insects, the natural enemies of PLH, alfalfa weevil and lygus bug. (Order OMAFRA Publication 812, Field Crop Protection Guide)

| Top of Page |

Updates on Forages: Potato Leafhopper

• Field Crop Protection Guide - Publication 812
  • Forages: Potato Leafhopper

| Top of Page |

Related links...

• Insects
• Forages

| Top of Page |