• With severe or prolonged PLH feeding stress:
  • Leaves turn reddish or bronze.
  • Plants stop growing and appear stunted.

• Adults are yellowish, lime-green, wedge-shaped insects about 1/8 inch long.
• Nymphs are paler in color, smaller in size and lack wings.
• Adults jump or fly when disturbed.
• Nymphs crawl rapidly sideways and hide when disturbed.

• One of the most common and destructive insects affecting alfalfa.
• No reliable method to forecast damage.
• Scouting fields and using a sweep net is the only effective method to monitor PLH activity.
• Once visible symptoms of hopperburn and plant stunting become evident, it is too late for corrective action.
• PLH-resistant alfalfa varieties can simplify and improve management.

• Adults overwinter in the southern/southeastern US.
• Adults migrate to the northern and eastern US in the spring, carried by prevailing weather systems.
• Females deposit eggs into the stems, petioles and leaf veins of alfalfa.
• Eggs hatch in 7-10 days into wingless nymphs that become fully grown winged adults in about 2 weeks.
• Populations greatly increase by early summer.
• Can cause major economic damage on new seedlings and second- and third-cutting alfalfa.
• Optimum temperatures for reproduction and growth are between 70 and 90 degrees F.

• Greatest impact on crop is yield reduction.
• Severe damage can reduce crude protein content, carbohydrate reserves in taproot and plant regrowth.

Chemical Control

• Growers have a choice of several effective insecticides.

Mechanical Control

• Harvesting infected stands may be required.
• Harvesting potentially reduces egg, nymph and adult populations.
• Harvesting severely damaged alfalfa stands may be the only method to initiate regrowth of alfalfa stems.

Thresholds for Treatment

• Scout alfalfa field using a sweep net.
• For non-PLH resistant varieties, spray when leafhopper count per 10 sweeps exceeds average plant height in inches.
• For PLH-resistant varieties, spray when leafhopper count per 10 sweeps exceeds 3X the alfalfa height in inches.

PLH-Resistant Varieties

• Resistance comes from small hairs on the stem that repel the leafhopper.
• Pioneer® brand 55H94 has best-in-class leafhopper resistance when compared to competitor varieties.
• Pioneer 55H94 has outperformed competitors in Pioneer and university trials across multiple locations and years.
• This variety is recommended where intense PLH pressure spans 2 to 3 cuts per year.
• Because not all plants in an alfalfa variety are genetically identical, some plants in a PLH-resistant variety do not carry PLH resistance.
  • Some feeding symptoms may be noticed on non-PLH plants.

Selecting a Resistant vs. Non-resistant Variety

• If scouting and spraying offer adequate control, growers may choose varieties that are not PLH resistant.
• If scouting and spraying does not normally control potato leafhopper, a PLH-resistant variety is a good choice.
• First-year PLH-resistant alfalfa may need chemical control.