About Potato Leafhopper
Reproduction and Life Cycle
This is a migrating pest. Typically, the migrating adults are largely female. The ratio is usually 25:1 in farmers’ alfalfa fields after the migration is completed in May. The females all carry fertilized eggs, which they will place in leaf veins and plant stems (the most succulent tissue) as soon as they find alfalfa or other suitable host plants. This process occurs most during the night and if temperatures are above 65 degrees Fahrenheit. Each female adult will lay on average 3 eggs each day or anywhere from 30 to 200 throughout their lifetime. For an egg to hatch, it will take between 9 and 11 days. The newly hatched nymphs will transform through 5 instar stages. It will take approximately 15 days to complete. When the adult emerges, mating will usually occur within 2 days. About 3 days later, the female will lay her eggs. The reproductive life for females is about 30-35 days and for males is around 33 days. By midseason, the ratio of females to adults will revert back to 1:1. There are often 3 or 4 generations annually.
Potato Leafhopper Identification and Habitat
Adult potato leafhoppers are an active insect and will fly above plants if disrupted; the wingless nymphs will move from side to side. A fully grown adult is light green with six white dots in a row, located on their back behind the head (usually can only be seen with a magnifier). They are about 3mm long and have a wedge-shaped body. Potato leafhopper eggs are gooey and clear. Nymphs in the first stage of development have no colour with red spots that will fade as they mature. Soon they will take on a yellow shade. Once they reach the third instar they will appear pale green.
The potato leafhopper is a pest to over 200 wild plants, cultivated crops, and legumes. They migrate during the winter, usually to the states that are along the Gulf of Mexico, or the southern states that fall along the Atlantic Ocean. This is due to the fact that the frigid northern states would kill this pest during winter. Late in May, storms will develop in the Gulf and will transport the potato leafhopper back to the Pennsylvania area. However, the larvae will not migrate since they do not have wings and thus cannot glide into updrafts.
When a leafhopper feeds on a plant, the result is referred to as “hopperburn”. They will move its stylets through the plant cells, using a feeding style referred to as lacerate-and-flush, which can help this pest collect the plants juices. They tend to prefer feeding from a leafs underside. A combination of the saliva introduced to the plant and the wounding of cells will effectively damage the plant since tiny tubes in the plant will be blocked so that nutrients will not be effectively distributed throughout the plant. Hopperburn symptoms include browning and cell injury in potato plants, curling leaves and stunted growth and lower yield in bean plants, and a V-shaped wedge that is yellow in colour on alfalfa plants. Hopperburn can be especially devastating to crops when the conditions are very dry as this puts even more stress on the plant. Usually by the middle of August adult leafhoppers will stop reproducing and populations begin to decrease. You can also use a sweep net to catch potato leafhoppers in order to understand how extensive the infestation is.
Potato Leafhopper Management and Control Methods
Harvesting your alfalfa with an early cutting (usually by about 5 days) can be an effective way to control the potato leafhopper as the harvest will kill eggs, nymphs, and possibly the adults. If it does not kill the adults, it will at least help to drive them out of the field. There are also some plant varieties available that are resistant to leafhoppers that have potential for very similar yield amounts to that of the nonresistant varieties. Note that having satisfactory control is often dependent on using an integrated management system that includes the use of cultural and chemical methods.
It is important that you only use a chemical control method if the potato leafhopper population is above the economic threshold, but before too many plants are damaged; in this case there will be no point in using the insecticide. If the infestation occurs after the alfalfa plant grows 14 inches or taller, there will be no effect on the yield, meaning insecticides will also be unnecessary. When you do need chemical control, some products that have been known to be effective are Baythroid XL, Dimethoate 400, Lorsban Advanced, Mustang MAXX 0.8 EC, Warrior II, and Tombstone 2 EC. Be sure to carefully read the label for cautions and proper application.
Latin / Alternative Potato Leafhopper Names