Potato Leafhopper in Alfalfa

In both the Ohio State University Extension C.O.R.N. newsletter and the Purdue Pest & Crop newsletter mentions were made of potato leafhopper being a problem in alfalfa. In fact Christian Krupke, John Obermeyer, and Larry Bledsoe of Purdue are reporting large catches of potato leafhopper in their sweeps.  They predict that populations of potato leafhopper will increase as air temperatures rise. From the Purdue newsletter:

Potato leafhoppers are small, wedge-shaped, yellowish-green insects that remove plant sap with their piercing-sucking mouthparts. Leafhopper feeding will often cause the characteristic wedge-shaped yellow area at the leaf tip, which is referred to as “hopper burn.” Widespread feeding damage can cause a field to appear yellow throughout – if you see this visual evidence, the damage is already done and treatment will not help this cutting. Leafhopper damage reduces yield and forage quality through a loss of protein. If left uncontrolled for several cuttings, potato leafhoppers can also significantly reduce stands.

From the OSU Extension C.O.R.N. newsletter:

Sampling is done using a sweep net and taking 10 samples throughout the field. Each sample should consist of 10 sweeps with the net. Count all potato leafhopper adults and nymphs, though over the coming weeks, mostly adults will be seen. When the average number of leafhoppers in a single sample (10 sweeps) is equal to or greater than the average height of the alfalfa stand, insecticide treatment is warranted for varieties not resistant to the potato leafhopper.

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