A field research project, to compare the effect of alfalfa/grass mixtures with pure alfalfa stands, on potato leafhopper populations, was planted May 1, comparisons included a standard alfalfa variety with 1 lb. of orchardgrass and with 2 lb. of orchardgrass, standard alfalfa alone. (control), and a reputed potato leafhopper resistant alfalfa variety. These 4 plantings were randomly replicated 4 times for a total of 16 plots. The seeding appeared to have a good start but was adversely affected by extremely wet weather throughout June, particularly when more than 10" of rain was received the last week of June.

A decision was made to renovate that stand in a manner that would disrupt the original research objectives, so a completely new seeding was done at a nearby location. The original plan was used in the seeding on August 16, following wheat harvest and straw removal.

The soil was tilled twice to level the seedbed, hill existing weeds and volunteer wheat, and to incorporate fertilizer. An excellent stand was established, despite very dry conditions 2 weeks after the planting date.

No data was taken to date, although it was observed that the PLH resistant variety appears to germinate in cool wet conditions (spring planting) better than in hot dry conditions, relative to the standard (control) variety.

If the stand survives the winter, comparison of the plots will begin in 1994, with PLH populations, yield and palatability records gathered for 2nd and subsequent cuttings. The research project is planned for a 3 to 5 year period, depending on the vitality of the stand.

Potato Leafhopper (PLH) is the insect causing the most damage to alfalfa in the Midwest and as a result demands the highest use of insecticides. Alternative strategies to control the pest are critically needed. Some experimental evidence suggest that growing grass in mixture with alfalfa may reduce PLH populations and the resulting damage sustained by the crop.

This type of research has not been done at all in Ohio and only in small plots elsewhere. The plants are planted on land involved in the Lake Loramie Water Quality Incentive Project (WQIP) and could result in reduced insecticide use.

Field sized replicated plots to compare infestations of PLH have been planted, not small research areas previously utilized in other studies. Large plots are critical to accurately assess the impact of control strategies on PLH populations because of their mobility.

PLH population variations, yield checks, and economic analysis of all factors will be evaluated and utilized for Extension publications, newsletters, field day presentations and journal articles.

The potato leafhopper is the most serious insect pest of alfalfa in the Midwest and therefore requires the greatest use of pesticides for control. Since alfalfa is the most important forage crop in the Midwest and little or no resistance to PLH is evident in varieties, the use of grass seeded with alfalfa may provide a cultural practice to farmers, enabling them to produce a forage crop similar to pure alfalfa in feed and market value, with reduced inputs and impact on the environment. Evaluation of the proposed project will provide valuable insight for analysis of this cultural practice.

Accessing the WQIP activities in the Lake Loramie watershed utilizes long term commitments in the area.

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