Other diseases Common leafspot, lepto leafspot and blackstem are foliar diseases that cause leaf losses and reduce both total alfalfa yield and quality. Fusarium wilt and verticillium wilt are diseases that have not caused severe problems in Nebraska. Varieties listed in Table I have been developed with resistance to some of these diseases. Select varieties that have resistance to anthracnose, phytophthora root rot and bacterial wilt. Resistance to Insects Insects can cause losses in hay yield and quality, stand establishment and persistence.
Several varieties have low to moderate resistance or tolerance to potato leafhopper yellowing.
Varieties with high levels of resistance to pea aphids or spotted alfalfa aphids, or both, are available. Alfalfa Yields Varieties that have been tested since 1991 for two or more years at locations in Nebraska and marketed in the state are shown in Table I . Data collected from these varieties since 1978 are included in the table. Yield comparisons are relative to production from the check varieties Vernal and Wrangler included in the same tests. A yield of 115 percent indicates that the variety produced 15 percent more yield than the average yield of Vernal and Wrangler.