Good resistance to aphanomyces root rot race 1 is a bit less common. Aphanomyces is favored by waterlogged soils, so resistance is a good idea on heavier soils, especially in eastern Kansas. Resistance to alfalfa stem nematode is good insurance in southeastern Kansas. Root knot nematode infestations are rare in Kansas so resistance to this nematode is not as important. Resistance ratings for a few other diseases are newly developed and can be found only in company advertisements.
Some companies summerize disease resistance into an overall disease rating index.
The index is the sum of the disease ratings for six important diseases where a high resistance rating gets a score of 5. A perfect disease rating index is 30 points. This system works well since we now have so many good resistant varieties. Keep in mind that several ratings, including stem nematode, are not incorporated in the index. Using a planting time fungicide for certain diseases such as phytophthora and pythium seedling blight is a good idea.