CROPLAN Alfalfa Seed Resistance

Anthracnose Disease

· A severe stem and crown disease that causes defoliation. Multiple races, including a new race 5, can be present in late season.

· Varieties are now available with multi-race high resistance.

· It occurs most often under warm, moist conditions.

· I t causes yield loss of up to 25%.

· Susceptible plants have large, sunken oval- to diamond-shaped lesions.

· Lesions can enlarge to girdle or kill plant. Girdled stems can exhibit a shepherd’s hook.

Aphanomyces Root Rot Disease

· Causes seedling stunting, reduced nodulation and poor root development.

· Race 1 is widely identified in the U.S.

· Race 2 is in more isolated areas of the Midwest, East and pockets of the Pacific Northwest.

· New race 2/3 is a more severe pathogen found in the same areas as race 2.

· Varieties are now available with multi-race high resistance.

· Commonly found in saturated, poorly drained and/or compacted soils.

Aphids

· Can be a problem in dry periods; controlled by other predators in cool and/or wet periods.

· The blue aphid is the most damaging in the Southern Plains to the Southwest.

High-Salinity Soils

· There are three methods to determine tolerance: the petri dish germination test, the forage greenhouse test and the field test. Salt-breeding nurseries provide varieties with more predictable performance for on-farm potential.

· Soils vary. Saline: high soluble salts. Sodic: high sodium ion content. Alkaline: soil pH that is higher than optimum (pH>8.0).

· Commonly found in the western half of the U.S.

Nematodes

· Microscopic roundworms (several identified species) that live in the soil, surface irrigation water, alfalfa roots and crown tissue.

· Can reduce yield and stand life and cause secondary infections from other diseases. Control them by planting a high-resistance alfalfa variety.

· Commonly found throughout most of the West and Plains.

Potato Leafhopper (PLH)

· Small, light-green insect that feeds on alfalfa plants, causing leaf tips to display a V-shaped yellowing.

· Varieties with glandular hairs provide natural non-preference feeding for PLH.

· Commonly found in the Plains, Midwest and East; most severe in new seedings and summer regrowth that causes yield reduction.