The most recognizable symptom of stem nematodes in alfalfa is patches of stunted plants
with the leaves exhibiting a corrugated appearance. The corrugation is restricted
to areas between the leaf veins. It does not cross veins, as does the corrugation
resulting from thrips damage. Stunted plants usually express thickened or shortened
internodes and can be confused with the symptoms caused by blue aphids. Stem nematode
symptoms are mostly readily observed during early spring regrowth in established alfalfa
Please contact your local county extension office for current information.