Agriculture: Alfalfa Pest Management Guidelines

Pests in Seedling Alfalfa

Keep records of pests you see to help choose a seedling variety for next year’s alfalfa planting and to implement proper equipment sanitation. Names link to more information on identification and management.

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Damping off diseases Identification tip: Roots and leaves rot due to seedling diseases (damping off).	Downy mildew Identification tip: Spots on upper sides of infected leaves are gray-green to tan.
Sclerotinia rot Identification tip: Hard black sclerotia resting bodies form on the mat of white mycelium.	Stem nematode Identification tip: Plants infected with stem nematodes have dead stem buds, stunted shoots, and swollen internodes.
Cutworms Identification tip: Caterpillars are about 1.5 to 2 inches long and appear smooth-skinned with various colors and patterns. Larvae frequently roll into a C shape when disturbed.	Aphids Identification tip: Four aphids commonly cause damage in alfalfa hay. To identify cowpea aphid, pea aphid, blue alfalfa aphid and spotted alfalfa aphid, see “Identifying aphids”.

Text Updated: 11/06