Aphid, Asparagus
Asparagus aphids are small, oval, green to gray aphids that may be covered in a waxy secretion.
Male and female adults are produced in September and October and will mate and lay eggs on the lower portion of the ferns. Eggs hatch in the spring, go through 4 nymphal instars and then develop into stem mothers, capable of producing up to 55 live female nymphs within 20 days. There are many generations each season.
Aphid feeding causes a shortening of the internodes and a rosetting or brush-like appearance of the foliage, especially near the tips of the lower branches. High aphid populations will reduce plant vigor and yield or kill seedlings. A combination of infestations and cold winters can kill even full size crowns within two years.
Watch for abnormal plant growth on the lower portion of the fern.
There are many natural enemies that help keep the aphid populations in check during the season including; lady beetles, lacewings, predatory midges, flower fly larvae, the Braconid wasp, Diaeretiella rapea, and parasitic fungi.
A combination of removing dead ferns during the fall or winter and spring tillage will usually control this pest.
Treating the ferns twice, about 10 days apart, with a systemic insecticide (i.e. dimethoate) will provide effective control if naturally occurring bio-controls prove insufficient.
For Current information on production methods (including varieties, spacing, seeding, and fertility), weed, disease, and insect management, please visit the New England Vegetable Management Guide website.
Identifying and Enhancing Natural Enemies in Vegetable Crops
Insects
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