The Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz. released Aug. 7, 2013.

Insect pests at stand establishment in fall melons and produce

By John Palumbo, UA research scientist and Extension specialist

Growers have begun planting fall melon crops and produce planting is a few weeks away. Pest control advisers are likely to find many insects with the potential to cause serious economic losses to seedling crops during stand establishment.

These include flea beetles, crickets (sometimes grasshoppers), darkling and rove beetles, and saltmarsh caterpillars. These insects have chewing mouthparts. Most can consume large amounts of leaf tissue in a short time.

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Seedling crops at the cotyledon stage are most susceptible to these pests. Feeding by large numbers can devour much of the cotyledons or outright kill small plants.

If left uncontrolled, larger seedling plants (2-4 leaf stage) can sustain significant feeding damage on terminal growing points or newly emerged leaves. Not only can this feeding stunt plant growth, it can result in the lack of uniformity and maturity at harvest.

Host sources of flea beetle, cricket and ‘wooly worm’ infestations include numerous summer crops (e.g., sudan grass, cotton, and alfalfa) and a large host of weeds (e.g., purslane).

Experience suggests that melon fields planted adjacent to these crops and weedy areas are at a high risk of these seedling pests, particularly flea beetles. As these summer host plants are harvested or terminated over the next few weeks, seedling pests typically move to the next available host crop - lettuce, cole crops, and melons.

Fortunately, many registered insecticide alternatives are available that can be applied via sprinkler chemigation (i.e., pyrethroids) or foliar sprays (i.e., Lannate, neonicotinoids) that can cost effectively minimize the insect abundance and damage to emerging crops.

For more information on insect pests of leafy vegetables and melons at stand establishment, click on thislink.

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