Effect of Rye Incorporation, Planting Date, and Soil Temperature on Damage to Muskmelon Transplants by Seedcorn Maggot ( Diptera: Anthomyiidae )

Abstract

Seedcorn maggot, Delia platura (Meigen), is an important pest of early-planted melons. Two field experiments were conducted over a 3-yr period to discern (1) the time intervals between incorporation of a rye, Secale cereale L., cover crop and the percentage of muskmelon, Cucumis melo , var. Superstar, transplants killed by seedcorn maggot and (2) the soil temperature that seedcorn maggot injury was not detectable. The 1st objective was accomplished by incorporating a rye cover crop into the soil 2, 1, and 0 wk before muskmelon transplants were set in the field. The 2nd objective was accomplished by transplanting muskmelon seedlings at 4 weekly intervals in 1994 and 1995 and 11 intervals (2–4 d) in 1996. Incorporation intervals did not influence seedcorn maggot injury. In 1994, no plants were killed with any incorporation time, whereas in 1995, a60% of plants in each of the 3 incorporation intervals were killed by seedcorn maggot. Soil temperature proved to be a better indicator of damage potential, as demonstrated in the 2nd trial. When soil temperatures were below 18°C, 30–60% of transplants were killed. However, when soil temperatures were above 21°C, <3% of plants were killed. Soil temperature under black plastic mulch appears to be the most important factor in determining if seedcorn maggots will damage early season muskmelon transplants.