The early spring-like weather has excited both home gardeners and vegetable growers. It has given everybody a chance to get an early start on all activities, including planting some early season crops. Take note, though, we are not the only ones to take advantage of this nice weather and early season crops. Several flies of the Delia species are causing some problems in crops planted the past couple of weeks.
These are not mid-summer pests as they thrive in cool spring weather which we have had the past several weeks. There are several flies in this grouping such as the seedcorn maggot and bean seed maggot, but most have a similar life cycle. The fly overwinters in the soil as a pupae and will emerge in the spring at which time large groupings of flies can be found flying over freshly cultivated fields. These flies look very similar to the common house fly. After mating, the female lays her eggs in soil that is high in some type of organic matter (decaying cover crop or field that has received a manure application). Within several days the eggs hatch and the maggots start looking for food.
The problem occurs when vegetable seeds or seedlings are planted in the same soil that contains the maggots. They have the ability to seek out and burrow into the seed or tunnel into the stem of an emerging seedling and greatly reduce the plant's chance of survival. Not a picky eater, these maggots can feed on peas, beans, corn, cabbage, turnip, radish, onion, beet, spinach and sprouting potato. Damage was observed in recently-planted onion fields in Clinton County where greater than 50 percent of the plants were affected.
This is a tough pest to control and options are somewhat limited, especially for the homeowner. Cultural controls include thorough incorporation of organic matter into the soil, preparation of seedbeds for rapid germination, shallow planting (encourage rapid plant growth and minimize the time the germinating seed is sitting in the soil) and planting when soil temperatures are warm. Vegetable growers have the option of also using insecticide-treated seeds or placing an insecticide in the soil at planting time.
Clinton County Master Gardener Symposium
If you are into gardening, you should take every opportunity to learn something new. The Clinton County Master Gardeners are providing some great talks in our backyard with their Clinton County Master Gardener Symposium on April 21.
Topics include how to grow orchids, plant by the moon and edible landscaping. For $40, which includes lunch, you can attend the Clinton County Master Gardener Symposium. The symposium will be held at the Penn State Extension Office near Lamar. Pre-registration is required in order to reserve your seat and lunch. Call Penn State Extension at 726-0022 or stop by and register.