. California greenhouse pests and their control. Insect pests; Greenhouse plants. black head. When mature they are about 1/4 inch long. The adults are slender, blackish gnats, about 1/8 inch long. They run rapidly over the foliage, soil, and windows. Development: Eggs are laid in the soil. Hatching takes place in about one week, and the maggots feed for about two weeks. A transformation stage is then passed in the soil which lasts about 1 week. Each female lays about 100 eggs. CONTROL Fungus gnats are effectively controlled with certain of the newer organic com- pounds. 1. DDT: effective for a
. California greenhouse pests and their control. Insect pests; Greenhouse plants. black head. When mature they are about 1/4 inch long. The adults are slender, blackish gnats, about 1/8 inch long. They run rapidly over the foliage, soil, and windows. Development: Eggs are laid in the soil. Hatching takes place in about one week, and the maggots feed for about two weeks. A transformation stage is then passed in the soil which lasts about 1 week. Each female lays about 100 eggs. CONTROL Fungus gnats are effectively controlled with certain of the newer organic com- pounds. 1. DDT: effective for adults. (See page 52.) 2. Chlordane: excellent control of mag- gots and adults. (See page 51.) 3. Benzene hexachloride: effective for maggots and adults. (See page 50.) GALL MIDGES Importance: Gall midges comprise a large group which contains a number of important pests of ornamental plants. They generally make characteristic galls on the foliage or deform the buds and flowers. Several species, such as the rose midges, violet midges, and orchid midges, are important greenhouse pests in other parts of the country, but these have not been observed in California. The chrys- anthemum gall midge, however, is a com- mon and persistent pest. Some species of gall midges are fungus feeders, and those belonging to the genus Mycophila in particular, have been ob- served in numbers in greenhouses, breed- ing among flower pots. These do no damage. Other species are beneficial, the larvae preying on destructive midges, mites, aphids, mealybugs and other scale insects. Several of these have been ob- served in California greenhouses. I ,. â Fig. 47. Galls of the chrysanthemum gall midge on chrysanthemum leaves. r 381. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Pritchard, A. Earl (Arthur Earl), 1915-1965. Berkeley, Cali
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