This section is from the book "Vegetable Gardening", by Ralph L. Watts. Also available from Amazon: Vegetable Gardening.
The Cabbage Maggot (Pegomya Brassicae) was introduced from Europe early in the nineteenth century. It feeds upon various cruciferous plants, but is espedaily troublesome to cabbage and cauliflower. Chittenden ("Insects Injurious to Vegetables," p. 132) claims that the insect has been on the increase since 1902.
* American Agriculturist.
The adult resembles the common house fly, but is considerably smaller. It begins laying eggs early in spring, depositing them on or near the stems of the young plants. Slingerland observed that the fly makes its first appearance on Long Island the latter part of April, and that larvae were first seen in early May. From 4 to 10 days are required for hatching. The larva or maggot is footless, shining white, sometimes tinged with yellow and when full grown is 0.32 of an inch long. It prefers feeding on the young tender rootlets, but also erodes and girdles the stem of the plant, often boring into the lower part of the root. It pupates within its own hardened skin in soil about infested plants. The time required for pupation is from 15 days to 3 1/2 months. A second brood emerges about the middle of June and changes to puparia in July. The life history from this time is unknown, but it is thought that the insects pass the winter as maggot, pupa and fly.
Numerous remedies are recommended, but one of the best is to place card disks about the plants before egg laying begins. (Cornell Station Bulletin 78, pp. 481-574). Although effective, the making and placing of these cards is tedious and the plan is not generally popular with extensive growers. Carbolic acid emulsion (133) is the most practical means of controlling the pest. It should be diluted about 30 times and applied by spraying on the stems of the plants before egg-laying begins, and repeated if necessary. Experiments made at Geneva, N. Y. (New York Station Bulletin 301), show that growing the plants in frames covered with cheesecloth is a satisfactory method of protection before transplanting.
plants, crops, gardening, cultivated, harvesting, food ,greenhouses, fertiliser, vegitables