Radish - Cabbage maggot control
The first generation is the most important to control because plants are small and very susceptible to damage. Natural predators usually provide a good degree of control later in the season as well. Radishes in home gardens can be grown in successive plantings, seeding at weekly intervals--in this way some will avoid damage. Infested radishes should be pulled and destroyed (not composted) if cabbage maggots are present. The best control method consists of preventing the flies from laying eggs. Barriers (row covers) or netting of fine screening can be used for this purpose. In order to be effective, there must be no gaps or tears in the material, the material must be placed over the crop before or immediately upon crop emergence or transplanting, and no hosts of the pests should have been grown on that site the previous year. It is also important to bury the edges of the netting so that flies cannot get under the edges, and to allow the cover to be a little loose so the plants have room to grow. Shields constructed of tar paper, weed fabric or old carpeting may also be used. The shield will serve as an egg-laying barrier to adult flies. The shields are cut into 6 inch squares or 10 inch circles with a small hole in the center, and a slit is cut to the center. These are placed around the base of the transplant. Press them against the soil so that adult flies cannot crawl underneath. Scouting your plants is important, and hand picking the larva is usually productive. Additional sites to check out: http://rpalulis.hubpages.com/hub/Natural-Ways-To-Control-Cabbage-Worms http://homeguides.sfgate.com/put-garden-prevent-worms-radishes-26137.html http://www.toxicfreenc.org/organicgardening/cabbage_worms.html Hope this was helpful.