Information on how the cabbage moth attacks gardens, and how to prevent destruction. Tips on the causes and cures of these pests.
So, you've labored long and hard over the winter months and now you've got yourself a vegetable garden. Time to sit back and enjoy the fruits (or rather the vegetables) of all of that hard work - right? Well, maybe. First though, you've got to make sure that you have control over the numerous garden pests who can, seemingly overnight, turn your bumper crop into a heap of useless compost. One of the most destructive early season pests is the cabbage maggot (Delia radicum). This pest not only affects its namesake the cabbage, but also can wreak havoc on the caulifower, broccoli, brussel sprout, radish, turnip, celery and beets.
The adult cabbage fly looks a lot like the common house fly but is a bit smaller, being about a quarter of an inch in length. The fly is a darkish ash gray and has black stripes on the thorax as well as black bristles over the body. The female will lay eggs which will hatch into white, legless maggots. These maggots feed on the roots of the vegetables already mentioned. The maggots will develop into brown egg shaped puparia which are to be found about one to five inches down into the soil. During the winter period the maggot lives in the soil. As Spring comes around and the soil warms up, the adult will emerge from the ground and begin to mate. Eggs will then be laid on the soil close to the host plant. After about a week the eggs will hatch and the tiny maggots will begin feeding on the roots of the host plant. They will, in fact, tunnel through the roots, in effect, destroying them. The effect of this will be that young cauliflower and cabbage plants will die. After three or four weeks the maggot will turn into a pupae and two to three weeks later the adult will come forth. The adult will now come to the surface of the ground to start the whole process over again.
In order to effectively control the ravages of the cabbage maggot, it is necessary to use pesticides. When working with pesticides it is important to carefully read the label on the container each time before you use it. Apply the pesticide only in the manner indicated and make sure that you dispose of any empty containers in a safe manner.
To control cabbage maggot damage to broccoli, Brussels Sprouts, Cabbage and Cauliflower use Diazanon 50 W at the dilution of one quarter to one half a pound per fifty gallons. Follow this up with Dyfonate 4EC at the dilution of 1 quart per 200 gallons of water. This should be directed to the base of the plant. You can also apply Lorsban 4E to the base of the plant.
To summarise, then, it is the maggot or larva stage of the cabbage fly that is the damaging stage to your garden vegetables. The maggots will attack the roots of the plant. The fly will go through three or four generations per year. The damage is primarily done in the period from May through to September. Control can be achieved with the careful use of Diazanon, Dyfonaten and Lorsban.
