In my own case, I converted my vegetable garden into a lawn area when we acquired a summer home. However, I can see a time when, with children grown and married, we may give up summer jaunts and resume vegetable gardening. If you, too, foresee the possibility that food crops may someday be grown on present lawn areas, the use of large doses of D.D.T. for grub-proofing and so forth would seem unwise. On lawn areas which are not so likely to be plowed up and converted, this chemical (which costs much less than chlordane) is the preferred treatment for many soil insects.
Except where cost is a factor, as when a large lawn must be treated, chlordane is the most satisfactory soil pest control for amateur use.
Benzine hexachloride, called BHC for short, is widely used on farm crops. It has no place in the home garden. Less than a pound to 1,000 square feet will seriously injure many plants. It contaminates all root crops so strongly that they cannot be eaten.
Many insects spend all or part of their life cycle underground but do not properly come within the scope of this chapter. For example the tomato hornworm, a thick, ugly green insect familiar to anyone who grows tomatoes, does go underground to pupate but since it does not feed there, and cannot be controlled by soil treatment, it is not included in my discussion of soil-inhabiting insects. Proper to this chapter is the May beetle or June bug; it spends three years underground, feeding and injuring plants, during which period it can be controlled with soil insecticides.
The best way to attack insects that spend part of their life cycles underground and cannot be reached by chemicals is to dig or plow all areas not in use as soon as possible in fall, leaving clods and lumps rather than raking the areas to a level surface. If you delay this job until killing frosts have occurred, it will not be too effective. Most insects have laid their eggs by mid-September in the North. I find that control is much more complete if the soil is turned twice, or, better, three times before the first crusting by frost occurs. This exposes insect pests, as well as weed seeds, to migrating fall birds, many of which leave the North before frost comes. Fall rains wash out buried eggs, exposing them to frost action and to birds that remain over winter.