Soil insecticides are a common traditional method of controlling insect pests. Basically, there are two ways in which a soil insecticide can be considered effective:

• Repellency. The insects actively avoid the area containing the insecticide.
• Lethality or toxicity. The insects are killed by the insecticide in the soil.

Either of these actions is useful in termite control. Our research has explored the efficacy of various insecticides, many of which are commercially available.

There is also a new breed of insecticides that is gaining recognition and acceptance. These new compounds combine the characteristics of low repellency and delayed toxicity. The theory behind this approach is that larger portions of a termite colony's population can come in contact with the pesticide due to its low repellency. And since mortality is delayed, the termites do not associate negatively with the treated area, assuring continual exposure. Delayed toxicity also aids in any possible carry-back effect, where exposed individuals unknowingly transfer pesticide to other colony members outside of the treated area.

Soil insecticide longevity project The Termite Project has been engaged in a long-term, ongoing soil termiticide study for over 25 years. The information gathered by this study has a broad range of applications, especially for pest control operators and homeowners. This article summarizes some of our results from the early 1990s.