The home gardener is limited to diazinon as a soil insecticide, which is applied before or during planting. This may be justifiable when heavy infestations are common or seem certain. Diazinon sprays are applied to the ground and mixed into the top 2 to 3 inches of topsoil. Sprays can be placed in furrows or they may be directed at the soil around each stem. Diazinon acts primarily as a contact insecticide.
All controls are most effective when exercised with the nocturnal habits of the pest in mind.
The effectiveness and life of an insecticide is reduced as heat and sunlight increase. Therefore, it should not be applied in the morning. The quicker a spray or bait is contacted or eaten by a caterpillar, the more effective it is. Bees are spared when insecticides are applied in late afternoon or early evening. Cutworm moths are attracted to lights and pheromones, but these are only effective as a means of determining their presence and, to some extent, their numbers.