When Is the Best Time to Treat for Grubs & Moles in the Yard?

When to Treat for Grubs

• Grubs are the larvae of Japanese beetles, June beetles and chafers. So the presence of these coupled with dead patches throughout your yard can signal a grub problem, and if they go unchecked they can destroy your lawn. The presence of six or more grubs underneath a square foot of turf means it is time for action. The best time to apply grub treatment is when the grubs are small, either right after they have hatched or just before they hatch. When you see adult Japanese beetles flying around in June or July, apply treatment. However, some curative insecticides should be applied in September or October.

What to Use to Treat for Grubs

• Treating for grubs begins by treating for beetles and chafers. Beetles prefer dead, depleted soil that results from overuse of chemical fertilizers. Introducing milky spore disease or beneficial nematodes helps to control beetles. One of the best ways to control grubs directly is to drench the soil with beneficial nematodes. The best way to prevent grubs besides keeping your lawn free of beetles is to keep your lawn healthy. Avoid using fertilizers high in nitrogen to keep from depleting the soil of nutrients and killing beneficial bacteria. Both preventive and curative insecticides are available to use on grubs. Preventive insecticides include imidacloprid, thiamethoxam and chlorantraniloprole. Curative ones include carbaryl and trichlorfon.

When to Treat for Moles

• Moles feed on grubs, which means that moles may be indicative of a grub problem. They also eat other crane fly larvae, slugs and other garden pests. They spend almost their entire lives underground and possess a number of features that help them navigate the underground world -- a sensitive sense of touch and the ability to detect airflow, prey and even metallic objects. To deal with the grubs that are possibly attracting the moles, treatment is best applied in June or July when grubs are closer to the surface. However, if using a mole trap, spring and fall are the preferred times for action.

What to Use to Get Rid of Moles

• If getting rid of the grubs doesn’t get rid of all the moles, you do have other options. Castor oil-based repellent has shown to be successful in repelling moles in the eastern United States. The repellent works by coating earthworms and other prey that leave a bad taste in the mole’s mouth. Castor oil-based repellents are available commercially. Although toxicants and fumigants are available for use on moles, traps are reported to work the best. A few types of traps are available, but they do not usually allow for live capture. Capturing moles alive for relocation can be done in a couple of ways. One way involves going out in the early morning hours or in the evening when the mole is heaving the earth, quietly sneaking up on it and inserting a spade into the ground behind it and quickly throwing it out onto the surface of the ground. Just make sure you have a box ready for its capture. Another way to capture a mole alive is by placing a wide-mouthed quart jar in the ground beneath the mole's tunnel and placing a board across the entrance of the burrow. When the mole comes down the path, it falls into the jar. The jar can then be removed, and the mole can be relocated and released.