Grubs, the larvae of scarab beetles, can harm grass and lawns by feeding on stems and leaves. Signs of a grub infestation include dry, patchy grass, animals digging in the grass, and telltale indications like patches of dead or dying grass and spongy turf. Controlling and eradicating grubs requires different methods such as bacteria or insecticides based on their life cycle stage. It is an essential part of lawn maintenance as these pests are prevalent across the U.S., especially in areas with rainy seasons and moist soils. To effectively deal with grubs, it is crucial to understand how to identify an infestation, the appropriate treatment methods, and when to take action for optimal results.
Lawn grubs, which are the larvae of scarab beetles, are attracted to different turf grasses and climates, with Japanese and June beetle grubs being the most common. They feed on grass roots and stems, while adult beetles damage leaves on ornamentals and crops. Signs of a grub infestation include irregular patches of dead grass, spongy turf, easily peeled back grass patches, dry-looking lawns even after watering, small holes from animal digging, tunneling and mounding caused by moles, large bird populations on your lawn, and swarms of beetles near the ground. Checking for grubs in early autumn by digging up turf can help determine if there is a problem, with more than five Japanese or June beetle grubs indicating an issue.
Effective grub control relies on timing and the growth phase of the insect, with treatment options being either preventive or curative depending on the circumstances. Preventive insecticides like imidacloprid, thiamethoxam, or clothianidin can target and destroy newly laid eggs, reducing numbers for the following spring. Curative insecticides such as Carbaryl and Trichlorfon can be applied when grubs actively feed from early autumn until late spring to reduce the current season’s grub population. It is crucial to mow before applying insecticides to protect pollinators, distribute granular products evenly, and water them in properly. Regular maintenance of the lawn with adequate water and fertilizer is also important to manage grub infestations effectively.
During the following summer, apply insecticide for ongoing control. If you notice a significant number of grubs per square foot of sod or observe swarming adults, multiple applications may be necessary to bring the populations under control. In such cases, it may be more efficient and cost-effective to seek help from a professional lawn care service, especially in areas where a license is required to dispense specific insecticides.
Milky spore is a bacterial disease that offers long-term control for Japanese beetles. To effectively spread, the active organism requires ten or more grubs per square foot and may take two to four years to achieve complete control in an infected lawn. Apply milky spore powder in a grid pattern, using a teaspoon every 4 feet in rows spaced 4 feet apart. This method is most effective when larvae are immature and won’t harm other insects, remaining in the soil for up to fifteen years.
Beneficial nematodes are parasites that target grubs by entering their body openings and multiplying rapidly. They are available in various forms like sponges, gels, granules, or liquid and work best when applied to moist soil in the morning, evening, or on an overcast day. These nematodes should be stored in the refrigerator and applied after watering the dry ground to a depth of half an inch. While they act quickly, prolonged dry periods may necessitate a second application.
Neem oil is a botanical pesticide that disrupts feeding, growth, and egg laying in insects. It is most effective when applied from late summer to early autumn. Follow the product label instructions for mixing and spray the affected areas accordingly.
Diatomaceous earth is an organic solution that kills all soft-bodied insects, including butterfly and lady beetle larvae, by dehydrating and causing death. It is made of silica and is best used for spot treatment in powder form, following the label directions for application.
Commonly Asked Questions:
– Can dish soap kill grubs? While dish soap suffocates pests, a more targeted option is insecticidal soap, designed to avoid harming plants and beneficial insects.
– How can I bring grubs to the surface? Drench the affected areas with water or a soap and water solution to induce grubs to surface and avoid irritation and suffocation.
