White Grubs

White grubs are the larvae of scarab beetles. The grubs of economic importance in North Carolina are those of the Japanese beetle, the green June beetle, the southern masked chafer, the northern masked chafer, and the Asiatic garden beetle. Several other species, such as May beetles and June beetles, are also present but usually in low numbers. The Japanese beetle is consistently the most damaging grub in this state. All these grubs have cream colored bodies with yellow to brownish heads, brownish hind parts, and six legs. Mature grubs vary in length from 1/4 to 1-1/2 inches, depending on the species. White grubs usually lie in a curled or C-shaped position.

White grubs can be controlled in a timely and economical manner if proper controls are correctly applied at the right time. To prevent serious damage, examine all turf in early September for the presence of grubs. Do not wait for brown patches to appear in the turf before inspecting the soil. Birds, moles and raccoons all feed to some extent on grubs, and their digging in the lawn may be a sign of a white grub infestation. However, it is best to verify that grubs are actually present before applying pesticides. Use a heavy-duty knife or a spade to cut a 1-square-foot flap of sod and roll it back. Examine the soil and roots in the top 3 or 4 inches. Repeat this process in several locations. If you find an average of five or more grubs per square foot, a pesticide application is justified.

Since grubs are small and near the surface in the fall it is a great time to treat for their control. A biological treatment method, useful against only Japanese beetle grubs, is the application of milky spore bacteria. This commercially available bacteria, when applied to the soil, infects the grubs and produces a disease. Grubs in the soil come in contact with the spores through ingestion. The spores germinate inside the grubs, eventually killing them. These spores work best when applied in late September or early October to soil with a pH level between 6 and 7. The results are not as rapid as with chemical insecticides, but the effects last many years. When milky spore disease becomes established, it will spread naturally to adjoining, untreated areas. Application at the time of turf installation may result in a more uniform distribution of the spores in the soil. This product is available at many garden shops under such trade names as Doom®, Japidemic®, or Milky Spore.

During this time of year, the easiest product for home gardeners to apply for quick grub control is diazinon granular formulations. Diazinon granular products can be applied with a rotary spreader like you spread fertilizer in and should be watered in after application by irrigation or rainfall. Best control of grubs will be with an application during the month of September.

Tall Fescue

Although tall fescue does not perform well in our area, it can survive under certain conditions. Tall fescue is best suited to clay soils in shaded areas with efficient irrigation systems.

The best chance or success with tall fescue from seed is to plant between September 15 and October 15. By seeding in the fall, fescue has the best chance of surviving summer since it has time over the fall, winter and spring to develop a strong root system. In existing lawns run a dethatcher or core aerator over the area before overseeding to disturb the soil and get good seed to soil contact. After seeding drag something over the lawn to get the seed in contact with soil and water in.

If you plan on seeding a new lawn, soil test, apply recommended nutrients, till the area, rake, seed, rake or roll to get seed to soil contact, mulch with wheat straw, and water in. Keep the top one half inch of soil moist until the seed germinates and then cut back irrigation to apply 1 inch per week in absence of rainfall.

Overseeding

In warm season grasses like bermudagrass overseeding with annual or perennial ryegrass can be done to have a green lawn year around. Use a core aerator two weeks before overseeding to disturb the soil. After seeding at a rate of about 5 pounds per 1000 square feet rake or drag the area and water in to get good seed to soil contact. Water in absence of rainfall to keep top one half inch of soil moist until ryegrass has germinated. Once winter arrives we usually get enough rainfall to sustain ryegrasses without supplemental irrigation.

Prevent Weeds Now

September is a great time make herbicide applications to prevent winter lawn weeds that are always a problem come next spring. Annual bluegrass is the major grass type weed we have in dormant warm season lawns. Annual bluegrass can be prevented by using preemergence applied herbicides that contain Balan or Team. These are granular products that can be applied with a spreader according to label and watered in after application by irrigation or rainfall. The herbicide application forms a barrier that kills annual bluegrass just as it begins to germinate. Most products labeled for preventing crabgrass contain one of these products and can be used to prevent annual bluegrass.