Grubs, White

Don’t guess about grub damage and treatment! Sometimes damage from cold, drought, nematodes, or maintenance practices resembles grub damage. Use a knife or spade to cut several 1-foot square samples, 3 inches deep, from the edge of the damaged areas. Fold the sample back and examine the soil for grubs. Treatment is often required when an average of three to five grubs is found per square foot. Replace the sod carefully and pack it into place.  Beetles may re-infest the same areas year after year.  Water grass before treatment if the soil is dry unless prohibited by label. When dry soil conditions exist, watering before treatment causes grubs to move nearer the soil surface. Water thoroughly again after treatment is applied.  

Pesticides applied to lawns in July and early August will have the best control.  Do not confuse lawn applications with ornamental applications.  Spraying ornamentals will kill adult insects but the products used for this type of job usually do not have any noticeable effect on grubs.  Pesticide sprays can be used to kill adult beetles that are depositing eggs in your lawn.  This spraying does greatly reduce numbers of adults but is not necessarily a good substitute for proper lawn and soil treatment.
If pesticides are needed to control damage caused by adult beetles, use a long term product that is safe for desirable plants and that can also be used on lawns.  Talstar One (Talstar concentrate) is labeled for use on many different plants, shrubs, ornamentals around homes and in landscapes.  Use Talstar to spray plants that need protection from adult Japanese Beetles.

Lawn Applications to Control White Grubs

Conventional insecticides rarely give good control of these lawn pests.  Grubs are soil inhabitants that live and feed in areas where pesticides have trouble reaching.  For this reason it is best to use Merit insecticides for white grubs.  Merit Granular has two characteristics that help achieve control of such pests: super long residual and systemic action.  Merit Insecticides are available in granular formulation as well as wetable powder concentrate formulation: Merit .5G Insecticide Granules and Merit 75% Concentrate.

Season long control is a great advantage when fighting this lawn pest but the product can possibly break down under severe conditions such as water and extreme temperatures.  In most cases the summer/fall application of Merit systemic insecticide will do the trick.  If you live in an area where infestations are stubborn or difficult to control or if extremes in rainfall or temperatures might affect the insecticide, an extra application in late spring could be quite beneficial.

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