Grub Control And Prevention: How To Identify And Treat White Grubs

Between worrying about fertilizing, over seeding, mowing and watering lawns, sometimes homeowners overlook proper grub control and prevention. This aspect of your lawn maintenance routine is extremely important and should receive close attention because grubs have the potential to destroy the health of your grass rapidly.

White grubs (i.e., larval stages of Japanese beetles and masked chafers) in particular present a significant hazard to homeowners working to maintain a healthy lawn. Feeding below the soil, white grubs consume roots and rhizomes of all species of grass and may eventually destroy an entire root system. Infestations invariably go unnoticed before late summer, when it is too late to prevent significant losses of the lawn.

Grub control and prevention is part of a comprehensive year-round lawn care program. Your lawn care professional should identify, prevent and treat grub infestations as needed. Learn more about how to incorporate grub control and prevention into your lawn maintenance routine.

Identifying A White Grub Problem

White grubs overwinter in soil and transition to adulthood in late spring and early summer. Female adults actively deposit large numbers of eggs just below the soil surface, which hatch to produce white grubs (larvae) in summer.  It is these larvae or grubs that damage plants by feeding on roots and are identifiable as creamy white with three pairs of legs. Usually, white grubs curve their bodies into a C-shape, and larger species reach lengths up to 1 to 1 ½ inches.

A variety of wild animals enjoy eating turf insects. If you see the following animals foraging in certain areas of your lawn, especially if that turf shows signs of discoloration and/or browning from drought stress, it’s a strong indication that you may have a white grub infestation:

  • Raccoons
  • Skunks
  • Moles
  • Flocks of birds

Your lawn care professional should be making observations in mid-to-late summer for early signs of grub damage by inspecting the root zone for signs and symptoms of grub activity. Once white grub damage becomes evident, they already will have destroyed a significant portion of your root structure. To scout for grub activity n discolored or wilting areas of the lawn, cut two 6-inch by 6-inch sections of turf on three sides, peel back the grass layer and analyze the top two inches of roots for white grubs.

Preventative Measures And White Grub Treatment

Preventing a white grub infestation before it becomes a problem is the only truly cost effective approach to managing grubs. Products containing the following compounds work to prevent white grubs, but to be effective, they must be applied before egg laying in June or early July.

  • Imidacloprid
  • Thiamethoxam
  • Clothianidin
  • Chlorantraniloprole

These products do not work well in late summer after large grubs have been actively feeding in August and September.  Spring treatments of the aforementioned are also ineffective.  Only trichlorfon is highly effective for curative control or suppression of white grubs, but it must be thoroughly watered-in and even then significant damage remains likely.  Cararyl also is available for curative grub control; however, it does not effectively penetrate surface organic matter and usually provides poor control.

To ensure a healthy lawn, your lawn maintenance routine should include effective preventive grub control measures. Timing is extremely important and preventive control measures are best applied in June to ensure a green and healthy lawn by summers’ end.

Speaking with a lawn care professional is helpful when you have questions about how to recognize white grub activity in your turf or the best way to prevent and treat this damaging lawn problem. It is also beneficial to  educate yourself  on methods for maintaining a beautiful lawn year-round.

Ready to learn more about how to ensure a healthy lawn all year? Discover expert techniques of an effective lawn care program for every season.

»  For photographs of insect pests and their effects on lawns see Lawns

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