If you’re curious about those whitish, gray grub worms with brown faces writhing around in your grass, first of all, don’t worry. They are harmless to humans. These grub worms are the larvae of scarab beetles, and they are known as “white grubs.” White grubs are either white or gray, with a dark posterior abdomen and a brown head. Their longish wormlike bodies curl into C-shape.
Numerous species of white grubs currently exist all over the United States in most northern and Midwestern states, as well as in Florida. Just a few common White grubs include the Japanese beetle (Popillia japonica), May-June beetle (Phyllophaga fusca), false Japanese beetle (Strigoderma arbicola), northern masked chafer (Cyclocephala borealis), green June beetle (Cotinus nitida), European chafer (Rhizotrogus majalis), black turfgrass atanius (Ataenius spretulus), southern masked chafer (Cyclocephala lurida), and the Asiatic garden beetle (Maladera castanea).
White grubs feed on plants and the roots of turf grasses and the adult beetles feed on trees, shrubs, and other foliage. While white grubs are harmless to humans, they can be devastating to crops because they feed on crop roots. White grubs have three larval stages, with the third being the most devastating to crops. They hatch from eggs laid in soil and they also pupate in the soil. Fortunately, the adults are not considered turf pests.
It’s easy to tell whether you have a white grub infestation or not by the condition of the grass and the types of animals foraging around in your lawn or in your crops. When white grubs feed on grass roots, the grass turns yellow and dies. You will notice scattered brown patches of grass and the grass will pull up very easily. If you notice an increase in birds, moles, raccoons, and depending on what part of the country you live in, armadillos, this may be because you have a white grub infestation. If you notice wasps in large numbers hovering over your grass, this may also be a sign of a white grub infestation.
Before attempting to treat a white grub infestation, you can confirm that you have an infestation by digging up the top three to four inches of soil, roots, and thatch. Simply sift through the materials and look for the larvae. If you find them, then it’s time to explore treatment options.
White grubs have natural enemies such as ants, ground beetles, scoliids, and tiphiids. These natural predators may help to control the problem as well as keeping the soil dry, if at all possible. Preventative measures include insecticides such as Ortho Grub-B-Gon Max, Merit, Arena, Mach2, and Season-Long Grub Control.
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