The Witchetty Grub is a staple of Australian Aboriginal diets, but in the United States the grub is a highly destructive pest that can be difficult to kill. Emerging prominently in late July to early August, the white grub is a phase of the Japanese Beetle life cycle. Adult beetles feed on foliage and fruit while grubs inhabit soil and eat roots. Grubs have few natural predators (though moles do eat grubs) and financial losses attributed to the larval stage have been estimated by the USDA at over $200 million per year. Even the most Earth-friendly landscapers spray chemicals to kill these grubs when they find dried, gray-ash turf.
Grubs are best controlled with insecticides between late June and mid-July, when they are close to the surface and feeding. Diazinon was a popular pesticide before it was outlawed by the government and its products for residential use were taken off the market in 2005. Products containing carbaryl (brand name Sevin) are effective, as are those in the Bayer line. Grubs found in the spring do not need to be targeted, but if sighted in September and October, it is better to use products that work in 24 hours. If you applied insecticides prior to June, the Internet Center for Wildlife Damage Management recommends keeping close watch on your lawn again in August.
A Love Bug Solution
Organic grub preventatives like All Natural Lawn Grub Control must be applied more than once since they are purposefully not long-lasting in the environment while other control methods like milky spore disease, introduced by products like St. Gabriel Organics Grub Control, may take years to be effective in cool climates. In The Garden Primer, Barbara Damrosch tells us that some warning signs of grubs include plants wilting, and you should avoid planting where sod has been growing. If you need help ridding your lawn or garden of grubs, your local Cooperative Extension can be a good resource.