Thе mоѕt common whіtе grubѕ іnfеѕtіng turf іn Cаnаdа аrе thоѕе оf thе nаtіvе June bееtlе оr Junе bug.
Most people know they feed on roots in spring, but they mature and lay eggs in summer months and that might be a good time to eliminate them. (see last paragraph)
Winter - White grubs overwinter as 3rd instar larvae. They do not feed during the winter. They move deep into the soil below the frost line.
Spring - White grubs make their way back up to the rootzone and continue feeding for a short period. They are fully grown at this point. It is common to see damage in the spring.
Summer - The white grub stops feeding and enters into the pupae stage where it transforms itself into an adult beetle. Adult beetles emerge during the summer months and lay eggs. The eggs hatch during late July early August and early 1st instar larvae begin feeding on the grass roots.
Fall - White grub larvae continue to grow and move into their 2nd and 3rd instar. feeding is aggressive into the late fall season. As winter approaches the larvae stop feeding and move deep into the soil to prepare for winter. It is common to see damage in the late summer early fall.
Visual Turf Damage Damage caused by white grubs can initially resemble drought stress which confuses many homeowners that don’t suspect grubs. As the grubs continue to feed and destroy the root system these areas begin to wilt and turn brown. Turf that has been severely damaged no longer has a root system and can be easily lifted away from the soil as there is no longer roots to anchor it. This makes it especially easy for animals to pull back, rip and tear sections of the lawn away.
Animal Damage Damage as a result of racoons, skunks and birds can often be the first sign to a homeowner that something isn’t right and white grubs may be present. Animal damage can be much more extensive than that caused by grubs. The animals dig away ripping turf back to get at grubs for a food source. Animal damage can be very frustrating as it is difficult to prevent from happening day after day.
What To Do
Lawn care The best thing you can do is to make sure your lawn is healthy before any problems happen. If you can, dig or till your land one year before you seed it or lay sod. Remove old plants and weeds, then rake/de-thatch your lawn or cultivate the soil thoroughly to expose any grubs to their predators and the weather.
Healthy, vigorously growing lawns can tolerate more grub feeding than stressed lawns, because damage to one root is made up for by others. Remove excessive thatch, and aerate compacted soil areas to ensure proper drainage. A soil aerator with spikes or spiked sandals can also help kill some of the grubs.
Beetles prefer to lay eggs in closely cropped lawns, so raise your summer mowing height to 6 to 8 cm (2.5 to 3 inches). Leave lawn clippings after mowing, because their slow release of nitrogen encourages micro-organisms to break down the thatch. Use fertilizer with high potassium and enough nitrogen.
If you notice grubs during the warm, dry periods of the growing season, water and fertilize your lawn to strengthen it and make up for the root feeding damage. Apply a top dressing of sand and manure and overseed with grass. Deep, infrequent watering encourages deep-rooted, drought-tolerant lawns. Water no more than once a week, and water until at least 2 cm (1 inch) of water collects in a container placed on your lawn or for about one hour.
Population control You can hand pick adult beetles or vacuum them using a small vacuum with a disposable bag. You can also shake beetles from plants and collect them in a cloth, placed directly below the plant. For best results, collect the beetles early in the morning when they are still sluggish. Put beetles in soapy water to kill them.