Some people have said to me that the grubs in their lawn came from their neighbor’s lawn. That is not true. Others are worried that just a few in their lawn will multiply and kill the whole lawn. That also is not true. Then there are companies who are eager to sell you grub treatments in the spring. This is a waste of money. Some people wait till the fall to address the problem. And that could be a big mistake. So let’s look at the facts. Because if you know your enemy, you can win the battle against them.
Annual white grubs are the larva stage of a beetle; either a Japanese beetle or June beetle. These beetles mate and lay their eggs from late June to mid July; eggs hatching in 10 to 14 days. The grubs feed on the grass roots from midsummer to mid-fall at which time they burrow down deep into the soil for the winter. In the spring they return to the root zone when the soil gets to 50°. At that time they do not eat as much as in the fall. They pupate in the soil and emerge as adult beetles weeks later.
Since the beetles prefer to lay their eggs in warm and moist soil, sunny, well-watered lawns are the most susceptible to infestation. Therefore, if all your neighbors water regularly or there are frequent rains during late June early July, the beetles will be laying eggs in all sunny turf areas and the concentrations will be less, and less likely to be enough to cause noticeable damage. Usually it takes 10 or more grubs per sq. ft. to eat enough root material to be a danger.
TML offers a preventative treatment that is applied in late June. This is when the grubs first hatch and are most vulnerable. If however, you discover an infestation in the fall, because grubs have started to damage your lawn, a much heavier dose of insecticide (12x more!!) is needed to deal with these much larger grubs. That’s when we recommend this emergency curative application and recovery measures. So, if you want to minimize the risk of grub damage and the use of the much heavier dose of insecticide, the June application is the answer.