| If you have grubs in your lawn, the population needs to be high before you'll notice damage. How many grubs are too many? Research has shown that only 20 percent of home lawns and golf course fairways require treatment. Here?s a guide to treatment thresholds for European chafers, Japanese beetles, and Oriental beetles, the most common grubs in home lawns. Numbers are based on grubs/sq.ft. 0-5 grubs: rest easy Fewer than five grubs per square foot is a low population. You don?t need to treat. 6-9 grubs: think about your lawn Is your grass dense, with a healthy, robust root system? If so, it can probably withstand grub populations of 6-8 per square foot, or more. On the other hand, if animals such as skunks, raccoons, birds, and moles are digging up the turf to feed on the grubs and this bothers you, consider treating highly populated areas. 10 or more: they may cause damage Ten or more grubs per square foot will likely cause damage, especially if the lawn is otherwise stressed. In most circumstances, you?d be justified treating where populations are this high. Several weeks after treating, sample in a few locations to determine whether treatments were effective. You might be tempted to treat grubs in the spring, when you see last fall?s damage?but most spring treatments are a waste of time and money. The grubs have already damaged your lawn and are fairly resistant to insecticides at this time. Furthermore, even if you could eradicate them, summer will bring a new batch of beetles to your lawn. So, treat in the summer or fall to eradicate the pests. |
