Information on repelling Japanese beetles and their grubs
Japanese Beetles are the bane of the rose gardener, but they also feed on about 300 other species of plants. Most gardeners loathe the sight of their return each summer around mid- to late June and hope for the best as they begin their month-long feeding and mating frenzy that defoliates our prized plants.Beetles can travel up to a 5-mile radius but generally stick to a 1- to 2-mile area if the food source and egg-laying conditions are favorable. A single Japanese Beetle doesn’t do a lot of damage but they generally feed in larger groups, working from the top of a plant downward and preferring plants that are in full sun.
The life cycle of the Japanese Beetle begins again as soon as the adults emerge and begin to mate. Females will burrow into the ground in the afternoon and lay 1 to 4 eggs every 3 to 4 days. The eggs will hatch to a larva—or the familiar white grub—state where they continue to develop for 10 months. The grubs prefer moist soil with lots of organic matter, and they especially love tender grasses. They are drought tolerant and will move deeper into the soil if late summer rains aren’t forthcoming. It is during this feeding period they can do the most damage to your lawn grasses.
They over-winter in this grub stage, moving deeper into the soil to withstand any cold weather and become inactive when soil temperature drop below 50 degrees. Many birds such as starlings, common grackles and crows will eat grubs in heavily infested areas. A sure sign of infestation is a large flock of starlings digging up the grubs with their long, pointed bills or crows pulling up small pieces of turf as they dig and search. Moles, shrews and skunks will also feed on the grubs.
A natural method of grub control is milky spore. We sell the spores of the bacterium in two different application types, powder or granular. The spores will reduce the number of Japanese beetle grubs in your lawn but will not stop the flight of adult beetles. Our Milky Spore product is available in several sizes AND we carry a very handy applicator for use with the powder. It makes application effortless and your back will appreciate not having to do all the bending!
The best natural way to detour adult beetles from your property is Nocdown cedar oil-based insect repellent. Its odor is noxious to beetles and other pests, and it is an all-natural way to repel them, or if they stick around, it will shut down their receptors, and they’ll eventually leave or starve and die. We carry three economical sizes of Nocdown
An easy, natural method of control for the adult Japanese beetle is hand collecting. This is best done early in the morning when the beetles are not as active. Reducing the numbers on a plant makes it less attractive to other beetles flying in. Shake or knock them into a bucket of soapy water to kill them.
We don’t recommend the use of Japanese beetle traps for home landscapes. They should be limited to large open areas away from valuable plants because the powerful attractant can actually draw more beetles into an area. We also don’t recommend toxic insecticidal sprays and dusts to protect ornamental plantings as they can contaminate food crops.
One more effective means of controlling grubs and adult Japanese beetles is Food Grade Diatomaceous Earth. It works by a physical, non-chemical process of destroying the exoskeleton of pests. It’s like tiny shards of broken glass that will kill them as they come in contact. Since it’s non-toxic, it is safe if ingested by warm-blooded creatures. It can be sprinkled liberally on plants and on the soil. However, it’s best to use a garden duster, taking care not to inhale the dust. We carry both 5-pound and 50-pound bags.
Japanese beetle infestation can be frustrating, but it’s easy to fight the destructive pests the natural way, with our easy-to-use and safe products: Milky Spore, Nocdown and Diatomaceous Earth.
July 24th, 2008 at 4:19 am
How can I tell if the grubs in my yard are Japanese beetle or some other type of beetle?
July 26th, 2008 at 10:23 am
Grubs are the larval stage for many types of beetles in the scarab family–not only the Japanese Beetle but May and June Beetles, Asiatic garden beetles and brown chafers. The most obvious identifier for the grubs versus other larvae that live in your yard is their whitish coloring and C-shaped bodies; after that you have to get pretty up-close and personal to the grub to distinguish between the different species by sight. So to know if you are treating just the Japanese Beetle larvae, you have to really know the life cycle.
Japanese Beetles will emerge from the larva stage in early June, eat your lovely flowers and shrubs and mate until late July. Their adult life span is only about six weeks long, during which time the female will continually lay eggs. These eggs will hatch around August into the larva or grub stage and it is then they do the most damage to your lawn. They are eating voraciously to develop enough food storage to over-winter deeper below the surface of the soil. This is also the time when your lawn can be most stressed from the heat and drought of summer. The appearance of large brown spots, a large number of birds feeding on the lawn, or moles burrowing in your yard could be a good indicator of their presence. By September the grubs will be finishing feeding and will move deeper into the soil for the winter months and not appear again until about mid-April. Therefore any chemical treatment is only effective during the times that the grub is feeding, and is best applied in the fall feeding cycle; treating any other time is a waste. A non-chemical means of control includes the use of a bacterial disease called Milky Spore and it infects the blood of the grubs. This process is slower, but it is not harmful to people, other insects or animals.
September 21st, 2009 at 11:03 am
i have grub problems when is it best months to apply grub application and what to apply and what month please.
September 22nd, 2009 at 8:14 am
You can apply Milky Spore any time except when the ground is frozen. It will start working as soon as it has been applied.