The Japanese beetle will not only eat foliage, the grubs will eat your lawn!
There are about eight major types of grubs in NH and VT that cause turf damage, ranging from the classic Japanese beetle to a masked chafer. Grubs will cause lawn damage plus the adults will devour ornamental shrubs and trees in your landscape. The potential loss of your investment makes controlling the young and adult stage of these beetles a sensible decision. Luckily, there are organic and new products available to help control these villains plus many others!
As always, the best defense is a good offense. Healthy turf can withstand root pruning and even minor damage without a pesticide being applied – even an organic one. Proper cultural practices, such as proper irrigation and a high 3” mowing height, also help keep your lawn cooler and less desirable to adult beetles. Overseeding with resistant turf varieties makes the grass taste less desirable, not necessarily to grubs but to their buddies above ground like chinch bugs, sod webworm and such.
New and old research shows that compost tea actually helps grass develop its own immune response to reduce damage from both insect and disease activity. Although not an easy turf treatment, beneficial nematodes provide 100% organic control in the spring or fall. Milky spore disease was developed a long time ago to control only Japanese beetle grubs, not the other seven. Unfortunately, the spores take years to develop due to the cold New England winters. As a result, Milky spore is not recommended by professionals as it simply does not work in NH or VT.
New organic pesticides that are ORMI certified contain capcaisin, the active ingredient in hot peppers. To obtain good results, and because the organic treatments are short-lived, multiple visits are required in the spring and fall to obtain predictable results. Even organic pesticides require extensive licensing and certification in both NH and VT. If you are considering “professional help,” be sure to ask for the company’s NHPC number in NH or license certification in VT before having any treatment done on your property- organic or otherwise! The potential damage inflicted by an application remains substantial, even if the material used is 100% organic, with improper rates, training, and equipment. In today’s economy, everyone with a pickup truck claims he is an organic landscaper but doesn’t have the credentials, insurance, or education to back up the temporary lettering.
For those ‘do-it-yourself’ folks, be careful what you purchase and use this spring. For instance, “Grubex” is another name for Acelypryn, a great new product for controlling grubs and other harmful insects. Unfortunately, if used at the wrong time, your application will not work due to the size and life stage of the pest you may desire to eliminate. This factor underscores the importance of proper training and state certification where turf technicians must learn not only insect but local disease pests.
While the bag you buy at your hardware store may be well labeled for grubs, you may not be applying it at the right time or stage of the pest. Said another way, just because the bag says it controls pests X, Y, and Z does not mean you are going to control them due to the time of year. This type of activity would be the definition of a waste of money, time, and chemical. Without the proper information on the life cycle of the pest you seek to destroy or reduce, applying home products is like shooting in the dark.
In summary, there are lots of ways to help your lawn look great, with the best and least environmental impact being the cultural and day to day upkeep of the turf. Integrating resistant grasses during lawn overseeding/establishment and implementing organic or natural bacterial and friendly fungi are super tools with no harmful side effects. In my opinion, pesticides should only be used as a last resort or when there may be a history of continual damage on a scale that would outweigh the omission of such products. In other words, a $400 treatment outweighs a $5,000 renovation!