Here in Southern New Hampshire nematodes can be used to advantage for maybe another week or two.
Apparently the numbers of white grubs in Massachusetts — and surrounding states — this year is much higher than normal according to a pest update provided by the UMass Turf Program authored by Turf Entomologist Dr. Pat Vittum.
In the update Dr. Vittum explains what he thinks happened this year:
The dry weather of August forced some beetles to delay laying eggs because they could sense that the soil moisture was very low at that time and the eggs would not survive in the dry soil. So we saw lots of very small grubs in late August and early September, more so than usual. We did not see much damage at that point because many of the grubs were still pretty little.
Then as the “late” grubs matured and joined their brothers and sisters who had developed “on schedule”, the numbers of large grubs exceeded threshold levels pretty quickly. And meanwhile of course, most areas have not received much rain in September, so there has been little moisture available to mask the damage. — Dr. Pat Vittum
It make sense. Get the full story and decide for yourself. Do bear in mind, though, that while we value the insights, we do have to suggest you deal with the problem differently than what’s mentioned in the article. We know of two viable options that fit well into an Integrated Pest Management (IPM) program:
- Parasitic nematodes, Heterorhabditis bacteriophora.
- Milky spore disease, Bacillus popilliae.
So what’s this mean to you right now? It really depends on where you are and how cold it is. Here in Southern New Hampshire nematodes can be used to advantage for maybe another week or two — it has been warm so soil temps are still reasonable. If you’re having a bad problem with these pests it would probably be beneficial to act. Milky spore can be applied anytime before the ground is frozen. In either case, though, unless you have a significant problem, it’ll probably be more cost effective to wait until Mid April or so of 2008. But don’t forget! If you have some grubs now, April through June of next year (depending on the specific pest) will be worse. Come June they will be huge grubs with appetites to match.
Note: “White grubs” include pests like Japanese beetles, June beetles, chafers, and others. Use the links to learn more about these pernicious pests.
Have a regional pest making headlines? Tell us about it and make headlines here. We’re always seeking contributors who know pests and want to share.
David Zemens responds:
Posted: October 10th, 2007 at 7:46 am →
I have had a problem with grubs at my home in Michigan for many years now. I have been hesitant to apply many of the chemicals suggested to kill them because I have a dog, and live on a small city lot, and am concerned about the dog being in closed proximity to the chemicals.
Is there any potential for harm to my dog if I use the Milky Spore for grub control rather than the chemicals that have been suggested to me in the past?
Mike Cherim responds:
Posted: October 10th, 2007 at 10:20 am →
Hi David. Both milky spore and nematodes are safe to use around animals. Milky spore is a bacteria that’s pretty specific, whereas nematodes only go after the larvae of certain insects. Milky spores takes a bit — 2-3 years — to become fully effective as the bacteria colonies have spread throughout the turf area in which they were applied, but the residual control from this is 20-30 years easy unless your area suffers a massive drought. The nematodes are good to use in the interim period.
mark responds:
Posted: November 25th, 2007 at 3:45 pm →
Can you work on killing grubs on cape cod from Dec thru Feb? I was cleaning leaves and im finding out i have grubs in many many areas in my lawn, if any one can help with some information it would be very appreciative, thanks.
Mark
Mike Cherim responds:
Posted: November 25th, 2007 at 4:59 pm →
Hi Mark: Nematodes have the smallest working window, spring to early summer, and then late summer and fall. Milky spore powder can be applied anytime the ground isn’t frozen (though I wouldn’t recommend pushing that to either extreme end of the season), and that’s about it time-wise.
Thus, all I can suggest during the colder months is to keep turning up grubs as you have been. In doing so you are exposing them to predators like birds that will likely enjoy a grub snack during the colder months. Or, if you’re lacking bird activity, just hand collect them as you turn them up. That will be helpful at least, then treat more broadly once the weather warms.