You Are Here: Management Updates 2009 Archive June 26, 2009

Date: June 26, 2009
Category: Insects
Subject: White Grubs, Webworms, Black Cutworms

Now that most of the golf course superintendents in southern New England have gotten through the worst of the first generation of annual bluegrass weevils, I thought I would take this opportunity to comment on other insect activity.

Oriental beetles have been flying in the Amherst area for about a week now, although there are still some larvae and pupae in the ground. Japanese beetle adults should start flying within the next week. European chafer adults have been flying in many southern New England locations for over a week, and should start showing up soon in southern New Hampshire if they haven't already done so. Reports from the UMass Extension Landscape, Nursery, Urban Forestry group indicate that Asiatic garden beetles have been flying for a week or two as well.

For those of you who are planning to use a neonicotinoid to control white grub populations, and have not yet applied those materials, note that most labels of neonicotinoids recommend treating when adults are laying eggs. That period should begin very soon in most of New England (and remember that European chafers will start laying eggs a little earlier than oriental beetles and Japanese beetles).

The neonicotinoids include: chlothianidin (Arena™), imidacloprid (Merit™ and other trade names now), and thiamethoxam (Meridian™). In addition neonicotinoids are available in some combination products. Allectus™ contains Merit™ and Talstar™ while Aloft™ contains Arena™ and a generic form of bifenthrin. These two products have been available for commercial turf managers for at least a couple years. According to Dave Shetlar (my counterpart at Ohio State), there is a new homeowner combination product on the market, Maxide Grub Killer™, which contains Meridian™ and Scimitar™. All of these materials, whether used as a neonicotinoid alone or in a combination with a pyrethroid, should be applied while adults are laying eggs. While it is too early to know what our summer weather will be, you certainly should aim to have those applications finished by early August.

The pyrethroid part of a combination product should also provide good protection against chinchbugs as they become active.

Another preventive product for white grubs is chlorantraniliprole (Acelepryn™). While the recommendations generally suggest that Acelepryn should be applied by early June for control of subsequent white grub populations, several of my colleagues and I have field data that indicate early summer applications can also be effective. But don't delay much longer if you are going to use Acelepryn™. (Note that Acelepryn™ is not yet registered in New York, but is available in all other states - except perhaps Hawaii).

We have noticed a few webworms flitting about just above the surface of the turf on the few occasions when it has not been raining. Now that the temperatures appear to be warming up and we may finally catch a respite from the steady rain of the last two weeks, be on the look-out for webworms in lawn and landscape settings. Webworms seldom cause enough damage to warrant treatment in New England, but I received some pretty convincing photos from some turf managers last year, so take a look now - and watch for small caterpillars in the turf about 10 to 14 days from now.

I have had several reports from golf course superintendents indicating that black cutworm activity is on the upswing. You might want to consider taking action now that soils are beginning to dry out. Pyrethroids are always an excellent option (unless you have a pyrethroid-resistant population of annual bluegrass weevils). Also the new product, indoxacarb (Provaunt™) appears to be extremely effective against caterpillars. (The same products should also be very effective against webworms).

Submitted by: Dr. Pat Vittum

DISCLAIMER - As always, it is the responsibility of the applicator to verify the registration status of any pesticide BEFORE applying it. Different states have different regulations as well. The author and the University of Massachusetts are not liable for any consequences of any pesticide "recommendations". Mention of any trade name is not to be considered endorsement of a product.

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