QUESTION:

Wasps in a drop ceiling are coming down into an office. Are there traps available, or what would be the best approach?

ANSWER:

I normally would say that whether or not there are traps available would depend on the kind of wasp you are dealing with, but since this is indoors it is unlikely that any of the pest wasps would be interested in a trap. The only exception could be UV light traps that could draw these wasps to the light, particularly at night, to capture them on the glue pads. For outside use there are yellow jacket traps that are relatively effective for some species of the pest yellowjackets, but no really effective traps for the other paper wasps we call Umbrella Wasps. These ladies stick to natural foods, and are not interested in artificial lures or baits that we have in traps for yellowjackets.

From my experience, and this early in the year, you probably have umbrella wasps in the genus Polistes. These make smaller colonies than yellowjackets (YJ's) and generally leave the bottom of their nest open and exposed. Very often the overwintering queens will become active in the spring and begin looking for a way out of wherever they spent the winter, and often move down into living and working areas from attics and other spaces overhead. YJ's also end up in living areas, but this often happens later in the summer when their nest-building has created such a massive nest that they need more room, and they chew through sheetrock or ceiling panels to move downward.

At this point I suggest putting on the proper protective clothing (hood, gloves, hat, thick clothing) and taking a really good look in the attic space above this drop ceiling. You may be able to locate the nests themselves if this is an active colony, and if so you can treat it directly with one of the directed "freeze" type wasp aerosols. If you cannot locate a nest, or if it is just overwintering females, you might try placing a UV trap up in that space for a week to see if you can draw the wasps to it. It also would be prudent to make a careful inspection of the outside of this building to see where the wasps may be finding access to the attic space, and if at all possible close off that opportunity with better screening or some other exclusion material to prevent future problems.

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