[PROBLEMS & SOLUTIONS] Answers To Your Tough Pest Questions

FIELD MICE IN CRAWLSPACE

Q I have taken over an account that
has a mouse problem. Another pest management professional and the homeowner have treated the crawlspace. I am concerned about several things, including the use of baits in the crawl-space. The former pest management professional just threw bait blocks into the area. The homeowner has added d-Con®. There are some dead mice but they are all field mice. I have not found any evidence of dead house mice and have not seen any droppings from house mice. The crawlspace does have an open area where the mice can get into the living area (or at least the basement area where there is an exercise room and storage). The dead mice I have seen are nurturing other insects. What are your thoughts?

A Since we are dealing with field
mice you should change the bait. Although it appears to be working (you have seen dead mice and green droppings), seed baits are usually successful against these mice. Clean up all the baits blocks that are there now, including the d-Con. Since your company has a policy of using bait stations when placing baits, you have to decide where these may be placed. I would also suggest using glueboards in stations or along sill plates. These should be checked in a couple of weeks. Inspect the storage room area and place some stations with glueboards as monitors for both mice and insects.

Since the dead mice attract dermestids, flies and other scavengers, the homeowner may start to see flies in the part of the basement as mentioned above. The glueboard is an effective item to use not only because it traps mice but also because it controls those insects attracted to any dead mice on the glueboard. I have seen neglected glueboards that contain larvae and adult dermestid beetles, spider beetles and different flesh flies.

LOOK FOR THE BIRDSEED

Q Stored product pests, like the saw-
toothed grain beetle, a few weevils and Indian meal moths are showing up in good numbers in one of our accounts. I can’t seem to find the source. The customer keeps seeing moths and occasionally finding beetles. Any suggestions?

A I have found that one of the prime
sources for Indian meal moths is birdseed, which is also a source for sawtoothed grain beetles and weevils. Check to see if this is the case at the account. If not, then look for residual infestations and use pheromone traps to pinpoint areas where activity is still present.

NPCA-1 FORM QUESTIONS

Q I am having a problem interpreting
the NPCA-1 form. It states that we should note evidence of re-infesting wood boring beetles. When I look at an exit hole I seldom see the beetle itself. How do I know I am not looking at old evidence of a beetle like buprestid (which makes an oval hole similar to an old house borer [OHB]) or a shot hole borer (similar to an anobiid)?

A This is an interesting question and it is
one I feel many pest management professionals face during their inspections. Some non-reinfesting beetles have similar exit holes as re-infesting anobiids and possibly Cerambycid beetles. As for this example, buprestids do have an oval exit hole but it is usually larger then the OHB. Other Cerambycids, though, have similar- sized exit holes. Watch for some strange things if you are dealing with a log home. Beetles may re-infest when research says they do not.

The main thing is to try to determine the age of the damage. How old is the home? What conditions exist that could support an infestation? Are there any galleries that have been cut across? These can add up to no infestation. If you have fresh frass, I would say there is not a pest management professional out there that would not recommend treatment.

As for old evidence, i.e., dark exit holes, caked yellowing frass, etc., there are two ways to looks at this. First, if it is old and activity is gone (without identifying the specific insects), no treatment is needed. The next step is to wait. Wait until the season comes around for the emergence (there is a place on the NPCA-1 form for this specific recommendation). Spray paint the area or areas with a dark paint or place tape over the area (this may be difficult if the area has some moisture problems and depending on how long the tape has to be in place). Then come back during or after the emergence time for these beetles (late May-early July) and see if there are new holes. If so, treatment is needed. If not, walk away.

The author is president of George Rambo Consulting Services, Central, S.C. Fax questions to him at 864/654-2447 or via e-mail at grambo@pctonline.com.