[Problems & Solutions] Answers To Your Tough Questions

December 11, 2003


Q I have seen an amazing number of spiders this year. Can it be related to the weather? Or are we missing something important in our control programs around structures?

A I agree this year has been a banner year for spiders. In some ways it may be related to the weather. Last year (a relatively dry summer in the East) we had spiders but not in the numbers I have seen this year. The wet weather in the East has been a problem in a lot of ways — even the snowfall of winter has aided insect populations. Snow insulates them and many overwintering arthropods emerge from winter just fine.

The lush plant growth means more plant feeders — generally the prey of spiders. The populations of flying insects are also an indication of what the spiders have available to catch. In short there appears to be high populations of most everything except termite swarms this year.

Your control program should emphasize a crack and crevice treatment along the exterior of the structure. Pay attention to the eaves and any lights that may be used around the structure. Sweep down webs and encourage homeowners to make sure doors and windows do not have gaps that spiders or other small arthropods can use to gain access to the structure. You may forget that light from windows and doors attracts night-flying insects. Web-building spiders will build their webs where insects are active.

There are products that can discourage web building. Check with your distributors about these products, but make sure sprayed surfaces will not stain. These products have been effectively used by many pest management professionals.


Q I have found hundreds of fast-moving larvae on the walkways outside one of my accounts. What are they and what can I do about them?

A The larvae may indeed look strange because pest management professionals do not come across this insect very often. The larvae that this reader encountered and sent in to me is that of a soldier fly. These flies lay their eggs in decaying vegetation — or worse. The adult itself is rather large, has long legs and is a strong flyer.

These larvae are moving (as most do) away from their feeding area to pupate. They usually breed around moist areas. Try to find the source of the pest, maybe a wet area nearby.

This is definitely a rare pest for our industry. In all of my years of pest management experience, I only have had one of these pests show up inside a structure.


Q. Some of my customers’ homes have had problems with Indian meal moths. I have placed pheromone traps inside the house and have found that most are trapped around the fireplace. What is the reason for this?

A. Either type of fireplace — masonry or insert — can present an interesting problem with Indian meal moths. My guess would be that squirrels are contributing to this problem. Perhaps they have found a deposit for the nuts they have been harvesting and unfortunately for the homeowners, this area is a void either in or around their fireplace. I have heard several reports of this situation this year.

What can be done to solve the problem? Continued trapping with pheromones will help. If they can be found, dusting into the voids could reduce the number of Indian meal moths. If you’re dealing with an insert-type fireplace, try going into the attic and looking for signs of the moths there too. Place a trap or two in the attic and continue to monitor. You may be able to dust into voids around the fireplace from the attic.

If the fireplace is made of masonry you likely will have a problem. Squirrels have been known to harvest nuts and place them behind gutter systems. From there, the nuts get down into the walls. Don’t forget that once they are inside, these moths can infest a wide variety of products and materials. Pest management professionals should perform an inspection in the pantry areas and/or cabinets as well.

Q In a storage area in one of my accounts I have seen larvae crawling out
 from under the walls. They appear to be carpet beetles of some kind. What advice can you offer as far as control of these pests?

A The larvae this reader sent in were of carpet beetles. They are the common
 carpet beetle and belong to the Dermestid genera. These larvae feed on protein of all kinds from dead animals to feathers to wool. There has to be a food source in the wall for this infestation — probably dead mice if the pest management professional is also performing mouse control as most storage areas require. There also could be dead insects like cluster flies, but my money is on the dead mice.

My suggestion is to dust the void to kill the larvae. This problem will continue for some time if there are mice dying in the walls. Check other areas as the larvae also move away from the food sources and pupate. Once carpet beetles are established in the structure they show up from time to time, damaging a wide variety of products. Pest management professionals also can try pheromone traps to monitor for these pests.

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.