[Technically Speaking] Tough problems - no easy answers

If you have been in the pest management industry for a few years you probably have encountered a few of those puzzling pest problems that defy explanation and are tough to solve. This article is not intended to present all the solutions to unique problems but provide some food for thought and provide information on how to manage some infrequently encountered pests.

MILLIPEDES. One of the most unique and frustrating problems we encountered during the past two years were millipedes in a fourth-floor apartment of a recently remodeled upscale apartment building. The building had a brick veneer up to the fourth floor level, air handler units that opened to the exterior and enclosed balconies. The landscaping was heavily mulched.

The problem first occurred two years ago at the end of summer and involved one fourth-floor apartment and one totally freaked out tenant who was killing five to 10 millipedes per day. We performed the requisite inspections, applied product in the balcony area (around the air handler), and in open pipe chases and wall outlets. Maintenance did some extensive sealing. We cleaned a slit drain at the garage entrance that had several years of accumulated organic matter and hundreds of millipedes. In retrospect, with our treatment and a lot of key timing (the end of summer), the problem abated until this spring when more apartments on the same tier began having the problem.

During our inspection this spring we saw hundreds of millipedes crawling all over the sides of the building, particularly on the north side and up to the fourth floor, mostly attributable to periods of drought and heavy rain. We recommended removing the mulch, turning off the irrigation system to allow the ground to dry out, and treatment with liquid and granular insecticides. After treatment with fipronil and several pyrethroids, the activity in the fourth floor unit and several lower units persisted. Unfortunately, these products did not seem to appreciably decrease the population.

A closer inspection of this area indicated the millipedes were entering through gaps around the windows, weep holes and gaps around the air exchange unit. Thus, we undertook a sealing job in all these areas using Stuff-it, weep vent material and caulk to minimize penetration of the building envelope. After a little research on university extension Web sites, I found several recommendations to use organophosphate or carbamate products for millipedes. The only product immediately available for our application site and situation was carbaryl (Sevin). Two treatments with Sevin, sealing exterior openings and correction of conducive environmental conditions appear to have solved the problem. Only next spring will tell.

SILVERFISH. This insect is the nemesis of even the best pest management professionals. Silverfish have adapted well to the structural environment. This adaptability leads to their movement throughout the structure as conditions change. One of the first questions we typically ask a customer calling about silverfish is if their home has cedar shake siding and/or shingles? Frequently, this is a major source of infestation with silverfish migrating to the roof and walls in the cooler months and into the attic and remainder of the home during the summer.

Some other common infestation areas include wall and ceiling voids, pipe chases and under tubs. The most problematic areas are boxes used to store papers, photos, books and other paper goods. Silverfish are not commonly found in overwhelming numbers in a single location but tend to be distributed randomly throughout the structure. The use of monitors can aid in detecting areas of activity. Unfortunately, visual inspections are rarely effective in discovering activity.

Silverfish in roofing shingles and insulated attic spaces are the most difficult to control because of inaccessibility. For instance, cedar shake shingles are difficult (if not impossible) to treat without getting on the roof, which is dangerous for the technician. Also, walking on shingles can damage them. On the rare occasion we have performed these treatments, they have proven to be less than satisfactory. The best results we have achieved in treating roof areas (and attics, particularly those with insulation) have been to use a broadcast treatment of the entire area with a fine granular boric acid bait. This material also can be applied in boxes and filing cabinets where silverfish are found.

This bait is also effective when applied to wall and ceiling voids, pipe chases, along baseboards and other dry areas. Dusts also are effective when applied here. Consider an appropriate dust if the area is occasionally damp. Generally, we have not found sprays to be effective in controlling silverfish.

SPRINGTAILS. If you ever get a call for jumping insects in a structure, there are no biting complaints and no history of pets or wildlife in or near the structure, the most likely culprit is springtails. And while these common outdoor insects may seem easy to eliminate, we have seen several cases in the past that were extremely challenging.

Typically springtails are found outdoors under tree bark, around the foundation in grass, mulch, and/or stones, in basements, inside wet walls, and other areas that offer protection, moisture, and fungal growth. We have encountered two difficult problems to treat, i.e., an infestation in an exterior wall from the basement to the second floor and a basement infestation in the expansion joint and possibly the French drain.

Controlling moisture on the exterior and in walls is the most important consideration in dealing with springtail infestations. If the source of moisture can be corrected it still takes a significant amount of time for the area to dry out and the infestation to diminish. When most of the springtails are located outside the foundation, treatment with a residual insecticide will significantly reduce the population. In our experience, the most effective product contains carbaryl.

A variety of products are effective in controlling springtails once they are inside the walls or under the slab in the basement. A moisture meter is essential for identifying areas in the walls to be treated. We have found foam injection to be the most effective way to treat these areas. Normally, treating the expansion joint and using a dehumidifier will resolve most springtail infestations and pose little environmental risks. It is necessary to proceed with caution when treating basement slabs with pyrethroid insecticides, particularly if there is a French drain. The drain may discharge into a stream or storm water drain that may lead to a larger body of water containing fish which are easily killed by very small amounts of the product.

CONCLUSION. The greatest challenges in pest management come from those pests that are the most unusual. To me, the greatest satisfaction is derived from solving that tough problem for your customer.

The author is president of Innovative Pest Management, Brookeville, Md. He can be reached at rkramer@giemedia.com.