Several species of insects and other organisms that are generally not considered serious pests can invade a school building or become established on school grounds. These infrequent visitors may be present in landscaped areas but rarely cause significant issues in schools. Many occasional invaders are drawn to the school by the presence of food in the form of plant feeding insects, leaf litter and trash or sources of moisture from irrigated landscapes or shelter including mulch and other ground cover.
The elimination of conducive conditions that attract these pests is often the most effective approach to managing most occasional invaders. A few occasional invaders are more problematic and may become established indoors for a few days to several weeks.
Physical and mechanical measures may be required to prevent occasional invaders from accessing school buildings.
Table 1 Occasional invaders most likely to be encountered in and around schools.
|Common and species name||Geographic distribution|
|Asian lady beetle, Harmonia axyridis||Eastern and Midwestern US.|
|amphipods or scuds, Class Crustacia, Order Amphipoda||Throughout the US.|
|booklice, Liposcelis corrodens||Throughout the US.|
|Boxelder bugs, Boisea trivittata||Midwestern and West Central US.|
|centipedes, Class Chilopoda||Throughout the US.|
|clover mite, Class Arachnida, Order Acari||Throughout the US.|
|crickets, Gryllus spp.||Throughout the US.|
|earwigs, Order Dermaptera||Throughout the US.|
|firebrats||Throughout the US.|
|fleas||Throughout the US.|
|millipedes, Class Diplopoda||Throughout the US.|
|pillbugs and sowbugs, Class Crustacea, Order Isopoda||Throughout the US.|
|slugs and snails, Class Gastropoda||Throughout the US.|
|snakes||Throughout the US.|
|scorpions, Class Arachnida, Order Scorpiones||Throughout the US.|
|silverfish||Throughout the US.|
|springtails, Order Collembola||Throughout the US.|
|stored product moths and beetles||Throughout the US.|
|wood-boring beetles||Throughout the US.|
Occasional invaders are a very diverse group. Although many have common requirements for food, water or shelter, identification of the individual pest is required whenever one of these occasional invaders is found in a school. Any insects or other arthropods that are collected for identification purposes should be placed in a vial instead of plastic bags or tape to preserve key identifying characters.
Adhesive-coated traps are the best monitoring method for most occasional invaders. For some, special traps are available including pheromone traps for stored product moths and beetles.
Inspections for occasional invaders should be focused around doorways and at the exterior perimeter of the building, particularly in areas where vegetation is present close to the structure.
Overwintering occasional invaders such as boxelder bugs or Asian lady beetles enter school buildings in late summer or early autumn through cracks or openings under siding, around flashing, or through weep holes. These insects congregate in voids such as attics or crawlspaces. In the early spring, during periods of warm weather, they may be observed on window ledges or emerge from around light fixtures.
Cultural, physical and mechanical management options are preferred and include eliminating harborage and excluding outdoor pests from entering buildings. Vegetation should be trimmed so that it does not contact structures and mulch should be raked away from the structure. Moisture around buildings should be reduced by repairing gutter systems, improving site drainage, and ensuring irrigation is directed away from building foundations. Sealing potential entry points such as gaps around pipes and other service penetrations in exterior walls or sealing gaps under doorways are good exclusion techniques for occasional invaders.
Table 2 Commonly used products for physical, cultural or mechanical management of occasional invaders and uses.
|door sweeps and seals||Sealeze® Weatherseal||Close gap between bottom of door and sill, and between edges of door and frame.|
|insect monitors, glue boards||Catchmaster®||Install near potential entry points and harborages to reduce populations/intercept individuals.|
|window and door screens||many||Install over windows and doorways.|
Pesticides are rarely necessary for occasional invaders. However, if established populations are present in exterior perimeter locations and non-chemical methods are unsuccessful in achieving adequate control, crack & crevice or spot applications of a least-toxic product may be required. These treatments should be directed into suspected harborages for the specific pest.
Pesticide treatments are not recommended for overwintering occasional invaders that are present inside a building.
Pesticide options that reduce potential for exposure include insecticide baits in enclosed bait stations. A limited number of effective baits are available for specific occasional invaders. If granular baits are needed, these should be used in tamper resistant bait stations.
Pesticide options that increase potential for exposure for students, staff and other facility users include spray formulations applied to exposed surfaces or broadcast granular products.
|Active Ingredient||Example Products||Uses|
|boric acid||Borid® 9444-195||Dust formulation. To reduce exposure hazard, use only in voids that will be sealed after use.|
|diatomaceous earth||Concern® 50932-12||Same as above|
|disodium octaborate tetrahydrate||Boracide® 64405-7||Same as above|
|orthoboric acid||Niban Granular Bait® 64405-2 Provaunt® 352-716||Granular formulations. To reduce exposure hazard, use only in voids that will be sealed after use.|
|indoxacarb||Advion Mole Cricket Bait® 352-651||Same as above|
|boric acid||PT 240 Permadust® 499-384||Pressurized aerosol.|
|Active ingredient||Example Products||Uses|
|bifenthrin||Talstar® 279-3225||Liquids spray applied to exposed interior or exterior surfaces. Reduce exposure by using these products in cracks and crevices only.|
|chlorfenapyr||Phantom® 241-392||Same as above|
|cyfluthrin||Tempo® SC Ultra 11556-124||Same as above|
|cypermethrin||Demon® EC 100-1004||Same as above|
|deltamethrin||Suspend® SC 432-763||Same as above|
|lambda cyhalothrin||Demand® CS 100-1066||Same as above|
|rosemary oil||Ecoexempt® 2C 67425-20||Same as above|