Practical pest prevention for Minnesota schools

Important steps

• February: Plan to protect! Review past problems with pests.
• March or April: Inspect problem areas for early pavement ants.
• May: Leaves, litter and landscape. Check the building for cracks and gaps.
• June: Pavement ants and carpenter ants
• August: Pavement ants and carpenter ants. Inspect classrooms for ant activity.
• October: Leaves, litter and landscape.
• Teacher information: Report those pests.

Plan to protect: Review past problems and sightings of pests in the school

During the Plan to Protect step, create a list of places where ants have been reported in the past. This will be the starting point for preventing future pest issues.

Early pavement ant inspections

In March or April, look in the areas where ants were previously reported. Pavement ants have the ability to live around building foundations or underneath concrete slab-on-grade construction. In spring, there may be a flush of winged ants as the ant season kicks off. Inspect areas for ant activity and vacuum up evidence of old ant activity, as well as food particles that may encourage ants to remain in the area. If ants are found conduct control measures as outlined in the Control Methods section, below.

Leaves, litter and landscape

Leaves and litter in the landscape around schools provide many species of ants with areas to form a colony and ultimately enter a facility. There will be food available in these areas as well. At the very least, make sure there is no accumulation of trash and plant material around the school. It would be better to replace any ground-spreading plants (such as yews), especially if the school is continually challenged by ants. Loading docks and garbage dumpsters are particularly prone to having litter and food accumulate in or near them creating a pest-friendly area.

Check the building for cracks and gaps

Buildings that settle, new construction, and utility lines into the building (gas, electric, etc.) have gaps and cracks that open the school to pest invasion. An annual inspection and rechecks, whenever pests occur, will ensure that pests are not entering the school. Remember, some of these cracks and gaps may be underground and in the foundation.

Summer ant inspections

The summer is when ant colonies begin to grow and there is an increasing need for food, water and space. Many ant species will begin to explore around the structure. Some of the ants will have their colonies in the landscape (e.g., carpenter, pavement, and field ants) and a couple of species may be inside the building (pavement ants). Respond to reports from staff and quickly check the areas where ants have previously appeared. Catching ant activity early means they can be prevented from becoming widespread.

Inspect classes for ant activity

Prior to the start of the school year, make sure there are no active ant infestations in the school. With a flashlight, inspect corners, cupboards and behind equipment for signs of ants. Remember to check ledges, edges and lines. Pests prefer to travel around the room perimeters and along edges, staying hidden as much as possible.

Responding to teacher and staff reports

Responding to a pest sighting is not just about applying some pesticide and reducing the number of pests. By being present, the pests are telling you that they have found the suitable habitat they need to survive and grow. Ask yourself and your pest management professional: “Why are these pests present?” The answer could be food, or hiding places or water. Knowing why they are present will help you determine how to permanently fix the situation.

Control methods:

Ants can be controlled by four easy steps:

1. Clean up any infested food or carefully vacuum any food residue that the ants may be using. Remember that ants eat many things that we might not consider food, such as skin flakes, other insects, food crumbs, etc.

2. Apply a residual insecticide into the cracks or crevices where ants are present (follow the insecticide label). Then seal the hole or crack that they are using. If the building exterior is brick and the “hole” they are using is actually a weep (or vent) hole, do not seal the hole but install pest screening.

3. If you are having difficulty in finding holes that the ants are using, the area is difficult to access, or the access points are widespread, consider using an insecticidal bait in the area (follow the use directions on the insecticide label).

4. Work with your pest management professional to determine if any other issues require correction to reduce or eliminate ant activity.

Download a print version of these steps to help you during an inspection.

Important steps

• February: Plan to protect! Review past rodent problems and sightings.
• March: Inspect door sweeps and install 2-3 door sweeps per year. 
• May: Leaves, litter and landscape. Check buildings for cracks and gaps.
• August: Inspect classrooms for rodent droppings.
• October: Leaves, litter and landscape.
• Every month: Have rodent traps inspected in refuse areas, mechanical and cafeteria and kitchens.
• Teacher information: Report those droppings. Open doors help pests infest.

Plan to protect: Review past problems and sightings of rodents in the school

Create a list of places where rodents have been captured, reported or where their feces were found. In any area, more than one mouse report in a month or more than three reports during a year means there are likely other rodents or hidden pathways they can use. If this occurs, additional pest control and prevention measures will be needed.

Inspect door sweeps; install 2-3 new door sweeps per year

Maintained door sweeps will stop most mice from entering the facility. However, it is often challenging to budget door sweep replacements for the whole school. Begin with 2 or 3 door sweeps in areas where rodent activity has occurred. Over the next years, door sweeps can be added until the entire facility has properly installed sweeps.

Leaves, litter and landscape

Leaves and litter in the landscape around schools protect rodents during their attempts to enter a facility. Reducing leaves and litter mean that rodents will have to shorten their visits in favor of safer areas. At the very least, make sure there is no accumulation of trash and plant material around the school. It would be better to replace ground-spreading plants (such as yews), especially if the school is continually challenged by rodents. Loading docks and garbage dumpsters are particularly prone to having litter and food accumulate allowing a pest-friendly area.

Check building for cracks and gaps

Buildings that settle, new construction, utility lines (gas, electric, etc.) into the building have gaps and cracks that open the school to pest invasion. All gaps and cracks 1/4 inch or more in diameter should be properly sealed. An annual inspection and rechecks, whenever pests occur, will ensure that pests are not entering the school. Remember, some of these cracks and gaps may be underground and in the foundation.

Inspect classrooms for rodent activity

Prior to the start of the school year, make sure there are no active rodent infestations in the school. With a flashlight, inspect corners, cupboards and behind equipment for the signs of rodent activity. Mouse droppings will likely be the first indication that a rodent is present. Remember to check ledges, edges and lines. Pests prefer to travel around the room perimeters and along edges, staying hidden as much as possible.

Control methods:

If you have a rodent infestation you should work with your pest management professional to create a plan for eliminating rodent activity in your facility. In addition to using traps, you should eliminate the things in the environment that are attracting rodents. Removing food, water and harborage is a very important step. 

The most common and effective way to control rodents is with traps. There are some important things to remember when trapping rodents:

• Traps should be placed in pairs and along ledges, edges and lines.

• A common mistake in mouse control is to set too few traps. Traps should be set in areas of rodent activity, but also in adjacent areas to detect the presence of hidden mice.

• When you see a rodent in a school, this animal may be living on the fringes of a larger infestation. Careful inspection is necessary to ensure a larger infestation is not occurring. Continued trapping may be necessary to ensure all mice are harvested.

• Look above false ceilings (if present) for droppings. This is an area often used by mice but seldom checked by people.

• Rodents (even mice) may recognize and avoid traps. You should use a variety of trap baits to attract rodents. It may be necessary to keep traps unset so that mice become reliant on this new food source. Working with your pest management professional to establish a trapping plan will ensure the highest rate of success.

Download a print version of these steps to help you during inspection.

Important steps

• February: Plan to protect! Review past problems with pests.
• June: Manage flowering plants.
• July: Check for nests on the building or in the ground.
• August-October: Trash bin maintenance.
• Teacher information: Report those pests.

Plan to protect: Review past problems and sightings of pests in the school

Create a list of places where wasps or bees have been reported in the past. This will be the starting point for preventing future pest issues.

Flowering plants

Throughout the summer, flowering plants will attract nectar-feeding insects, such as honey bees, solitary bees and bumble bees. Avoid using insecticides because bees are important for crop pollination and some insecticides picked up by foraging bees may affect the whole hive. If there is a risk of bee interaction with students or staff, there are three simple practices that can be considered to reduce this risk:

1. Remove the flowering plants and provide plants that are less attractive to bees. Seek the advice of a horticulturist in the area.

2. Relocate these plants away from student and staff activity.

3. Restrict student access. Have school administration prevent student access to gardens while the plants are flowering.

Check for nests

Depending on the species, wasps and bees may nest on buildings and trees, or in the ground. If they are nesting on buildings they will find protected areas where the weather will not affect them. Checking the building overhangs, near doors, and eaves will allow for the early detection of nests.

Ground-nesting wasps and bees will form nests in bare patches in turf, under landscape plantings or next to hardscape items such as railway ties, stones or concrete walls. Ground-nesting wasps and bees are harder to detect, but a careful inspection in areas of high student and staff activity will reduce most interactions.

Trash bin maintenance

In late summer and early fall, wasp activity will increase around trash bins and dumpsters as natural food sources (e.g., aphids and other insects) begin to decline. Wasps may become more aggressive in traveling to food sources in an attempt to support a colony that has flourished over the summer. Increase the frequency of trash collection during this time and clean up any spillage around the bins.

Respond to teacher and staff reports

Responding to a pest sighting is not just about applying some pesticide and reducing the number of pests. By being present, the pests are telling you that they have found the suitable habitat they need to survive and grow.

Ask yourself and your pest management professional: “Why are these pests present?” The answer could be food, or hiding places or water. Knowing why they are present will help you determine how to permanently fix the situation.

Control methods:

It is critical to get an accurate identification of the bee or wasp that is causing the problem. Correct identification will ensure the safe, effective and economical use of prevention and control measures. Below are some general steps for reducing the risk of bee and wasp issues.

• As mentioned, the management of landscape plantings will reduce most bee and student interactions.

• Regular inspections during the summer will detect potential problems earlier, nests will be smaller and more easily controlled with less insecticide.

• DO NOT use a ladder while approaching a nest, unless you are using protective gear. Injuries commonly occur when people fall from ladders to get away from aggressive wasps.

• For nests on buildings, use a short-acting insecticide such as Wasp Freeze® or a similar product that allows you to remain at a distance while applying the insecticide. If you do not want to spray insecticide from a distance, there are extension poles that permit closer placement of the spray can to the nest.

  • Apply treatment when no children are present.

  • Once control has been achieved, use a water stream to knock down the nest.

  • Dispose of the nest by sweeping it up and sealing it in a plastic bag.

• If the wasps or bees are nesting inside the building, consult a pest management professional. A dust or residual insecticide will need to be applied into the cracks or crevices the insects are using (follow the insecticide label). Also, the size of the nest and how far it extends into the building will have to be determined. Nest removal may be necessary to prevent other pests, such as dermestid beetles or mice. Removal of bee hives is particularly important because the honey from large hives may seep through walls resulting in odors and more extensive damage.

• If the wasps or bees are nesting in-ground and their activity is close to students, consult a pest management professional. Some solitary wasps will simply nest in bare patches in the turf, while colonial wasps and bees will be deeper in the ground. For colonial insects, wasp sprays will kill some insects, but the actual colony will have to be treated to prevent further activity.

• For chronic or repeated infestations, work with your pest management professional to determine if any other issues require correction to reduce or eliminate wasp and bee activity.

Download a print version of these steps to help you during an inspection.