How Could IPM Have Helped?

San Ysidro School District, San Diego, California is battling an unresolved lawsuit over alleged pesticide use, incurring $35,000 in legal costs as of last month. According to media reports, in 2011, teacher Josie Hamada took her students to a cherry tree grove on school property to draw and write about trees. After clearing some weeds, Hamada found herself contaminated with a blue substance which she suspected was a pesticide. Students were quickly moved inside to wash up. Health complaints followed, including at least one student’s trip to a hospital the next day.

School officials report that no pesticide had been applied by district staff or contractors, and claimed that notices are posted for every scheduled application. The district had also sent out 5,000 notices to parents asking if they wanted to receive individual notification when the school applied pesticides; only three parents responded.
Media reports indicate the cherry trees were planted as a memorial to September 11, 2001 victims. It’s unclear from the news stories if the blue substance was confirmed to be a pesticide, however an informed IPM coordinator might have suggested a lower maintenance alternative before the trees were planted. Cherry trees, much like apple, crabapple, dogwood and birches, are “key plants”, prone to insect and disease problems. In most environments, cherry trees and other key plants require interventions, including pesticide applications, to keep them healthy and attractive. Fruit trees also typically shed some of the crop throughout the growing season, which can provide a food and moisture source for rodents, flies, yellow jackets and other potential pests. Weeds can also be a challenge to manage. Barrier fabric and mulch can be a solution, but can also provide harborage for rodents, and requires ongoing maintenance to be effective. To real the full story, click here.

Red imported fire ant mound
(Jake Farnum, Bugwood.org)

In Texas, a student died at Has Middle School in Corpus Christi following an allergic reaction to fire ant stings he received on a football field. While the district has some IPM tactics in place, their IPM practices for fire ant management were not complete. The coaching staff was not trained to recognize the signs of anaphylactic shock.  Knowing when and how to inspect a field for fire ants and how to apply baits effectively are key to fire ant management.

According to Janet Hurley, Extension Program Specialist, Texas A&M AgriLife Extension, “Your objective should be to find the method or methods that are most cost-effective, environmentally sound and fit your tolerance level for fire ants.” AgriLife Extension worked with the school IPM staff to develop a district-wide fire ant baiting program. One year later the district has reported fewer fire ant complaints and reduced cost with a broadcast bait program rather than treating individual mounds, which is time intensive, can require more pesticide use, and does nothing to manage fire ants foraging from mounds on adjoining property. Properly timed bait applications can be entirely consumed by foraging ants within hours, limiting potential for exposure to the bait. The district also adopted a policy to train all staff on how to recognize anaphylaxis and how to properly respond to an allergic reaction to both pests and food-borne allergies. Read the full story here. To learn more about fire ants and IPM visit Fire Ants and the Texas IPM in Schools Program.

Ground Bees Active But Pose No Threaten to People or Yards, by Steve Frank, NCSU Extension Entomologist

As I write this my front yard is abuzz with small bees. Many are flying around just above the ground while others fly back and forth to redbuds and camellias gathering pollen.

Although these bees do not generally sting, I watch as mothers nervously cross the street with strollers. Neighbors pass by and comment "Watch out for all those fire ants" referring to the small mounds that dot my sparsely vegetated lawn. Others offer suggestions on how to rid myself of these dangerous beasts that are "tearing up your lawn."

The bees I am watching are ground nesting bees in the family Andrenidae. All the species in this family are solitary and nest in the ground. Solitary means they do not maintain vast hives with hundreds of workers like honeybees or yellow jackets. A single female bee builds the nest by burrowing into the ground. She prepares larval cells where eggs will be laid. Mothers provision each brood cell with a mixture of pollen and nectar (called bee bread) that serves as food for young larvae. After laying an egg she closes the brood cell and starts another. After completing several brood cells the mother will seal the entrance and leave the nest to begin a new nest. After a few weeks she will die leaving the next generation safe in the ground.

Bee emerging from its mound (Photo: S.D. Frank).

In the spring, bees complete development and emerge as adults that dig their way out of the ground and forage for pollen and nectar to provision their own nests (see photo above). The visual spectacle of these bees is produced largely by males who swarm over nests trying to mate with newly emerged females. The other noticeable aspect of these bees is the small mounds of dirt excavated for each nest.

Hundreds of small mounds created by bees.

Hundreds of small mounds and swarms of bees often trigger calls to exterminators or landscape professionals (see photo at right). Homeowners fear that they will be attacked and stung as they bend over to pick up the paper and they believe that the bees are actively damaging their yard and want them gone. This is not the case.

An ovipositor is the organ female insects use to insert eggs into substrates such as leaves, wood, soil, other insects, or in our case brood cells. In social insects such as honeybees, most of the females are workers that do not mate or lay eggs and thus have no need for an ovipositor. However, they do need to protect the nest from invaders. Therefore, the ovipositor of these social species has evolved into a stinger to ward off threats.

With this in mind it is easy to understand why the threat of being stung by the ground nesting bees in my yard is so small. First, the bees swarming around are mostly males. Males don't lay eggs and thus do not have an ovipositor, modified or otherwise. The female bees are responsible for all aspects of nest construction and provisioning and are busy digging and foraging. Since the ovipositor of ground nesting bees is necessary for laying eggs, it is not well developed as a stinger, if at all. I won't say that you will never be stung because this would encourage some fool to torment bees until they proved me wrong. However, I have handled these bees quite a bit and have never been stung (see photo below).

Bee held safely for a portrait (Photo: S.D. Frank).

These bees prefer to nest in dry, sparsely vegetating areas. Therefore, if you have bees nesting in your lawn it is because the grass is thin and the soil is dry. The bees don't make it this way, they just take advantage of the conditions. If anything the bees are providing a valuable service by aerating the lawn!

The behavior and habitat preference of these bees leads us to the most promising ways to reduce their abundance in a particular yard. First they like dry soil they can dig nests in. Therefore, irrigation over the 3-4 weeks bees are active will encourage them to find other nest sites and reduce their abundance the following year. In addition, they like thin lawns with plenty of bare spots. Thus, you can take measures to improve the density of your grass to make it less appealing to bees. Native bees are an important part of ecosystems and food production. We should take steps to protect these bees or at least use non-lethal means to encourage them to nest somewhere else.

Termites Swarming

We are already starting to get reports of termites swarming. Just last week, we had termites swarm in a building on NCSU campus. You may have already experienced some swarms in some of your buildings. Eastern subterranean termites generally swarm from late-February to May. Swarming usually occurs during the day, particularly on warm days following rain. Swarms occurring outdoors near tree stumps, landscape timbers, etc., are not an indication that a structure is infested, but simply serve as a reminder that termites live around us. However, when swarming occurs indoors, it usually means that there is an infestation somewhere in the building.

If you have an indoor swarm, simply suck up the swarmers in a vacuum cleaner. Place the vacuum bag inside a plastic bag and seal it before disposing of it. There is no real need to spray them; plus spraying in this situation would require notification. There is also no need to rush treating the building. This situation would not be considered an emergency. Plan the treatment for a teacher workday or holiday when that part of the building is or can be vacated. The treatment will vary depending on where the termites were found swarming. A spot treatment may be all that is needed and will not be as expensive as a full treatment of the structure.

New brochure on IPM for Schools and Child Care Facilities

A collaborative effort between NCSU, Texas A&M and Syngenta has produced this new IPM publication - "An Ounce of Prevention!" covering IPM for Schools and Child Care Facilities. 

"AN OUNCE OF PREVENTION" Brochure