Most of us use SHB traps with screen bottom boards. Rossman Apiaries makes the model B30-90 that I use. They do an excellent job on the adult form of the beetle. However, the SHB has stages in the life cycle. We have egg, larva, pupa, and adult. The female adult lays eggs. The eggs become larvae. The larvae cause massive destruction in the hive, then leave for moist soil to pupate. The pupa becomes an adult, and the cycle is repeated.
The larva to pupa stage occurs outside the hive. Thus, an opportunity to disrupt the cycle presents itself.
Soil drenches such as GuardStar exist that kill the soil-borne larvae. However, such drenches are very dangerous and also easily kill bees. An alternate plan of attack is needed. Scientists have done much research on beneficial nematodes as a possible solution.
BNs are microscopic round worms that naturally occur in many soils. Different species of BNs attack different larvae. Steinernematidae and Heferorhabditidae nematodes attack and kill several garden pests, including SHB larvae.
In brief, the BN package is mixed into a water can and sprinkled into the soil around the beeyard. The BNs burrow into the soil and find the larval stage of the SHB. They enter the body of the SHB larvae and release a bacterium that dissolves the flesh of the larvae, killing it. The BNs feed on this mess and reproduce within the larva corpse. The BNs then hatch out by the hundreds of thousands and seek additional food (SHB larvae). This cycle continues so long as a food source for the BNs is around. (BNs also eat the larvae of fleas, Japanese beetles, and white grubs).
In order to have success with BNs, specific steps must be followed. David Shapiro Ilan of the USDA Agricultural Research Service report a 78% kill rate for SHBs in the February 2010, issue of the Journal of Invertebrate Pathology.
I found that SoutheasternInsectaries.com sells BNs specifically for SHB control. A package of 5 million nematodes is $25 plus shipping. A package is designed to treat a 210 square foot area around the beeyard.
I called Phillip Tedders of Southeastern Insectaries and he was very helpful. He recommended putting out BNs in the early morning or at dusk to avoid the heat of the day. BNs can be applied in spring, summer, or fall.
The BNs are shipped in an insulated container. A cooling pack is inserted if the temperatures are expected to get above 89°F. Right now, he recommended shipping in FedEx overnight because of the high temperatures. He also recommended using a low pressured microscope to examine the BNs upon arrival to make sure they are still alive.
The BNs should be applied to moist soil. You take the plastic package and strain the contents through a tea strainer into a five gallon bucket, using five gallons of water to rinse the BNs into the bucket. Transfer to a regular water can and apply. It is best to apply the liquid to all soil within three feet of the hives. Also apply it under the hive if you can.
BNs have a shelf life. Call to make sure they have fresh ones in stock. Try to use them within a week of getting them and store the bag in a refrigerator (not freezer!) until you are ready to water them in.
It was clear to me that Mr. Tedders believes in his product. It is probably too hot now to apply the BNs until the cool of fall. Still, this is an interesting weapon in the arsenal against SHBs and is worth an application if one can follow the moisture and temperature requirements. Southeastern Insectaries can be reached at 1(877) 967-6777.
Written June 14, 2012
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