Field of Science

Japanese beetle invastion - 2009

Japanese beetles have extended their range into my local portion of Lincolnland in just the past 3 or so years much to the dismay of gardeners. And the Phactor is not immune; his gardens are being consumed as much as everyone else's. So what can you do?

Japanese beetle traps are not the answer. Studies have shown that such traps can attract way more beetles than they kill, so while you may feel good about all the beetle bodies piling up, the local population may be higher than it would be without the trap.

Spraying plants with insecticide is not really the answer either both because no one likes spreading such nasty stuff around, especially on plants that you are planning to consume, but in small gardens, the beetles still cause intolerable damage. Last year they denuded two young apple trees while I was away for a long weekend. If the trees were sprayed, the beetles would eat until the toxin kills them and then they would be replaced by more beetles who eat until the toxin kills them, and so on until my trees are again denuded. Since the object is to prevent the trees from being eaten, not to kill beetles, this year the Phactor took another approach. Evaluation is continuing.

Light weight netting can be purchased at many fine fabric stores; the ladies are usually quite helpful. So far the netting tents over the young apple trees, held in place by extremely high tech clothes pins, seem to be doing an excellent job of thwarting the voracious beetles. Finer wedding veil voile could also be used to protect green beans or cucumbers from the small beetles that they attract. In the case of the cucumbers it isn't that the beetles eat so much but they transfer a wilt causing bacterium that invariably kills the cucumber plants (and their close relatives, cantelope).

Such netting is quite cheap, a nice alternative to more expensive row coverings.

Do the readers of the Phytophactor have other anti-Japanese beetle methods they would like to share?

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