Sunday, September 20, 2009

Get out of my garden!

Something’s wrong.

It took a moment to realize what the matter was. Facing the steps I slowly descended loomed the 18-foot evergreen that greeted me each morning. But something was amiss. The needles had turned from their deep emerald hue to a sickly brown that reminded me of mud.

Stepping closer to investigate, I caught my first glimpse of them: they were beetles, chomping down on the once-perfect needles of my evergreen. They desiccated the tree: it was a living skeleton, hanging on by a mere twig.

The Japanese beetle, whose origins lie in Japan, is sometimes called the Japanese rose beetle for its inclination toward roses. It was first sighted in the US in 1916, according to the USDA. The beetle is about the size of a penny, with a copper colored body and metallic green head. It can fly, but clumsily. It usually sits upon a leaf, lazily chewing away at the greenery. The beetle is slow and easy to catch.

The Japanese beetle, or Popillia japonica Newman, has spread as far north as Ontario, and as far south and west as Georgia and Missouri (Popillia meaning scarab beetle, and japonica meaning "of Japan").

This pest devours all kinds of vegetation. They eat the leaves (or needles!), fruits and flowers of a wide variety of trees and plants. In the larval stage, the insect feeds on grassroots, causing obvious damage to lawns.

It flourishes in the US because of a favorable climate and ineffective natural predators. In Japan, the beetle is hardly an issue because of the natural predators that keep its population in check. Some species that attempt to reduce the beetle’s population in the US include starlings, Assassin bugs, and Tiphia wasps.

Because the effect of these predators is futile, several methods to eradicate the pest have been devised, including chemicals, traps, biological controls, and simple hand removal.

Several chemicals are available that would kill off either the adult Japanese beetle (Acephate), or the larvae (Imidacloprid). Though these insecticides produce rapid results, there is the chance the chemicals will be washed away as runoff, contaminating water sources.

Traps have been created for the beetle, with two intersecting panels of plastic, vertically crossing to form the shape of an ‘X’ if viewed from above. Below these pieces is a bag filled with pheromones. Beetles are attracted to the scent and fly into the plastic. Because they are clumsy fliers, they hit the plastic and fall into the trap, unable to escape. Though this is an effective method, it usually attracts more beetles in the area than were originally there, so place the trap far from your vegetables!

According to APHIS, a branch of the USDA, biological controls such as Nematodes, “microscopic parasitic roundworms,” can be used to control the beetle. This method takes longer to produce results, but is effective and environmentally friendly.

Arguably, the most effective tools to do away with the Japanese beetle are a thumb and forefinger. That’s right, go ahead and squish them! The bugs are slow, clumsy, and they don’t scurry away when approached. A homeowner can protect their valued crops with this inexpensive method of pick and squish, or, if looking for a more delicate technique, they can flick the beetle into a bucket filled with soapy water. Cover the bucket once filled with beetles, cover, and dispose of it once the insects have drowned.


  1. Hmm I'd feel bad squishing a beetle unless it was bothering me. But I guess it works best for people who have gardens. This is good advice for people with gardens.

    By the way, I didn't know nematodes were real.

  2. Nematodes ARE real. Haven't you ever that Neil Young song "I'd cross the ocean for a nematode"?
    Or is it heart of gold? Oh, never mind.

  3. Jenna, good info. What kind of evergreen was this. I am surprised that a beetle would feast on needles.