Good News for Gardeners

Jim Long, Copyright 2012

It seems time for some good news for gardeners for a change. With everyone's tomato plants hung with sheets to block the sun to prevent sunburning on tomatoes and making gardens look like a backyard laundry, I decided to go looking for something to be glad for. (By the way, sheer curtain panels from the thrift shop are my favorite covering to keep birds away from tomatoes and preventing sun-scald on the fruits).

Sheer curtains covering tomatoes to keep from sunburning the fruit.

Here’s something to make this weeks garden chores just a little more pleasant. Every time you see a cluster of Japanese beetles eating your roses, squash blossoms or other garden plants, you can smile and know the bugs have some bad news in their futures.

Japanese beetles were accidentally introduced into the United States in 1916 near Trenton, NY. Japanese beetles have now spread into every state east of the Mississippi River. They’ve spread as far west as Denver - although the current forest fires in Colorado are certainly making the pests’ lives more miserable.

It’s been known since 1920 that Japanese beetles can be temporarily poisoned by geranium flowers - yes, those same geraniums that are probably in pots on your patio! But no one studied how or why geraniums effect the beetles until recently, when scientists at the Agricultural Research Service (ARS) in Ohio began working on the question.

Here’s what they know so far. When a Japanese beetle eats a couple of geranium flowers - any color will do - the bug is paralyzed for about 12 hours, belly up, legs twitching in the air. This leaves it exposed to predators like birds, dogs and the heel of your shoe.

Chris Ranger, an entomologist at AHS is working on a natural, botanical formula for controlling the beetles based on compounds isolated from geraniums. Once the formula is up and working, it will be patented as a spray and we’ll all have access to it. Progress is looking very good!

Other controls available already include the product, Milky Spore Bacteria, which you spread as a powder on your lawn and garden, the bacteria infects the grub stage of the beetles and kills them before they hatch. After 2 seasons of spreading this powder throughout my lawn and garden, I have fewer beetles this year.

Another control that works is the Spring Tiphia wasp, which is an effective biological control for the beetle. You can order the Tiphia larvae and release them into your garden where they go to work on the grub stage of the Japanese beetle. (The “wasps” are tiny, you’ll likely never see one and they have no interest in humans or pets, and don’t sting unless you’re a beetle).The Tiphia wasp is attracted to peonies, so planting those will help bring them naturally to your yard.


(Note: read this discussion on a gardening forum that isn't as encouraging as what I've heard recently. You'll see that the discussion was posted in '04, so opinions may have changed about Milky Spore Bacteria results. I think I have positive results, however it could also be weather conditions that have lessened my Japanese beetle population this year. Also, it's discouraging to hear the parasitic wasp larvae are so expensive, hopefully the link I gave above "order the Tiphia larvae" can be of some help).

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