North American Fruit Explorers mailing list at ibiblio

[Joe Hecksel <jhecksel@voyager.net>]

Hi all:

This is purely speculative.  Please do not bet the farm on the following post.

One of the facts that has always intrigued me is that the Carpathian walnut trees at Mom and Dads rarely have borers or maggots.  Mom and Dad live IN the city of Lansing, Michigan....a metropolitan cluster of approximately 250,000 souls.

I live in a second suburb ring of that cluster.  Lansing is a weak metropolitan cluster.  Like Saturn (the planet), there are gaps between the first and second rings.  That is, there are still corn fields between the first ring of suburbs (Holt, East Lansing, Waverly, De Wittless) and the second ring.  My Carpathian Walnuts are hammered by insects. I have walnut borers up the wazoo.  The few walnuts I get all exhibit husk maggot damage.

What is the difference?  Maybe it is pollution:  Light pollution.

Many nocturnal insects navigate by light; by moon light.  Urban areas have a poverty of moths and other nocturnal insects due to the effect of "security" lights.  Those lights baffle and confuse moths. Mercury vapor lamps are the worst because they closely mimic the spectrum of moonlight.  They suck them in and don't let them go.

The Proposal:

Put a standard bird bath underneath your walnut trees (or fruit trees).  Put a white plate in the bottom of the bird bath.  Fill with water in the usual way, but add a few drops of dish detergent to the water.  Aim an LED flashlight from a tree limb so it shines on the white plate in the bird bath.  (LED flashlights are amazing.  Some of them will work on 2 AA batteries for 200 hours and can be purchased for $15 from Big-Box stores)  Turn the LED flashlight on when you start to see borer and/or maggot activity.  Continue for approximately 2 weeks, changing batteries as required.  Change water as moths accumulate and obscure plate.

OK, I did not invent this technology.  I ran across it while crawling around the WWW.  This method was being used in Thailand to protect crops.  I tried to find the site again, but was not successful.  Otherwise, I would attribute credit where due. 

Obviously,  the nocturnal insects mistake the white plate for the moon and plunge into the water.  The reason for restricting the practice to two weeks is that this technique is devastating to all moths....not just the bad guys. 

An alternate approach is to mount a compact  Fluorescent bulb (15 watts should be plenty) above the canopy and feed the bats.  As stated before, limit the practice to the 2 weeks of peak pest activity to minimize impact on non-pest species.

Comments will be much appreciated.