Entomologist answers borer ?s
- To: Multiple recipients of list <i*@rt66.com>
- Subject: Entomologist answers borer ?s
- From: "* L* <V*@calc.vet.uga.edu>
- Date: Thu, 6 Nov 1997 15:29:28 -0700 (MST)
Subject: Re: Nematodes for iris borer questions
Dr Sparks writes:
My comments are in CAPS following.
1. Are nematodes consumed orally by the borer/grub, or do they penetrate
the grub's "skin?"
MOST NEMATODES ENTER THE INSECT THROUGH THE MOUTH, ANUS, SPIRICLES OR
WOUNDS
If it is the latter (which would be a logical means for a soil
borne parasite to enter a soil inhabiting larvae), I'm skeptical that
a foliar application could be effective.
THE NEMATODES NEED MOISTURE TO MOVE ... EITHER SOIL OR LEAF
MOISTURE..
2. How long can a soil-inhabiting, parasitic nematode remain
viable, exposed to sunlight, heat, and so forth on the surface of a
leaf?
THEY DO NOT SURVIVE VERY LONG (HOURS) IN THE ABSENCE OF MOISTURE.
3. How do these suppliers go about isolating these specific
nematodes?
THEY ACTUALLY MASS PRODUCE THESE NEMATODE IN INFECTED HOSTS.... ONE
INFECTED HOST CAN PRODUCE MILLIONS OF NEMATODES.
I would think either the costs of rearing the parasites or
isolating a significant number would make the price staggering.
THE DEVELOPMENT OF THE REARING TECHNIQUES HAVE TAKEN YEARS, AND YES,
IT IS AN EXPENSIVE AND RISKY PROCESS
4. I regularly work organic matter into my beds, and as such, have
many large white grubs ("June Beetle") in all my beds and lawn (which
never seem to cause any problems). My question is, how could such a
large natural population of grubs be present without any parasitic
nematodes being present as well. (I'm sure that some parasitic
nematodes are found in my soils at this point.) What difference
could the addition of a small amount of nematodes have upon an
already active, healthy "soil environment?"
IN ALL NON-STERILE SOILS THERE ARE NATURALLY OCCURING INSECT
PARASITIC NEMATODES... WHEN ONE APPLYS A COMMERCIAL PRODUCT, ONE IS
ARTIFICALLY INCREASING THE POPULATION... APPLICATION RATES ARE
USUALLY LISTED AS THOUSANDS OR MILLIONS PER GALLON.
HOPE THIS INFORMATION HELPS
Beverly Sparks, Professor
Extension Program Coordinator-Entomology
The University of Georgia
706-542-1765 706-542-3872 fax
bsparks@uga.cc.uga.edu
