Everett Dietrich of Rincon Vitova Insectiary. Mentor
of Kate Burroughs, 80 yrs old, going strong, 50 years in the biocontrol business.
There's been great success with native wasps in the Filmore area over the last
5 years. The parasites very effective, 90+ percent. In the second generation.
The only thing that's really functioning is an egg parasite. Here in the Filmore
area it seemed to spread into coast Santa Paula over to [So---ma-?] toward Oxnard,
it doesn't seem to go toward the coast. Don't know if it's the effect of the parasite
or the climate.
*** Sharpshooter better this year than last and last year better than the year
Temecula is as far inland as is Filmore and it was bad there and not long ago
I heard that they've dropped off dramatically there too.
.. when the number of eggs being laid and the number of overwintering adults is
declining the percent of parasitizing is not as high as in the second generation.
There seems to be 4 or 5 of these parasitizing wasps all through the South and
mimeridae wasps are all egg parasites. They are tiny. A fairly successful insect.
They lay a dozen eggs in each sharpshooter egg mass.
Bio-controls can eradicate in patches. They actually do stamp out and eradicate,
_in patches_. They have then got to migrate to the next food source.
*** With spraying, all they can do is some delay work.
He worked 15 years for UC in the Department of Biological Controls. On aphids.
*** RE the power of the "natural enemy complex" (wasps, birds, spiders,
bats): When a new insect comes in there's an explosion of the natural enemy complex.
It takes a year of two for them to build up in numbers, it has to overcome and
drive down to a new level.
(But the grape guys are still worried about Pierce's disease.)
*** Even at a nursery here that was quarantined, they don't find 'em much anymore.
Even on the oleanders.
[Last week he spent 3 hours looking at avocados, lemons, wild tobacco on a landfill
(unsprayed area) didn't find (much or any?)]
Last year, there was a lemon orchard that was sprayed regularly, had lots of sharpshooters,
could tell from the white residue on the leaves. This year the new leaves don't
have the residue. [I asked him how come if they sprayed -- didn't that kill the
beneficials? He said:] One lemon orchard was sprayed for gwss, but it was surrounded
by thousands of unsprayed acres of citrus orchards, so beneficial wasps were all
around and took care of it.
*** He said, laughing, You can quote me on this, I don't work for the University
anymore!: But with all the money going into this, they're gonna have to justify
what they have done."
He said his market for beneficial insects is with the city people, parks, etc.
Citrus are usually not sprayed, except lemons for export are sprayed once per
year with a miticide for bud mite, which distorts the fruit. The miticide is a
"soft pesticide" which doesn't mess up the beneficials.
He said there are a number of contracts out to grow these parasites, but he hasn't
found any successful way of doing it. It is not cost-effective unless you have
a steady market.
*** If I grow gwss parasites, it will go away by itself and I will have no market.
The other insectiaries [?that are growing the wasps??] have a subsidiary company
that has Pesticide Control Advisors, the find a spot where every insect they grow
can be sold. As long as you have a place to put every insect.
Phil Phillips, the Farm Advisor, used to work for Dietrich. Says there is about
98% parasitism in July and August.
But the first generation ones overwinter as adults and start laying eggs -- the
trees are loaded with eggs. Parasitism comes along very slowly. Then a lot of
adolescents, which means adults all through the spring.
*** Food drives all these systems. "If you have a lot of rabbits, you will
have a lot of foxes."
But now with the emphasis on spraying and money...
We hate to see them spray the citrus because it's under IPM. Then you gotta work
among the residues with your parasites.
In Filmore, it took about 3 years for it to become less of a pest.
The University needs money, so their policy is "Make as big a deal of it
as you can"
About the question of if the wasps are north of SLO County: If they are not there,
it's just because they haven't got there yet. Because beneficial wasps are tiny
and they would have to be carried.
I'd have to bring adults in, put in cages, get them to lay eggs, expose them to
The gwss needs to be on a plant that is really turgid, plants growing rapidly.
You would see them move around in a mass from one area to another. You don't see
*** They'll only successfully eradicate it if it won't live there anyway."
They are still spraying for the medfly (about a $30 million a year program) and
next will be the Mexican fruit fly.
They have never successfully eradicated anything. Don Dahlsten wrote a book about
this. DD depends on good science. But he doesn't like to fight the battle. And
it's not fun to fight the battle in the university.
*** UC used to have a separate department of Biological Control. and a dept. of
Insect Ecology. Now it is all one. They will tell you "We're all IPM".
Now the UC Entomology departments are all run by chemists.
The ones who are there now are better than who they'd be replaced by.
He was in Berkeley right after the War (WWII)
Tell the Ag. Commissioner - You should have one plot where you're introducing
I can tell you that the gwss has not spread from Filmore beyond about 50 miles.
I was using a vacuum insect net on strawberries and only found about 1 a day.
They fly like birds, and when there's a lot of them it's like it's raining [i.e.,
they are hard to miss].
*** If it wasn't for the disease, the sharpshooter would not be a pest.