Brock Dolman, Occidental Arts and Ecology in Sonoma
Re the gap in biocontrol of the gwss by wasps every spring:
There is a question as to whether the wasp and the gwss can overwinter here (Sonoma)
The wasp is a parasitoid organism. The adults have to be out and find gwss egg
masses to lay there eggs in. Therefore the first generation (of the year) of sharpshooters
has to be laid before the wasps can parasitize them. Because the gwss lays no
eggs in winter, yet adults can overwinter and then lay their eggs in the spring.
The first generation of gwss have to lay their eggs then those hatch and that
generation lays enough eggs to provide enough biomass for the wasps to increase
You will never have good control in the first generation of a year.
We can talk about biocontrols once we accept the fact that the gwss is here, as
they have done in southern California, but here in Sonoma the Ag. Commissioner
is saying, "We're gonna keep it out of here by all means necessary."
In his discussions with grapegrowers he gets the feeling that some of them are
beginning to see the inevitability -- the gwss is surviving the winters in Sacramento.
It is moving north, it's only a matter of time before it is established here.
But meanwhile forced spraying is being foisted on us.
About Pierce's disease resistance:
There is resistant rootstock, but the "varietal grapes" are grafted
onto the rootstock, and some of the varietals are more resistant than others.
Unfortunately it is the most chi-chi varietals that have the least resistance.
So what you would need to do is get a resistant rootstock and graft onto it a
resistant varietal, and just accept that you can't grow the grapes for Pino Noir,
Re other non-toxic control methods:
Nets that intercept the gwss when they fly could be put up in the vineyards. Kaolin
clay on the vines that acts as a deterrent. For the medfly the released sterile
males, don't know if that's possible with gwss.
Pierce's disease has been around a long time. There are now $10 million per year
losses due to the BLUE GREEN sharpshooter, which has been accepted. Those losses
have been restricted to vineyards adjacent to (within 100 yards of) a riparian
corridor (a stream). So lots of grapegrowers have just decided not to plant grapes
there. But the gwss will spread beyond riparian corridors. In other words, Pierce's
disease could show up anywhere in the vineyard.
But every species is unique. We don't know how it might play out here with the
*** Basic ecology says that you diversify the amount of predators to control an
organism. Any insectivore (birds, lizards, bats) will eat larger insects like
You need to increase the insectivores. The first thing you do to increase them
is DON'T SPRAY PESTICIDES. Also you increase their basic habitat, increase the
health of the soil and increase the health of the plant. Increase the immune-response
capacity of the vine..
*** They have to reform their practices from the get-go: maybe they can't grow
as many acres; maybe they can't put vines everywhere. Not use so much irrigation
because too much water makes a juicier plant, and the more nitrogen fertilizer
the plants get the thinner the cell walls are, which makes them easily pierced.
The result is juicy, succulent, IRRESISTIBLE plants. They would be better off
The problem is that their goal is tonnage, and health, safety, and ecology are
not comparable with the economics. They need to take into account the externalities.
*** FARMING IS AN ACT OF BIOLOGY, NOT AN ACT OF INDUSTRY. These are living, respiring
breathing organisms, not machines. It's not the Ford plant. Their chickens are
coming home to roost -- the gwss is coming home to roost in that monoculture,
which is implicitly unsustainable.
The production of food and fiber has to be related to the ecology. The scale they
use is an anomaly.
RE Alameda's new vineyard plans, ask: What's the impact of the hydrologic function?
When you are changing from forested, meadows, vegetated, land it changes the runoff
velocity. The runoff will carry soil with it. This results in water quality issues.
Increasing the imperviousness of the system, meaning the ability of the land to
absorb water. We are compacting and degrading our watersheds. We are not recharging
the aquifer. Due to aquifer depletion, in the Fresno area land has sunk as much
as 50 feet.
Ask them about (1) Non-point-source pollution and (2) Storm water input. "Have
they considered Pre-development hydrologic function?"
storm water management plans / water agencies / pollution controls
There are ways to design the vineyards to mitigate these factors.