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nafex - [NAFEX] Clay and Phosmet vs. Curculio

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  • From: Heron Breen <breen@fedcoseeds.com>
  • To: nafex@lists.ibiblio.org
  • Subject: [NAFEX] Clay and Phosmet vs. Curculio
  • Date: Sat, 11 Jun 2005 21:44:23 -0500

Most of the following are my own unproven observations and thoughts.

Many pioneering orchardists have realised that Phosmet (Imidan) does not need
to be
sprayed in every row of the orchard. The University of New Hampshire did the
replicating studies that finalised the orchardists' conclusions. Plum
Curculio
behave in specific ways. Using degree days and (less effective) scouting,
applying
Imidan at the optimal times of very early emergence through the season
obviously
make sense. But the interesting result is that spraying only the very outside
row
of a block bourdered by Curculio habitat results in only 3% damage throughout
the
block. Spraying the outside 2 to 3 rows results in 1% damage throughout the
block.
I believe block size is based on an acre and up. I thought this was amazing
when I
heard the results of the study a couple years ago, but a career orchardist
said
they'd been doing it for a long time.

Kaolin/Surround. The majority (maybe more than 75%) of Curculio make their
way into
the canopy by crawling. They are not eagar to fly. Only once have I seen one
take
wing. The excessive cleaning that Surround stimulates has little to do with
leaf
coverage or fruit coverage. The brief moments they are laying their eggs on a
slightly dust fruitlet is not going to really deter the buggers. They are
tenacious. It is the trunk, branch, twig and stem journey that really tire
them
out. Folks are caught up on the idea of fruit coverage, but the original idea
was
trunk and branch coatings. This crawling up and down the trunk which the
curcs do
pretty much daily is where all the cleaning up gets to them. If reached, the
grainy
fruit most likely only cements the idea that the tree is not a good candidate
for
laying. If each of us had to spend an extra 2 hours a day cleaning, we might
be
spic and span but we would not get very important stuff done. For insects
with
simple but really important needs daily, this can spell doom or lifecycle
interruption. My point with this is: Surround has been formulated for not
only
spraying equipment but also for full appearing coverage. Studies, which will
most
likely never be done, would probably show that this extremely full coverage
is
mostly decoration. I mean, what chemical manufacturer wants to tell
orchardists
they do not need to apply full coverage? This is the bane of IPM: for years
us
fruit people have all been trained to spray it thick and everywhere. Well, in
this
case, thick is great, but everywhere is not needed, in my opinion. Bottom 1/2
of
the tree, with great coverage of the trunk and branches and internal canopy
and...the ground! The incidental clay coverage in the grass does a very
under-rated
job of keeping Curcs busy. Spraying the orchard floor on purpose may really
deem
effective. Now, the best spraying in my mind is from under the tree and the
periphery of leaves and branches at the circumference of the leaf canopy. To
illustrate this a little further, think about the plant surface when you very
first
apply Surround: there are very few leaves, definitely not a full flush, and
mostly
wood is getting the clay contact. And these early sprayings are the most
important.
The possible downside to Surround is that we may end up selecting for the
strong
flyers among Curculio, and eliminating the crawlers from the gene-pool. I am
not
sure if this gene/behavior selection is possible, but it is food for thought.
In reference to my previous email comments on using other types of clay,
Biodynamic
clay applications for home orchardists (10 trees) can be applied with a paint
brush
from a 5 gallon bucket on a ladder getting as much of the trunk and major
branches
as possible. Kinda like a non-toxic tanglefoot reapplied regularly. Get the
ground
as well. A pulverised/screened potter's clay with water was the original
spray mix
I believe, but just play around with the clays and ratios until you kill your
sprayer if you are the experimenting type. A friend has sort of slop-pump
which
pumps/sprays a thick spray. Good enough.

And the question about which apples are most resistant to Curcs, ie crushing
the
larvae or outgrowing the egg-wound. I noticed some wild trees get deformed
but not
much drop or damage by the Curcs. I saw this was in general related to the
coarseness and density of the flesh, as well as dryness. This observation led
me to
theorise that Russets are less prone to severe Curc injury than other kinds
of
apples. Some grow dense, dry and quick, with the skin rejecting the second
wave of
Curc later in the summer. Maybe the outside of the orchard block or the one
facing
the woods being Russets? Tough skin also seems to be a Curc beater, as some
of my
tough skinned wild beauties never seem to have a crop lessened from curc
damage.
Ok, all above again just from the eyes of a dabbler, so take it all with a
grain of
salt. Thanks for your patience,
Heron Breen
zone 4, Maine







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