Andrew Landers has done work with hollow cone nozzles and I am
copying him on this reply in case he would like to provide
information to this list-serve group.
As a plant pathologist, my perspective is that "identifying a more
accurate measure of minimum dose requirements for individual
orchards" is about as likely as finding a pot of gold at the end of
the next rainbow. If everyone had identical size trees, pruned them
the same way, and only sprayed when wind speeds were 2-3 mph from the
NW, then we might have a chance of figuring out the optimal nozzling
pattern, travel speed, chemical dosage, etc. Because we can't take
all of those variables out of play, we probably will continue to
over-spray just so that we get minimal-level coverage when spraying
under adverse conditions (e.g., wind, dense canopy, clustered fruit).
That's not to say that we can't make improvements in sprayer design,
calibration, and nozzle selection. It's just that "minimum dose" is
very difficult to define for any given orchard and/or spray condition.
In northeastern United States, we used the SI fungicides for many
years as a "back-stop" for some IPM methods that provided good, but
not always perfect, scab control. One could risk a "minimum dose" of
captan or mancozeb in early-season sprays because the SI fungicides
applied at petal fall and first cover would arrest any scab that
might escape the early sprays. Now many orchards have SI-resistant
apple scab and there is no fall-back position for arresting scab
development if the disease becomes established early in the season.
As a result, growers with SI-resistant scab are almost forced to
over-spray as an insurance policy against scab. A sprayer
perfectly-calibrated to deliver a minimum dose under ideal conditions
could fail miserable if a scab fungicide is essential during a 4-day
period when wind speeds never drop below 15 mph. Even Andrew Landers
hasn't figured out how to engineer the weather!
Con
We have been using this technology for years as a flat fan for
herbicide application. The results have been very good, drift
greatly reduced and pressures reduced. This past season we started
using them on our air blast sprayer to a limited degree. Thus far,
they may be reducing drift, though it is less obvious. If I remember
correctly,Andrew Landers of Cornell has been promoting the use of
these nozzles as a way of reducing drift without compromising
coverage. Maybe someone could forward the question on to him.
You might want to try substituting a couple of nozzles on a side at
a time, and watch results. Water sensitive cards are a good way to
observe results.
It seems as though we have focused on many other tactics for
reducing pesticide usage over the past several years, but are for
the most part using 50+ year old technology. I'd like to see some
work looking at the use of this nozzle technology at lower
pressures, ie, under 100psi and some work identifying a more
accurate measure of minimum dose requirements for individual
orchards, and economical means of adjusting/controlling our sprayers
to deliver that dose. This should not be rocket science, but methods
that are transferable to our operations at reasonable costs.
Mo Tougas
Tougas Family Farm
Northborough,MA
On Feb 20, 2007, at 9:10 AM, Con.Traas wrote:
Hello all,
I am considering trying the new drift-reducing Albuz hollow cone
nozzles (see
<http://www.albuz.saint-gobain.com/anglais/nouveautes.asp>http://www.albuz.saint-gobain.com/anglais/nouveautes.asp),
which are supposed to give far bigger droplet sizes (apparently
each drop is made up of many mini-drops mixed with air bubbles),
which break up into optimal size droplets on impact with plant
foliage. Have any of you used this type of technology for
fungicides (or insecticides) and what do you think of it?
Con Traas
The Apple Farm
Moorstown
Cahir
Co. Tipperary
Ireland
--
**************************************************************
Dave Rosenberger
Professor of Plant Pathology Office: 845-691-7231
Cornell University's Hudson Valley Lab Fax: 845-691-2719
P.O. Box 727, Highland, NY 12528 Cell: 845-594-3060
http://www.nysaes.cornell.edu/pp/faculty/rosenberger/
