|
|
Strawberry Plasticulture – September 1,
2003
Situation Report on Diseased Plants
Vol 4, No. 40 September 1, 2003 (1:30 pm)
Further update: I was able to fly up to Buffalo, NY, this past Thursday
(Aug. 28) morning and rent a car to travel over to Simcoe, Canada,
for a 2-day visit that included a review of the runner tip fields of
Ghesquiere Farms as well as their fresh dug plant production fields.
Mitchell Wrenn of Strawberry Hill Inc., and Gregg Gordon, Aaron’s
Creek, also elected to fly up to Canada to get a firsthand understanding
of the problem, as they work through this crisis with their customers
and other nursery suppliers. I have been most
impressed by the cooperative spirit of our nursery plant suppliers
across the industry during this
past week, and through this entire Labor Day weekend they are working
to provide their customers with up-to-the-minute status reports on
remaining plant supplies and options. One large nursery supplier (who
is not experiencing disease problems at this moment), said to me last
week that this current plant situation is, “not good for any
of us.”
I began to receive a number of calls from concerned and anxious
growers even before my return to Raleigh late Friday night.
It is no wonder
that they are anxious as the investment in an acre of strawberry
plasticulture is very high, and after a very disappointing
2003 spring strawberry
crop for most growers, it is no wonder that everyone wants to start
the 2004 season off with anthracnose-free plants. Here is a re-cap
of the events thus far:
A. Anthracnose infected plugs began showing up in NC, VA, and NJ
last week, and all of these plugs were propagated from runner tips
grown
and shipped by Ghesquiere Farms, Ontario, Canada in July and August.
Apparently, the plants that produced these infected tips exhibited
no symptoms of this disease during the summer at Ghesquiere Farms,
according to the farm advisor I spoke with in Canada on Friday. Yet,
we received positive confirmation of anthracnose in several samples
sent to the NC Plant Disease and Insect Clinic by mid-week last week,
and these infected plugs were grown from tips supplied by Ghesquiere
Farms. One of these clinic reports was copied and shared with the
Mr. Ghesquiere and his farm advisor on Friday.
B. In an update sent out by Dr. Louws and myself on August 27 (prior
to my trip to Canada), we advised plug growers who were seeing hot
spots (showing a general unthriftiness, remaining stunted and becoming
slightly discolored compared to neighboring symptomless plants),
to consider an alternative source of plants. At that time, we did
not
have very complete information on the availability of alternative
source strawberry plants, but I have since learned from an email
sent out
by Debby Wechsler (who is assisting in pulling together information
on alternative plant sources) that Ron Cottle, Cottle Strawberry
Nursery, has at this time (the email is dated Sat. Aug 30) only Chandler
bareroot
(fresh dugs) to sell after October 5th, and he does have some Chandler
and Camarosa tips for sale, but not before Sept. 15th. My apologies
to our agents on Wednesday last week for listing at the end of the
advisory some 8 different suppliers when in fact only 2 on this list
have indicated any availability of alternative plants (i.e. alternatives
to Strawberry Hill and Aarons Creek Farms -both supplied by Ghesquiere
Farms, Ontario). The other respondent was Jeff Harzog who said that
he should still have about 16,000 Camarosa and 10,000 Bish plants
and maybe even a few more than that once they are dug and separated.
Debby
Wechsler may have collected additional news of alternative sources
since my trip to Canada?
C. Because alternative sources were likely going to be extremely
scarce (and are), an important decision was made on Tuesday last
week, in
consultation with the interim Department of Horticultural Science
Head, Dr. Sylvia Blankenship, and with the support of John Vollmer,
President,
NCSA, Inc., to support my trip up to Canada to allow me to personally
see the fresh dug plants being grown at Ghesquiere Farms, and to
bring back specimens of these plants to Frank Louws for further laboratory
testing this week. We collected a total of 800 leaf petioles from
800
different mother plants in two separate Chandler fields. Because
the sampling technique being used for detecting anthracnose is so
new,
the University Office of Legal Affairs has issued this notice:
For growers who receive information about the source of plants in
Canada that has anthracnose problems, you would need to qualify the
information
provided with the following points:
1. The strawberry specialist inspected fields that are of concern
to inspect for proper disease management practices and visual signs
of
the disease. A representative sample of plants was obtained upon
which laboratory examinations were conducted to determine if the
disease
was possible.
2. By the nature of the disease, it may be hidden at the time of
visual and/or laboratory examination, and thus there is some risk
that the
disease may be present but not detected. Therefore, the risk of a
false negative is relatively high.
3. We have done the in-field and laboratory screening to help reduce
the risk to growers, but because the risk of false negatives is relatively
high, the grower assumes risk for any disease that develops subsequent
to the screening.
4. Therefore,our screening process in no way states or implies that
plants are free from disease or the risk of developing disease.
This information should be provided IN WRITING to any grower who
receives information regarding plants from the farm or farms of concern.
from: The University Office of Legal Affairs (Aug. 29, 2003)
D. I wish to reiterate that we have done the in-field sampling in
Canada (Aug. 29) and Frank Louws will soon be doing the laboratory
screening
of these samples, but we are still not going to be in a position
to state that these plants are free from diseases or the risk of
developing
disease as there is a real possibility of getting a “false negative.” Meaning,
that despite very systematic sampling across two large symptomless
Chandler fields (400 samples taken in each), we still may not have
a large enough sample to detect the disease. Hopefully, if there
is a problem in either field, it will be detected in these petioles,
and
we will relate this information asap. Everyone needs to appreciate
that what we are doing is experimental and we will not be able to
state or imply that these plants are free from disease, even if the
samples
are found to be negative.
E. The three main reasons for so much interest in this fresh dug
plant material at Ghesquiere Farms in Canada at his moment are:
-1. The supply of alternative source plants is minimal at best, and
for growers in more northern areas (NJ, MD, OH) who need plant in
the 1-2 weeks, I am not aware of any available disease-free tips
or plugs
that would be ready in time.
-2. The situation with the tips and plugs from this source (Ghesquiere)
has deteriorated further since our departure for Canada on Thursday
(Aug 28). I had this brief note from Buffalo Jct., VA (Aarons Creek
Farms, Inc.) this morning:
“
My viable plugs are going to very minimal at best in the 1st 3 of 5
loads. I might be able to supply a handful of customers willing to
risk planting possibly planting infected plants. Most of the symptomatic
plants now are showing marginal edge burn. Upon close inspection these
plants are randomly exhibiting the petiole lesions also. I had hoped
that I would be able to rogue out hot spots,however, it appears that
in most beds it will be virtually impossible to isolate the good from
the bad at this time.Fresh Dugs are the recommended choice of today.
I had hoped to get back to with better news.” Gregg Gordon,
Aarons Creek
-3. Growers and agents are very interested in knowing what I saw
in Canada. I wish to communicate that I did not see any obvious
anthracnose symptoms in fields walked on Thursday afternoon and
Friday morning.
There were a few wet spots in each field where the plants did not
runner
that well - it has been a very wet summer in Ontario. I was most
pleased with the high vigor and health exhibited by fresh dug Chandler
plants
being grown at Ghesquiere Farms from a Canadian stock plant source
which is using micropropagtion.
Figure 1. In the very late afternoon on 8.28.03, I photographed
this very large Camarosa nursery field at Ghesquiere Farms, Simcoe,
Canada.
I was able to walk this field from end to end.
Another reason I remain encouraged that
these fresh dugs may represent a viable option for growers who cannot
locate alternative plant
supplies relates to an observation made in our last advisory
(Wed. Aug 27):
“…
it is quite possible that the potential for anthracnose infection in
a fresh dug field (planted with California stock) is less than in tip
and plug material, or at least that was the experience of last year.
The disease does not seem to show up as easily in fresh dug plants,
and this may be related to the cooler conditions that prevail when
these are dug in late Sept/Oct. in Canada. Tips are cut in the heat
of summer, and then rooted in even warmer greenhouses here in the Southeast
- ideal for anthracnose expression. It would definitely be our preference
for growers to use fresh dug plants that are apparently free of anthracnose
infection vs. attempting to “make a go of it” with infected
plug plants.”
E. Barclay Poling, Small Fruit Specialist
Campus Box 7609
Kilgore Hall - Office 252
NC State University
Raleigh, North Carolina 27695-7609
919.515.1195
919.515.2505 (fax)
919.418.9687 (mobile)
web site:
http://intra.ces.ncsu.edu/depts/hort/berrydoc/
click HERE
to return to strawberry advisories page
|
|
|
