Fruit
Volume 4, No. 20
An online newsletter whose goal is to update Extension agents and growers of commercial tree fruit and small fruit crops
on diseases and insects in
Text appearing in blue or red can be clicked to link to
other web sites. Be aware that much of the linked information is produced in
other states and may not be applicable to
In This Issue:
1. Strawberry: Anthracnose Alert
2. General: Two New Fungicides from BASF
3. Apple: Cosmetic Storage Diseases
4. Apple: Prevent Storage Decays
5. Insect Updates
6. Pheromone Trap Catches and Biofixes
1. STRAWBERRY ANTHRACNOSE ALERT
Anthracnose began showing up in strawberry plug beds last week in NC, VA,
and NJ, and some TN beds also contain apparently infected plants. The common
source of runner tips for these affected operations is Ghesquire
Farms,
What to do if infected plants are found:
If a source of clean plants can be found, use them. However, it will be
extremely difficult to locate clean plug plants at this time, especially in
light of the current demand for clean plants. Dr. Barclay Poling, NC State University,
traveled to Ghesquire Farms last Thursday and Friday
to assess the situation. He found no anthracnose symptoms in the fields
(anthracnose typically does not appear on runner tips until some time after
planting). His hopes are that Ghesquire's fresh-dug
(bare root) field has promise for anthracnose-free plants, because it was
planted with Canadian, micropropagated plants. The
field from which the apparently-infected tips were taken originated from
So where does that leave you, if you find infected plants in your plug bed? Hopefully, the amount of anthracnose you find is small. If it is found in scattered locations in the bed, remove and destroy (bury) trays of infected plants and 1 to 2 sets of trays surrounding the affected area(s). THIS ROUGING PROCESS MUST BE CONDUCTED EVEN IF YOU FOLLOW A SPRAY PROGRAM. Fungicides only protect healthy tissue -- they do not cure infected plants. Avoid touching healthy plants after handling diseased plants. Minimize overhead watering.
Fungicides may be used in outdoor beds, but not in greenhouses. Keep in mind that fungicide programs reduce disease buildup, they do not eradicate the causal organism, and all it takes is one lesion to produce enough spores to eventually result in an epidemic in the field. With that in mind, you can embark on a spray program if desired. Apply a tank mix of either Quadris or Cabrio with captan, alternated with captan applied alone on a 5 to 7 day schedule. The rates per 2000 square feet are 0.56 fl oz for Quadris, 0.64 oz for Cabrio, and 3.7 oz for Captan 50WP. The strobilurins (Quadris and Cabrio) must be alternated with captan even if they are applied as tank mixes. (SB)
2. Two New Fungicides from BASF
BASF Corporation announces the federal registration of two new fungicides, Endura and Pristine. Labeled crops for Endura include potatoes, lettuce, tomatoes, peppers, eggplant, and beans (dried and succulent). Endura is in a new class of compounds with a new mode of action. The active ingredient is boscalid, and it was developed under the code name BAS 510F. Endura will provide much-needed control of Botrytis and Sclerotinia, as well as several leaf spot diseases, rust, and Rhizoctonia.
Labeled crops for Pristine include stone fruits, tree nuts, grapes, strawberries, blueberries, brambles, onions, and carrots. Pristine is a combination of pyraclostrobin (the active ingredient in Cabrio) and boscalid (the active ingredient in Endura). Pristine was developed under the code name BAS 516F. Despite the double whammy provided by the two active ingredients, resistance management practices are still recommended and provided on the label.
As with any new registration, these products are faced with a couple of
hurdles that must be dealt with before they are adopted: state registration and
availability. By next growing season, Endura and
Pristine should be registered in
3. Cosmetic Apple Storage Diseases
Apple scab, sooty blotch, and flyspeck can develop after harvest, in
storage. Their appearance can reduce the marketability of the fruit. Although these
diseases first appear or increase in storage, they are the result of infections
that took place in the orchard before harvest. These diseases are favored by
wet, mild weather.
Storage
scab is sometimes referred to as 'pinpoint' scab because of its small size,
from barely visible up to 1/8 inch in diameter. The lesions are black and often
shiny because of the intact cuticle. They are circular and differ from scab
lesions that develop in the orchard by a darker color and a definite border.
Late-season scab that becomes visible before harvest closely resembles storage
scab. Late-season scab lesions often remain viable in storage and enlarge by
forming a fringe of olive-green mycelia around the margin of the scab spot.
At optimal temperatures for the scab, sooty blotch, and flyspeck fungi (roughly
62º to 76º F), about 8 to 10 days are required for symptom development after
infection. Symptom development does not occur below 48º F.
Control of these cosmetic storage diseases must take place before harvest; that
is, infection must be prevented on the tree. In selecting fungicides, preharvest intervals for the fungicides in question are a
primary consideration. Then consider what diseases to target. In orchards in
which sooty blotch and flyspeck is active, Benlate, Topsin M,
4. Prevent Apple Storage Decays
The previous article discussed cosmetic apple storage diseases. Other
storage diseases such as blue
mold, caused by Penicillium expansum, and gray mold, caused by Botrytis cinerea, involve decays that actually reduce marketable
yields. Unlike the cosmetic storage diseases, most of the decay disease
infections occur in storage, mostly through wounds. Control tactics differ for
the two types of storage diseases. However, certain late-season fungicide
sprays in the orchard can help reduce both types. Applied at 14 days before
harvest, a tank mix of either Benlate or Topsin M with either captan or ziram helps control storage decays and sooty blotch and
flyspeck. Chemical control after harvest has become extremely limited.
Sanitation practices are more important now than ever.
If you have had problems in the past with storage decays, you are encouraged to
visit http://www.nysaes.cornell.edu/ent/scaffolds/2002/8.19.html#d1
for details on control. The article was written by David Rosenberger,
5. Insect Updates
Grape
Another grape berry moth (GBM) trap was put at a Middle Tennessee commercial
vineyard in
Codling Moth
The codling moth trap at
Oriental Fruit Moth
Moths have been caught most of the summer in fairly high numbers. The
overlapping of generations is especially prevalent this time of year. It is
difficult to determine when the fourth generation egg laying occurs and
continuous egg laying can occur from August through
October. Treat within 7 to 10 days of a pheromone trap threshold of 10 moths
per trap per week. Maintain spray intervals on a 2 week schedule as long as the
threshold is exceeded. Pay particular attention to apple orchards adjacent to
peach orchards this time of year. These apple orchards could see movement of
moths into them because the peach orchards are no longer as attractive to egg laying by the Oriental fruit moths. This shift away from
peaches as the primary host usually occurs after most of the peaches have been
harvested and when the twigs are not as succulent and attractive.
(FH)
6. Pheromone Trap Catches and Biofixes
Nashville (
|
3-17 put out |
OFM |
RBLR |
OBLR |
CM |
GBM |
|
3-18 |
0 |
3* |
0 |
0 |
0 |
|
3-20 |
0 |
18 |
0 |
0 |
0 |
|
3-24 |
0 |
27 |
0 |
0 |
0 |
|
3-31 |
0 |
12 |
0 |
0 |
0 |
|
4-2 |
1 |
5 |
0 |
0 |
0 |
|
4-4 |
2 biofix |
1 |
0 |
0 |
1 not biofix yet |
|
4-7 |
4 |
4 |
0 |
0 |
0 |
|
4-11 |
1 |
5 |
0 |
0 |
0 |
|
4-14 |
4 |
4 |
0 |
0 |
0 |
|
4-21 |
50 |
10 |
0 |
0 |
0 |
|
4-29 |
12 |
0 |
1 |
0 |
0 |
|
5-2 |
17 |
0 |
47 biofix |
0 |
0 |
|
5-5 |
15 |
0 |
40 |
0 |
0 |
|
5-13 |
7 |
2 |
45 |
0 |
0 |
|
5-19 |
7 |
26 |
11 |
0 |
2 |
|
5-27 |
14 |
25 |
7 |
0 |
0 |
|
6-2 |
14 |
49 |
3 |
0 |
0 |
|
6-16 |
13 |
3 |
0 |
0 |
0 |
|
6-23 |
11 |
1 |
0 |
0 |
0 |
|
6-26 |
11 |
0 |
1 |
0 |
0 |
|
7-7 |
26 |
0 |
3 |
0 |
0 |
|
7-14 |
21 |
1 |
1 |
0 |
1 |
|
7-21 |
15 |
1 |
2 |
0 |
1 |
|
8-4 |
29 |
5 |
1 |
0 |
0 |
|
8-12 |
21 |
0 |
0 |
0 |
0 |
|
8-28 |
25 |
3 |
0 |
0 |
0 |
|
9-2 |
21 |
19 |
4 |
0 |
1 |
* Biofix for RBLR in Davidson County estimated as
occurring on March 8
Williamson
County (Nolensville) Grape berry Moth Pheromone Trap Catch
|
|
GBM |
|
7-11 |
5 |
|
7-18 |
11 |
|
7-25 |
5 |
|
8-3 |
5 |
|
8-10 |
0 |
|
8-18 |
1 |
|
8-24 |
3 |
|
|
OFM ( traps) |
RBLR |
CM |
TABM |
|
3-10 |
0 |
22* |
0 |
0 |
|
3-17 |
0 |
69 |
0 |
0 |
|
3-24 |
0 |
19 |
0 |
0 |
|
3-31 |
7 |
18 |
0 |
0 |
|
4-14 |
22 |
28 |
10** |
0 |
|
4-21 |
19 |
5 |
69 |
3 biofix |
*Biofix for redbanded leafroller in
**Biofix for codling moth in
Putnam County Pheromone Trap Catches
|
put out 3-26 |
OFM |
RBLR |
CM |
|
3-31 |
0 |
8* |
0 |
|
4-2 |
0 |
11 |
0 |
|
4-5 |
0 |
17 |
0 |
|
4-7 |
0 |
3 |
2 |
|
4-9 |
2 biofix |
5 |
0 |
|
4-11 |
0 |
5 |
0 |
|
4-18 |
5 |
15 |
0 |
|
4-27 |
0 |
0 |
0 |
|
5-2 |
5 |
1 |
0 |
|
5-12 |
0 |
1 |
0 |
|
5-16 |
0 |
5 |
0 |
|
5-23 |
5 |
24 |
0 |
|
6-2 |
0 |
4 |
0 |
|
6-6 |
0 |
12 |
0 |
|
6-16 |
0 |
1 |
0 |
|
6-27 |
0 |
0 |
0 |
|
7-11 |
0 |
0 |
0 |
*Biofix for
Obion County Pheromone Trap Catches
|
|
OFM |
RBLR |
CM |
|
3-31 |
0 |
2* |
0 |
|
4-8 |
1 |
10 |
0 |
|
4-14 |
2 biofix |
9 |
0 |
|
4-21 |
5 |
27 |
0 |
|
4-28 |
0 |
0 |
0 |
|
5-6 |
0 |
0 |
0 |
|
5-19 |
0 |
0 |
0 |
|
5-26 |
0 |
12 |
0 |
|
6-3 |
0 |
36 |
0 |
|
6-10 |
0 |
24 |
0 |
|
6-18 |
0 |
29 |
0 |
*Biofix for RBLR occurred prior to trap placement,
estimated as occurring on March 8
(FH)
The Fruit Pest News URL is: http://web.utk.edu/~extepp/fpn/fpn.htm
Contacts:
Steve Bost, Professor and Extension Plant Pathologist
Frank Hale, Associate Professor and Extension Entomologist
Both authors available at:
615-832-6802
fax 615-781-2568
Plant and
