Fruit Pest News
Volume 8, No. 8 May 1, 2007
A weekly, online newsletter whose goal is to provide all interested persons with timely information on diseases and insects of commercial fruit and vegetable crops in Tennessee.
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 Tennessee.
In This Issue:
1. Current Conditions
2. New Mustang Max Label Adds Fruit Uses
3. Peaches: Considerations for Disease Control Program
4. Blackberry Anthracnose
5. Fungicide Spray Program for Blackberries
6. Pheromone Trap Catches
1. Current Conditions
Some orchards have some fruit of apple varieties that bloomed after the freeze, and late varieties of blackberry are still blooming. Grapes are pushing out secondary buds, but crops will be greatly reduced. The extent of wood injury to all crops remains to be seen. The weather remains dry, to the delight of strawberry growers, who are in harvest season. Strawberry picking weather has been great. However, the upper 80-degree temps of Monday and Tuesday may have caused some blossom damage on black plastic, where the sun can raise temps into the 90's. There may be a need for some PR work to let the public know that not all fruit crops were lost to the freeze. Customers may just assume that to be the case. (SB)
2. New Mustang Max Label Adds Fruit Uses
Mustang Max is a pyrethroid insecticide,
zeta-cypermethrin, from FMC Corporation. It can now be applied to grapes with a
one day pre-harvest interval (PHI), the berries crop group (blackberry, loganberry,
red and black raspberry, blueberry [highbush and lowbush], currant, elderberry,
gooseberry, huckleberry, and cultivars and/or hybrids of these) with a one day PHI,
the pome fruit group with a 14 day PHI, and the stonefruit group with a 14 day PHI.
Note that the berries crop list does not include strawberries. In addition to the
new label, there is a supplemental label to be used in combination with existing
labels on Mustang Max containers.
Mustang Max, like other pyrethoids, has
activity against a broad range of insect pests. Insects listed on the lablel for
grapes include leafhoppers. The berries crop group lists leafrollers, orange tortrix
and root weevils. On pome fruit, listed pests are apple maggot, codling moth, green
fruitworm, Japanese beetle, obliquebanded leafroller, Oriental fruit moth, plum curculio,
redbanded leafroller, stink bugs, tarnished plant bug, tufted apple bud moth, white
apple leafrollers, and several other pests. On stone fruit, there is an extensive
list of insects including American plum borer, peach tree borer, lesser peachtree
borer, peach twig borer, green fruitworm, leafrollers, leafhoppers, plum curculio,
Oriental fruit moth and several others. (FH)
3. Considerations for Spraying Peaches for Disease Control
There aren't many diseases that threaten the leaves of peaches and nectarines, so an intensive spray schedule is not needed in a no-fruit orchard. In varieties highly susceptible to bacterial spot, Mycoshield or captan/Syllit should be sprayed every couple of weeks until mid-summer. In all varieties, occasional fungicide applications may be in order. Peach scab will build up on unsprayed twigs and result in increased inoculum pressure next year. Brown rot inoculum should not build up unless there are some surviving fruit left attached to the trees, as they will become infected as they ripen. From the fruit, the fungus can move into the twigs and produce cankers that can serve as sites for perrenial (Valsa) canker. Sulfur will control brown rot, peach scab, and powdery mildew inexpensively and is probably the best choice for disease control in no-fruit orchards. One application per month may be adequate. Where only a few fruit remain, it may be worthwhile to remove them, so that they do not serve as targets for brown rot. (SB)
4. Blackberry Anthracnose
Anthracnose is characterized by dull brown, scabby, flattened, cracked drupelets on blackberry fruit. On ripe berries, recently-infected drupelets show a light purple discoloration. Leaf lesions are small, purple spots with white to tan centers. Spores produced by these spots can splash to the berries and produce the scabby berry condition. The fungus overwinters on leaf and berry debris and on canes.
I have found in my research trials with Benlate that control of blackberry anthracnose was best when applications were made at early bloom and at two-week intervals for two additional applications. In plantings with a history of anthracnose, this protectant schedule is recommended, using captan and a strobilurin (Pristine, Abound, or Cabrio). More frequent applications may be needed in excessively rainy weather. Do not apply a strobilurin more than twice consecutively before switching to captan. After harvest, floricanes should be removed and destroyed, to reduce the amount of carryover inoculum. (SB)
5. Fungicide Spray Program for Blackberries
Our blackberry fungicide recommendations are provided in the regional spray guide. I am providing a simplified program, below, for those who may need some help in designing a program.
The rosette (double blossom) schedule is based on research conducted by Dr. Barbara Smith, USDA-ARS, who has found that Pristine and Switch are among the most effective labeled fungicides for rosette control. Primocanes need protection in rosette fields as long as infected blooms are open, which can last from the bloom period until after harvest ends. Remember that the benefits of a rosette spray program will not be seen until the following spring, when this year's primocanes come out of dormancy.
Rates can be obtained from the regional sprya guide or the product labels. Always read and follow label directions.
|
Application number (Applied every 10-14 days) |
If rosette disease is expected |
If anthracnose is expected, but not rosette |
|
1 (early bloom) |
Pristine |
Captan |
|
2 |
Switch |
Pristine |
|
3 |
Pristine |
Captan |
|
4 |
Switch |
Pristine |
|
5 |
Pristine |
Captan |
|
6 (harvest begins) |
Switch |
Pristine |
|
7 |
Pristine |
Elevate or Switch |
|
8 |
Switch |
Pristine |
|
9+ (after harvest) |
* |
* |
|
* Pristine and Switch are limited to 4 applications per year -- If rosette blooms are still present after harvest, fixed copper or Bordeaux mixture can be used, but can cause plant damage in hot weather. For anthracnose control after harvest, Captan can be used (limitation of 5 applications per year). For cane and leaf rust control, Nova can be used. Abound or Cabrio can be substituted for Pristine, but are not as effective against Botrytis. Captan is not recommended for use during harvest because of a 3-day preharvest interval. (SB) |
6. Pheromone Trap Catches for 2007
Nashville (Davidson
County)
Oriental fruit moth (OFM), redbanded leafroller
(RBLR), obliquebanded leafroller (OBLR), codling moth (CM), grape berry moth (GBM),
variegated leafroller (VLR), black cutworm (BCW), diamondback moth (DBM), armyworm
(AW)
| OFM | RBLR | OBLR | CM | GBM | VLR | BCW | DBM | AW | |
| 2-22 (caught one RBLR in last year's trap) put out new trap | -- | 1 | -- | -- | -- | -- | -- | -- | -- |
| 2-26 | -- | 0 | -- | -- | -- | -- | -- | -- | -- |
| 2-28 | -- | 1* | -- | -- | -- | 1 | -- | -- | -- |
| 3-2 | -- | 3 | -- | -- | -- | 0 | -- | -- | -- |
| 3-12 | -- | 50 | 0 | -- | -- | 0 | -- | -- | -- |
| 3-14 (Put out OFM, CM, OBLR, BCW) | -- | 26 | -- | -- | -- | 0 | -- | -- | -- |
| 3-20 | 0 | 33 | 0 | 0 | -- | 0 | 0 | -- | -- |
| 3-21 | 1 | 7 | 0 | -- | -- | 0 | 0 | -- | -- |
| 3-26 | 20** | 34 | 0 | -- | -- | 0 | 0 | -- | -- |
| 3-27 (put out AW trap) | 8 | 4 | 0 | 0 | -- | 0 | 0 | -- | -- |
| 3-30 | 12 | 16 | 0 | 0 | -- | 0 | 0 | -- | 0 |
| 4-2 | 18 | 18 | 0 | 0 | -- | 0 | 0 | -- | 1 |
| 4-3 (put out DBM, GBM) | 10 | 1 | 0 | 0 | -- | 0 | 0 | -- | 0 |
| 4-5 | 11 | 0 | 0 | 0 | 4*** | 0 | 0 | 0 | 0 |
| 4-10 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-17 | 2 | 1 | 0 | 0 | 2 | 0 | 0 | 0 | 0 |
| 4-23 | 28 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-25 | 8 | 0 | 2**** | 0 | 0 | 0 | 0 | 4^ | 0 |
| 4-30 | 5 | 0 | 6 | 0 | 0 | 0 | 0 | 1 | 0 |
* Biofix for RBLR in Davidson County was February 28.
** Biofix for OFM in
Davidson County was March 26.
*** Biofix for GBM in Davidson County was April
10.
**** Biofix for OBLR in Davidson County was April 25.
^ Biofix for DBM
in Davidson County was April 25.
Bradley County Pheromone Trap Catches for
2007
| OFM | CM | |
| 3-26 | 1 | 0 |
Putnam County Pheromone Trap Catches for 2007
| OFM | RBLR | OBLR | CM | VLR | |
| 3-19 | 1 | 9* | 0 | 4*** | 0 |
| 3-21 | 1** | 3 | 0 | 2 | 0 |
| 3-23 | 2 | 6 | 0 | 1 | 0 |
| 3-26 | 2 | 15 | 0 | 2 | 0 |
| 3-28 | 4 | 7 | 0 | 1 | 0 |
| 3-30 | 2 | 14 | 0 | 0 | 1 |
| 4-2 | 6 | 32 | 0 | 0 | 0 |
| 4-6 | 2 | 28 | 1 | 1 | 0 |
| 4-13 | 0 | 2 | 1 | 0 | 0 |
| 4-20 | 0 | 7 | 0 | 0 | 0 |
| 4-23 | 0 | 1 | 1 | 2 | 1 |
| 4-25 | 0 | 0 | 1**** | 0 | 0 |
| 4-27 | 0 | 1 | 3 | 0 | 0 |
*Biofix for RBLR in Putnam County estimated as March 2 (trap not out early enough).
**Biofix
for OFM in Putnam County March 21.
***Waiting to verify biofix for CM, many unknown
moths being caught in these traps that can easily be mistaken for CM.
**** Biofix
for OBLR in Putnam County for OBLR was April 25.
Obion County Pheromone Trap
Catches for 2007
| OFM | RBLR | OBLR | CM | VLR | |
| 3-19 | 0 | 17* | 0 | 0 | 0 |
| 3-26 | 5** | 89 | 0 | 1 | 0 |
| 4-11 | 0 | 0 | 0 | 0 | 0 |
| 4-16 | 2 | 0 | 0 | 0 | 0 |
| 4-23 | 0 | 0 | 0 | 0 | 1 |
| 4-30 | 7 | 0 | 10*** | 0 | 17**** |
* Biofix for RBLR in Obion County estimated to be on March 2 (trap not out early
enough).
** Biofix for OFM in Obion County on March 26.
*** Biofix for OBLR
in Obion County on April 30.
**** Biofix for VLR in Obion County on April 30.
The Fruit Pest News URL is: http://web.utk.edu/~extepp/fpn/fpn.htm
Contacts:
Steve Bost, Professor and Extension Plant Pathologist
Frank Hale, Professor and Extension Entomologist
Both authors available at:
615-832-6802
fax 615-781-2568
Plant and Pest Diagnostic Center
5201 Marchant Drive
Nashville, TN 37211
Copyright 2007 The University of Tennessee. All rights reserved. This document may be reproduced and distributed for nonprofit educational purposes provided that credit is given to University of Tennessee Extension.
Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development. University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.