Fruit Pest News
Volume 9, No. 11 June 4, 2008
An 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. Garden Center Plants Still Carry Destructive Disease
2. Tomato Spray Program for Disease Control
3. Matted-Row Strawberry Disease Control After Harvest
4. Coragen: A New Vegetable Insecticide from DuPont
5. Pheromone Trap Catches
1. Garden Center Plants Still Carry Destructive Disease
Tomato and pepper plants at garden centers remain a source of infection for bacterial spot disease. Despite efforts by TDA to gain the cooperation of the offending nursery, infected plants remain for sale at our garden centers. The small, brown spots can become large problems in gardens, and can spread from there to our commercial fields. Bacterial spot is very difficult to control, especially for home gardeners. Frequent sprays of copper are required, with little to show for the effort if conditions are favorable for the disease. It is recommended that you buy tomato or pepper plants only from local greenhouses until this issue is resolved. By buying from chain stores, you are putting at risk not only your garden but also area farms. (SB)
2. Tomato Spray Program for Disease Control
Generally, a spray program of 7 to 10-day intervals is needed for control of diseases in tomatoes, but can be lengthened to 14 days in dry weather.
The strobilurin fungicides, Quadris or Cabrio, provide unmatched control of early blight. They must be alternated with unrelated fungicides. Prior to harvest, your alternation material can be either an EBDC (maneb or mancozeb) or chlorothalonil. The EBDC's are cheaper than chlorothalonil, and they double as a synergist for copper against bacterial diseases.....chlorothalonil does not. However, the 5-day PHI for the EBDC's interferes with the harvest schedule, and a switch to chlorothalonil is necessary during harvest.
The strobilurins are limited to 6 applications per crop, and the Quadris label prohibits its use prior to 21 days after transplanting. With these restrictions in mind, it is suggested that you begin with an EBDC within a week or two after planting. If you expect bacterial disease problems based on history, add a bacterial control product to each application. It is suggested that you use more than one bacterial control product and alternate them in the schedule. Copper, Actigard, and Agri-Phage are the choices. These materials can be omitted if no problems with bacterial diseases are expected. If such problems should appear later, copper and Agri-Phage can be added at that time. Actigard would not be as suitable because of the lead-in time needed before activation of resistance to the disease.
Specialized control products may be needed if unexpected diseases occur, such as late blight, gray mold, or timber rot. These materials can be found in the spray guide. Spray volume should begin at about 20 gallons per acre, increasing as the plants grow, up to about 100 gallons per acre. Drop nozzles should be used, with the number of nozzles depending on plant height. (SB)
3. Matted-Row Strawberry Disease Control After Harvest
Harvest has
wound down, and now it is time to take steps to produce a healthy bed of plants for
next year's crop. Proper renovation is the most important step in producing a vigorous
crop. When new growth emerges after renovation, fungicide applications may be necessary,
especially in rainy weather. Anthracnose is the greatest threat, since this disease
can prevent bed fill and can debilitate established plants. However, the runner
phase of anthracnose, which affects stolons, petioles and crowns, is difficult
to control. Efforts to control anthracnose on these vegetative parts of the
plant, even with effective fungicides such as Quadris and Switch, may lead to disappointing results.
Resistant varieties such as Delmarvel and Bish do not need control measures.
Phomopsis leaf blight and leaf scorch can be problems in hot, rainy weather, whereas common leaf spot is a problem on certain varieties in cool seasons. Below is a summary of the results I have obtained with field trials on the leaf spot diseases.
Summary of Strawberry Foliar Fungicide Trials
Amount of Disease Control
(0=none, *****=excellent)
|
Product |
Leaf Blight |
Leaf Spot |
| Topsin M |
*** |
*** |
| Captan, Thiram |
** |
*** |
| Nova |
**** |
**** |
| Abound |
*** |
**** |
Please note the following:
4. Coragen: A New Vegetable Insecticide from DuPont
This new insecticide, Coragen, contains
the active ingredient rynaxypyr. Coragen is a 1.67 SC formulation which can be applied
via drip chemigation or as a foliar spray. Coragen is a member of the anthranilic
diamide class of insecticides with a novel mode of action acting on insect ryanodine
receptors. After exposure, the insects rapidly stop feeding, become paralyzed and
typically die within 1-3 days. It is optimal to apply this insecticide at egg hatch
or for newly hatched larvae. Coragen is a Group 28 insecticide that should be a
good addition to resistance management programs. Make no more than 2 successive
applications within a 30 day period to the same insect species on a crop. Also,
this insecticide helps to conserve certain beneficial arthropods (parasites and predators).
Coragen can not be used to treat plants in nurseries, plant propagation
houses, or greenhouses by commercial transplant producers on plants being grown for
transplanting. It is not for use in home plantings nor on ornamental plants. It
is labeled for use only in commercial and farm plantings of brassica (cole) leafy
vegetables, cucurbit vegetables, fruiting vegetables, and non-brassica leafy vegetables.
While it is labeled primarily for caterpillar pests, it is also labeled for Colorado
potato beetle on fruiting vegetables and leafminer larvae and silverleaf whitefly
nymphs for several of the listed crops. (FH)
5. Pheromone Trap Catches
and Biofixes (FH)
Nashville (Davidson County) Pheromone Trap Catches for 2008
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 | CL | |
| 3-10 (Put out RBLR trap) | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 3-13 | -- | 2* | -- | -- | -- | -- | -- | -- | -- | -- |
| 3-19 | -- | 5 | -- | -- | -- | -- | -- | -- | -- | -- |
| 3-31 | -- | 7 | -- | -- | -- | -- | -- | -- | -- | -- |
| 4-1 (put out BCW, OFM, CM, VLR, OBLR traps) | ||||||||||
| 4-9 | 0 | 2 | 0 | 0 | -- | 0 | 0 | -- | -- | -- |
| 4-11 (put out AW trap) | 2** | 0 | 0 | 0 | -- | 0 | 0 | -- | -- | -- |
| 4-17 (put out GBM, DBM, CL traps) | 0 | 0 | 0 | 0 | -- | 0 | 0 | -- | 0 | -- |
| 4-18 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-24 | 2 | 0 | 0 | 0 | 3*** | 0 | 0 | 0 | 0 | 0 |
| 4-29 | 2 | 16 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 5-12 | 6 | 0 | 3^ | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-20 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-27 | 1 | 6 | 17 | 0 | 0 | 0 | 0 | 2 | 0 |
0 |
| 6-2 | 2 | 6 | 8 | 0 | 0 | 0 | 0 | 1 | 0 | 2^^ |
* Biofix for RBLR in Davidson County was March 13.
**Biofix for OFM in Davidson
County was April 11.
***Biofix for GBM in Davidson County was April 24.
^Biofix
for OBLR in Davidson County was May 12.
^^Biofix for CL in Davidson County was
June 2.
Bradley County Pheromone Trap Catches for 2008
tufted apple bud
moth (TABM)
| 3-18 (put out OFM trap) | OFM | CM | TABM |
| 4-6 (put out CM trap, TABM) | 0 | -- | -- |
| 4-12 | 0 | 1 | 4 |
| 4-14 | 0 | 0 | 2 |
| 4-19 | 0 | 1 | 0 |
| 4-21 | 0 | 0 | 23 |
| 4-29 | 1 | 5 | 14 |
| 5-5 | 0 | 2 | 5 |
| 5-11 | 0 | 2 | 13 |
| 5-19 | 0 | 1 | 23 |
| 5-26 | 0 | 0 | 8 |
| 6-2 | 0 | 0 | 3 |
Putnam County Pheromone Trap Catches for 2008
| 3-16 (put out RBLR, OBLR, VLR) | OFM | RBLR | OBLR | CM | VLR |
| 3-21 | -- | 12* | 0 | -- | 0 |
| 4-1 | -- | 5 | 0 | -- | 0 |
| 4-9 (put out OFM, CM) | -- | 7 | 0 | -- | 0 |
| 4-13 | 0 | 0 | 0 | 0 | 0 |
| 4-22 | 0 | 9 | 0 | 0 | 0 |
| 4-29 | 0 | 0 | 0 | 0 | 0 |
| 5-4 | 0 | 0 | 0 | 0 | 0 |
| 5-13 | 0 | 0 | 10** | 0 | 0 |
| 5-20 | 0 | 0 | 30 | 0 | 0 |
*Biofix for RBLR in Putnam County estimated as prior to March 21 (trap not out
early enough).
**Biofix for OBLR in Putnam County was May 7.
Obion County
Pheromone Trap Catches for 2008
| OFM | RBLR | OBLR | CM | VLR | |
| 3-22 (RBLR trap put out) | -- | -- | -- | -- | -- |
| 3-28 | -- | 10* | -- | -- | -- |
| 4-7 (other traps put out) | -- | 0 | -- | -- | -- |
| 4-14 | 0 | 0 | 0 | 0 | 0 |
| 4-21 | 2** | 0 | 0 | 0 | 0 |
| 4-28 | 0 | 0 | 0 | 0 | 0 |
| 5-5 | 1 | 0 | 0 | 0 | 0 |
| 5-12 | 2 | 1 | 0 | 0 | 0 |
| 5-19 | 0 | 0 | 3*** | 1 | 0 |
*Biofix for RBLR in Obion County was March 28
**Biofix
for OFM in Obion County was April 21
***Biofix for OBLR for Obion County was
May 19
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
Soil, Plant and Pest Center
5201 Marchant Drive
Nashville, TN 37211
Copyright 2008 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.
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