Fruit Pest News
Volume 8, No. 21 September 5, 2007
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. Too Dry to Fumigate Strawberry Ground?
2. Previcur Flex for Pythium Root Rot Control in Greenhouse Vegetables
3. Comment Period Extended for Soil Fumigants
4. Peach Variety Disease Susceptibility
5. Insect and Mite Control in Vegetables
6. Pheromone Trap Catch Results
1. Too Dry to Fumigate Strawberry Ground?
The persistent drought has created problems for plasticulture strawberry growers, who find the ground too dry to get their crop in. Dry soil prevents ground preparation opportunities and interferes with the activity of soil fumigants. Methyl bromide is a very volatile fumigant that requires some soil moisture to prevent it from escaping too quickly from the beds, reducing its activity against soil organisms. As a result, you will need to either irrigate or wait for a rain if you plan to use this fumigant.
Methyl bromide/chloropicrin* has the shortest plant-back interval of any registered fumigant, 2 weeks. Other fumigants, such as Telone C-35, require a full 3 weeks. Considering that most areas of Tennessee need to plant by late September, there is little time to wait for a rain before preparing the beds and fumigating, if this has not already been done. However, if irrigation is not possible, you have no choice but to wait for a rain.
Assuming you wait and the 2-week plant-back pushes you too late for planting on time, could you dispense with the fumigation? You would gain some time, but it may cost you in yield. The following table shows data from experiments conducted recently by Dr. Barclay Poling and others at North Carolina State University.
|
Season |
Strawberries previous year? |
Check (non-fumigated) yield (lbs/A) |
Yield improvement (lbs/A) |
|
|
Methyl bromide 67:33 |
Midas (iodomethane) |
|||
|
2004-2005 |
no |
22,313 |
5,697 |
4,198 |
|
2005-2006 |
yes |
20,176 |
8,398 |
10,299 |
|
2006-2007 |
yes |
23,005 |
8,510 |
9,025 |
As the table shows, the benefits obtained from fumigating have been pretty impressive at Clayton the last three years. It also shows the benefit of crop rotation -- Fumigation did not result in as much yield improvement in 2004-2005, following crop rotation, as the other two seasons. (Actual yield is influenced by many factors other than crop rotation, so its benefits may not be apparent when comparing yields across years. The amount of yield improvement by fumigation gives a better measure.) Because of differences in locations, fumigation may not result in as much benefit at your location as in the example above. However, it is probably safe to assume that if you are unable to fumigate, more yield loss to soil organisms can be expected in a non-rotated field than in a rotated one. It may be worthwhile to change plans and prepare a different field if it appears that you will not be able to fumigate in time to allow planting on schedule.
* The formulation of methyl bromide/chloropicrin being used this year is a 50:50 mixture. The 67:33 formulation is no longer available as methyl bromide phases out. (SB)
2. Previcur Flex for Control of Pythium Root Rot in Greenhouse Vegetables
As greenhouse vegetable season gets into gear, consider Previcur Flex for control of a major disease problem, Pythium root rot and damping off. Previcur Flex is the only synthetic fungicide cleared for use in controlling this perennial pest in greenhouse tomatoes, leaf lettuce, cucurbits, and pepper.
|
Before transplanting (Preseeding and/or seedling treatment) - Limit of 2 applications per crop |
Rock wool cube saturation: Prepare a 1:1000 stock solution (e.g., 12.8 fl oz product in 100 gal water). Apply as a drench to cubes at 3.4 fl oz to 6.8 fl oz per cube. |
|
|
Seed beds, soil or soilless: In a minimum of 50 gal water/1000 sq ft apply: 32 fl oz product/1000 sq ft at seeding; or 16 fl oz product/1000 sq ft after emergence. |
|
After transplanting - Limit of 4 applications per crop |
Drip system or soil drench: Prepare a 1:1000 stock solution (e.g., 12.8 fl oz product in 100 gal water). For the first 2 weeks after transplanting, apply at 3.4 fl oz stock solution per cube . After 2 weeks, apply at 3.4 to 6.8 fl oz stock solution per cube. Evening applications will reduce leaching or washing of the product from the root zone and may result in improved control. |
Stock solutions should be used within 1 day of mixing. Do not mix with other products. Prevent intense sunlight after application by applying Previcur Flex in the evening. Do not apply Previcur Flex to dry rockwool or other growing media without first pre- wetting with water. Refer to label for further details.
Other controls for Pythium root rot in greenhouse vegetables include the biological products Actinovate, RootShield, and SoilGard. (SB)
3. Comment Period Extended for Soil Fumigants
From EPA's Office of Pesticide Programs:
As part of EPA's ongoing evaluation of soil fumigant pesticides, and in response to further requests from stakeholders, the Agency is extending the public comment period on risk reduction options until November 3, 2007. On May 2, 2007, EPA issued revised human health risk assessments and requested public comment on risk-reduction options for the soil fumigants: methyl bromide, metam sodium, dazomet, and chloropicrin. Another soil fumigant, 1,3-dichloropropene (Telone) is included for comparison purposes, but its reassessment is complete and few if any regulatory changes are anticipated. More information on soil fumigant risk mitigation options, and how to submit comments is available on EPA's Web site at http://www.epa.gov/oppsrrd1/reregistration/soil_fumigants/risk_mitigation.htm
4. Peach Variety Disease Susceptibility
In making your plans for ordering peach varieties for planting this winter, keep in mind their disease susceptibility. Disease resistance has not been extensively incorporated into many peach varieties. The primary disease for which we have good resistance is bacterial spot. However, that is good resistance to have, because chemical controls for b-spot are fairly limited. Refer to the following web site for a list of peach varieties and their resistance to bacterial spot: http://www.caf.wvu.edu/kearneysville/tables/bspotsus.html
(SB)
5. Insect and Mite Control in Vegetables
I recently attended the annual Southeast
Vegetable Extension Workers meeting where we update the Southeastern U.S. Vegetable
Crop Handbook. One area of discussion was the use of pyrethroid insecticides for
mite control. Several new miticides have been labeled in the past few years and
we have good miticide choices for most vegetable crops. Of course, many of the miticides
tend to be somewhat expensive and growers in some situations may want to utilize
the pyrethroid insecticides bifenthrin (Capture 2EC) or fenpropathrin (Danitol 2.4
EC) on labeled crops. The pyrethroid insecticides are generally toxic to many types
of beneficial insects and mites. When these insecticides are used, there is an increased
probability that mite populations will flare up over time. Thus, the best time to
use a pyrethroid is late in the season and close to harvest when mite resurgence
is no longer a concern. These pyrethroids also have relatively short preharvest
intervals (Capture has a PHI of 3 days for crops such as snap beans and cucurbit
crops and Danitol has a 7 day PHI on pumpkins and squash and 3 day PHI on tomatoes).
Kelthane
WP is no longer being made and is being dropped from the recommendations. There
is still a Kelthane 4EC formulation labeled for spider mites on peppers, tomatoes,
squash, beans, and cucumbers but it is not labeled for cantaloupe and watermelon.
Thiamethoxam
(Actara 25 WDG) received an updated label in 2007. Crops added to the label include
leafy Brassica greens; head and stem Brassica; leafy vegetables (except Brassica),
cucurbits; and tomato. Also, eggplant and other fruiting vegetables were added to
pepper that was already on the label. Actara 25 WDG is being added to the recommendations
for aphid and whitefly control on these crops. (FH)
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), cabbage looper (CL)
| OFM | RBLR | OBLR | CM | GBM | VLR | BCW | DBM | AW | CL | |
| 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, CL) | 10 | 1 | 0 | 0 | -- | 0 | 0 | -- | 0 | -- |
| 4-5 | 11 | 0 | 0 | 0 | 4*** | 0 | 0 | 0 | 0 | 0 |
| 4-10 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-17 | 2 | 1 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 |
| 4-23 | 28 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-25 | 8 | 0 | 2**** | 0 | 0 | 0 | 0 | 4^ | 0 | 0 |
| 4-30 | 5 | 0 | 6 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| 5-21 | 3 | 2 | 6 | 0 | 0 | 0 | 0 | 4 | 5 | 5 |
| 5-29 | 6 | 9 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6-4 | 7 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| 6-11 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| 6-19 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6-26 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7-2 | 0+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7-9 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| 7-17 | 23 | 9 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 0 |
| 7-23 | 25 | 9 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7-30 | 34 | 20 | 2 | 0 | 0 | 0 | 0 | 0 | 2 | 0 |
| 8-10 | 33 | 8 | 2 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 8-23 | 16 | 5 | 4 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| 9-4 | 6 | 4 | 4 | 0 | 0 | 0 | 0 | 0 | 3 | 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.
+ Pheromone lure missing
Bradley County
| OFM | CM | |
| 3-26 | 1 | 0 |
Putnam County
| 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 |
| 5-4 | 0 | 1 | 5 | 6 | 2 |
| 5-11 | 0 | 15 | 0 | 0 | 1 |
| 5-25 | 0 | 24 | 0 | 0 | 0 |
| 5-28 | 0 | 15 | 0 | 2 | 0 |
| 6-2 | 0 | 26 | 0 | 0 | 0 |
| 6-4 | 0 | 8 | 0 | 0 | 0 |
| 6-8 | 0 | 0 | 0 | 0 | 0 |
| 6-13 | 3 | 11 | 0 | 0 | 0 |
| 6-15 | 4 | 0 | 0 | 0 | 0 |
| 6-20 | 13 | 25 | 0 | 0 | 0 |
| 6-22 | 5 | 0 | 0 | 0 | 0 |
| 6-25 | 5 | 0 | 0 | 0 | 0 |
| 6-27 | 2 | 3 | 0 | 0 | 0 |
| 7-2 | 7 | 15 | 0 | 0 | 0 |
| 7-6 | 8 | 25 | 0 | 0 | 0 |
| 7-23 | 12 | 47 | 0 | 0 | 0 |
| 7-27 | 8 | 0 | 0 | 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
| 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**** |
| 5-7 | 10 | 0 | 3 | 0 | 2 |
| 5-17 | 11 | 3 | 7 | 1 | 14 |
| 5-21 | 0 | 7 | 1 | 0 | 5 |
| 5-29 | 0 | 5 | 0 | 0 | 0 |
| 6-4 | 2 | 7 | 1 | 0 | 2 |
| 6-11 | 10 | 2 | 0 | 0 | 0 |
| 6-20 | 6 | 0 | 2 | 0 | 3 |
| 6-25 | 2 | 0 | 0 | 0 | 0 |
| 7-2 | 3 | 0 | 0 | 0 | 6 |
| 7-12 | 10 | 0 | 0 | 0 | 3 |
| 7-16 | 3 | 0 | 0 | 0 | 0 |
| 7-23 | 12 | 0 | 0 | 0 | 3 |
| 8-8 | 19 | 0 | 1 | 0 | 5 |
| 8-13 | 9 | 0 | 3 | 0 | 1 |
| 8-20 | 1 | 0 | 0 | 0 | 17 |
| 9-4 | 6 | 0 | 0 | 0 | 12 |
* 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.
(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, 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 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.
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