Fruit Pest News

Fruit Pest News

Volume 9, No. 2 March 26, 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. Current Conditions

2. Additions to Vegetable Disease Control Recommendations for 2008

3. Additions to Fruit Disease Control Recommendations for 2008

4. Other Disease Control Product News

5. Early-Season Apple Fungicide Sprays

6. Suggested Strawberry Fungicide Spray Schedule

7. Changes in the Apple Pest Control Recommendations for 2008

8. Newer Chemistry for Caterpillar Control in Vegetables

9. Pheromone Trap Catches

1. Current Conditions

Rains have been plentiful compared with the last two years to this point in the spring. Let's cross our fingers that this trend continues. The northern half of the state had frosts Sunday, and most of the state had frosts on Monday -- a problem for plasticulture strawberry growers, but most fruit crops are still at early stages. Peaches are just beginning to bloom and apples are still at green tip. Only early-blooming blueberry varieties are blooming. We have been spared the heat wave that plagued us last year in the month leading up to the April 9 freeze. The 10-day forecast calls for mild weather with no chance for freezes. (SB)

2. Additions to Vegetable Disease Control Recommendations for 2008

Revus 2.08SC (mandipropamid) recently received its initial registration. An oomycete fungicide. Crops include: the leafy brassicas other than turnips - cabbage, broccoli, brussels sprouts, cauliflower, collards, kale, and mustard - downy mildew control; 1-day PHI. Dry and green onions and related bulb vegetables - downy mildew control; 7-day PHI. Cucurbit crops - downy mildew and Phytophthora blight suppression; 0-day PHI. Lettuce, head and leaf - downy mildew control; 1-day PHI. Spinach - downy mildew (blue mold) control, 1-day PHI. Peppers - suppression of the foliar and fruit phase of Phytophthora blight (applied to foliage); 1-day PHI. Resistance management needed.

Presidio 4SC (fluopicolide) recently received its initial registration. An oomycete fungicide, it targets downy mildew and Phytophthora blight in cucurbit crops (2-day PHI); late blight and Phytophthora blight in pepper, eggplant, and tomato (2-day PHI); downy mildew of leaf and head lettuce (2-day PHI); and white rust of spinach (2-day PHI). Resistance management needed.

Reason 500SC (fenamidone) - has been added to the recommendations for downy mildew control in the leafy brassica greens other than turnips (2-day PHI); spinach (2-day PHI); and pepper (14-day PHI). Reason also provides control of white rust of spinach and suppression of the foliar and fruit phase of Phytophthora blight (applied to foliage). Reason was previously registered for use in other vegetable crops. Resistance management needed.
Decree 50WDG (fenhexamid) was recently labeled for use on greenhouse tomatoes for Botrytis control, 0-day PHI. Fenhexamid is used in small fruit production under the name Elevate. Resistance management needed.
Midas (iodomethane) received a 1-year federal registration last October for use as a soil fumigant on tomatoes and peppers. Is a broad-spectrum fumigant, with activity against fungal and bacterial pathogens, weeds, and nematodes. Chemically related to methyl bromide, but is not an ozone depletor. Must be certified by both the state and Arysta LifeScience (the registrant) to apply. (SB)

3. Additions to Fruit Disease Control Recommendations for 2008

The propiconazole products, Tilt and Orbit have received registrations for use on bushberries and caneberries. The Orbit label is a supplemental label that expires on 12/31/2011, while the Tilt label is permanent. Included are blueberry, gooseberry, blackberry, raspberry and similar crops. Diseases controlled are mummyberry disease, leaf rust and powdery mildew of blueberry, raspberry leaf spot, and Septoria leaf spot of blackberry. Not included on the label are orange rust and other rusts of brambles.

Revus 2.08SC (mandipropamid) recently received its initial registration. It is labeled for control of downy mildew of grapes. A resistance management program is needed, and there is a 14-day PHI..

Presidio 4SC (fluopicolide) recently received its initial registration. It is labeled for control of downy mildew of grapes. A resistance management program is needed, and there is a 21-day PHI..

Midas (iodomethane) received a 1-year federal registration last October for use as a soil fumigant on strawberries, grapes, stone fruits, and tree nuts. Is a broad-spectrum fumigant, with activity against fungal and bacterial pathogens, weeds, and nematodes. Chemically related to methyl bromide, but is not an ozone depletor. Must be certified by both the state and Arysta LifeScience (the registrant) to apply. (SB)

4. Other Disease Control Product News

Adament 50WG is now registered for use on peaches, cherries, and nectarines for control of peach scab, brown rot, and rusty spot. It is a combination of a sterol inhibitor (tebuconazole/Elite) and a strobilurin (trifloxystrobin/Flint). It has a 1-day PHI.
Ridomil Gold EC, a soil-applied mefenoxam product, has been replaced by the registrant, Syngenta, with a water-based formulation, Ridomil Gold SL.
Ridomil Gold Bravo, a wettable powder formulation of mefenoxam and chlorothalonil, is being replaced with Ridomil Gold Bravo SC, a liquid.
Dow AgroSciences is discontinuing the Nova brand of myclobutanil and replacing it with Rally, the western U.S. version of myclobutanil. However, Dow will continue to support Nova and supplies are adequate to last for a couple of years, so it will remain in our recommendations at least for this year.
Revus Top is a combination of the new a.i., mandipropamid (see above), and a sterol inhibitor, difenoconazole, from Syngenta. It is cleared for use on tomatoes and potatoes, but adequate efficacy data to justify inclusion in our recommendations is not available at this time. (SB)

5. Early-Season Apple Fungicide Sprays

Because of last year's drought, there shouldn't be a large overwintering load of scab inoculum - it should be safe to delay the first fungicide application to tight cluster. This will help provide control of primary scab and cedar-apple rust. The 3- to 4-day curative (kickback) activity of the SI fungicides makes them useful at tight cluster in case some scab infections occurred prior to that time. The SI/protectant combination allows you to space the applications 7 to 10 days apart.

There are several different strategies for scheduling scab sprays. The selection of a spray program (what fungicide to use and how often) depends on factors such as other disease organisms present and the ability to obtain good coverage of the trees with the sprays. If cedar-apple rust or powdery mildew are a threat, it is probably best to control scab with a sterol-inhibiting fungicide (Nova, Procure, Indar, or Rubigan), because control of all three diseases would be obtained. Tank mixing with mancozeb, metiram, or captan would improve the protectant ability and discourage the development of resistance to the sterol inhibitor (SI). Do not use captan within 2 weeks of an oil spray.

Where cedar-apple rust or quince rust are problems, mancozeb, metiram, or ziram should be used as the protectant, to be mixed with the SI. The strobilurin fungicides Flint and Sovran can be used in lieu of the SI's, but I recommend reserving these materials for use during the summer. They may only be applied 4 times per year, and they play a more valuable role during the summer than during the spring.

Powdery mildew inoculum may be abundant in blocks in which mildew was active last year, since we did not have the type winter needed to reduce inoculum. If weather conditions are favorable (cool, wet) for mildew, disease pressure could be high on susceptible varieties. Be sure to use an SI on such blocks, beginning at tight cluster to pink.

Note: If rust and mildew are not particular problems, it may be advisable to begin the season with two sprays of Syllit, Vangard, or Scala, rather than an SI. Although, resistance to the SI's in the apple scab fungus has not been confirmed in the Southeast, it can occur, and some growers have experienced problems controlling scab with these materials. Other fungicides can be tank mixed with Syllit, Vangard, or Scala for rust (mancozeb or metiram) or mildew (sulfur or thiophanate methyl) control. (SB)

6. Suggested Strawberry Fungicide Spray Schedule

Below is a recommended spray schedule to follow for springtime disease control in strawberries. The exact design of a spray schedule can vary depending on disease control needs and products available. However, the principles illustrated below should serve as a good general guide for management of the two most common diseases, Botrytis and anthracnose.

Application no. (At (weekly intervals)	Product	Discussion
If anthracnose is not present
1 (early bloom)	Elevate	Botrytis is the primary target. This fungus is known for "getting used to" a fungicide and developing resistance to it. Try to include 3 chemical classes, as in the example, to keep Botrytis off-balance. Scala represents a 4th chemical class for Botrytis control. You can substitute it for any of the three. These materials can be applied in any order.
2	Switch
3	Pristine
4+ (through harvest)	Repeat sequence; program may be relaxed somewhat during harvest
If anthracnose is present
1 - 4+ (prior to harvest)	Follow above schedule during bloom, with captan or thiram included in each application.	The activity of anthracnose, if present, is low during bloom. The use of captan or thiram will provide adequate protection during this time. Thiram and captan are interchangeable because they are equally effective against Botrytis and also against anthracnose. Thiram has an advantage over captan in that thiram has a deer and rabbit repellency property. Thiram does not fit the harvest period because of a 3-day preharvest interval. Captevate® is a premix of captan and Elevate, and may be used in lieu of a tank mix. NOTE: The strobilurins (Quadris, Cabrio, Pristine) are limited to 5 applications per crop, either individually or collectively. For this reason, beware of using the strobilurins during bloom because you don't want to use up part of your allotment before the harvest period, which is a critical time for anthracnose control. The seasonal limit for Switch is 56 oz/A (4-5 applications). Use captan alone if the tank mix partner (Switch or the strobilurins) scheduled for that week has reached its limit.
Harvest period
1	Captan plus either Quadris, Cabrio, or Pristine
2	Captan plus Switch
3+	Repeat harvest sequence

(SB)

7. Changes in the Apple Pest Control Recommendations for 2008

At Green Tip to 1/2 Inch Green spray, the guide added Isomate CM/OFM TT and CheckMate OFM for mating disruption of Oriental fruit moth and codling moth. At Bloom, Isomate CM/OFM TT was added.

At Petal Fall and again at Second Cover and Later Sprays, the fenproximate miticide Fugimite 5EC was replaced by Portal 0.4EC for European red mite. Note that Portal 0.4EC can also be used for the control of leafhoppers.

At Petal Fall, Lannate 90SP was removed for the control of spotted tentiform leafminer whileDimethoate 4EC and Danitol 2.4EC were removed for control of rosy apple aphid.

At First & Second Cover, pyriproxyfen (Esteem 35WP) was removed & spinetoram (Delegate 35WP) was added for codling moth. At Second Cover and Later Sprays, Delegate 35WP was added for Oriental fruit moth, tufted apple bud moth, spotted tentiform leafminer, redbanded leafroller & lesser appleworm. (FH)

8. Newer Chemistry for Caterpillar Control in Vegetables

While most growers are familiar with the pyrethroid insecticides (Mustang Max, Ambush, Pounce, Capture, Baythroid 2, Baythroid XL, Asana XL, Proaxis and Warrior), and older chemistry such as Monitor, Orthene, Lannate, Sevin, and Thionex for caterpillar control, there are various new products that are due our consideration.

Emamectin benzoate (Proclaim 5 WDG) is a semi-synthetic second generation avermectin insecticide with no documented cases of cross-resistance with other insecticide classes. It is in Mode of Action (MOA) group 6, chloride channel activators which interferes with the GABA nerve receptor of insects. It has excellent residual control and is rainfast as soon as the spray dries. While it is a Restricted Use Pesticide, it is a selective insecticide for control of listed lepidopterous caterpillar pests on fruiting vegetables (except cucurbits), leafy vegetables including Brassica (cole crops), and turnip greens (tops, leaves).

Indoxacarb (Avaunt 30 WDG) is in the new oxidiazine class of insecticides. The novel MOA blocks the movement of sodium ions into certain nerve cell ion channels, resulting in paralysis and death of the pest species. Avaunt 30 WDG is a reduced-risk pesticide with minimal impact on beneficial insects and mites. While primarily a larvicide, it also has activity on eggs and adults of many insect pests. This broad-spectrum lepidopteran insecticide also controls other pests including Colorado potato beetle, leafhoppers, and tarnished plant bug.

Methoxyfenozide (Intrepid 2F) is in the MOA group 18 Biopesticide Insect Growth Regulator, Diacythydrazine Class. Feeding typically ceases within hours of ingestion. Within several days, caterpillars undergo an incomplete and developmentally lethal premature molt. There is virtually no effect on any Order of insects or arthropods except Lepidoptera. This conservation of beneficial arthropods makes it an ideal tool for Integrated Pest Management.

Spinosad (SpinTor 2 SC) is in MOA group 5, nicotene acetylcholine receptor agonists (not group 4), Spinosyn Class. It is labeled for control or suppression of lepidopterous caterpillars, leafminers, and thrips. It is labeled for use on asparagus, cole crops, corn, cucurbits, fruiting vegetables, leafy vegetables, leaves of root and tuber and legume vegetables, okra, potatoes and tuberous corm vegetables, succulent and dry beans and peas, and other listed crops. It does not have a significant impact on certain parasitoid insects or the predaceous arthropod complex, other than reducing the target pest species as a food source. (FH)

9. Redbanded Leafroller

While cold weather kept moth activity down, five more redbanded leafroller moths were caught in the pheromone trap in Nashville by March 25. (FH)

The Fruit Pest News URL is: http://web.utk.edu/~extepp/fpn/fpn.htm

Contacts:

Steve Bost, Professor and Extension Plant Pathologist

scbost@utk.edu

Frank Hale, Professor and Extension Entomologist

fahale@utk.edu

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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