Fruit Pest News

Fruit Pest News

Volume 7, No. 1 March 15, 2006

A weekly, online newsletter whose goal is to update Extension agents and growers of commercial tree fruit and small fruit crops

on diseases and insects 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. Fruit Spray Guides: Where to Find

3. Revisions to Fruit Disease-Control Recommendations for 2006

4. Revisions to Vegetable Disease-Control Recommendations for 2006

5. How to Use Scala in Strawberry Spray Program

6. Suggested Strawberry Spray Program

1. Current Conditions - Amazing!

The recent 80 degree weather has peaches in full bloom and apples at tight cluster, and it all happened within just a few days from full dormant buds. Plasticulture strawberries are also blooming. It's scary to have all these blooms open in mid-March. Hopefully, our recent trend away from late-spring frosts will continue (knock on wood). No doubt, many growers were caught unaware and missed some early sprays. Apple trees are in need of a scab spray. Frank has been catching redbanded leafrollers at Nashville. (SB)

2. Fruit Spray Guides: Where to Find

Some of the fruit and vegetable spray guides that we commonly use in Tennessee have been revised and are now available.

Small Fruit - The 2006 Southeast regional integrated pest management guides for blueberries, brambles, bunch grapes, muscadines, and strawberries are available at http://www.smallfruits.org/SmallFruitsRegGuide/index.htm . Print copies are not yet available.

The 2006 Southeastern Peach, Nectarine and Plum Pest Management and Culture Guide (regional publication) - A very limited supply of print copies are available at county Extension offices. It is available for downloading from http://entomology.ent.uga.edu/Peach/peach_guide.pdf .

The 2006 Integrated Orchard Management Guide for Commercial Apples in the Southeast (regional publication) - A very limited supply of print copies are available at county Extension offices. It is not yet available for downloading, but soon will be posted on the Georgia site. I will keep you posted.

The 2006 Commercial Vegetable Disease, Insect and Weed Control (University of Tennessee PB 1282) - Production is being delayed. I will notify you when the print and web versions are available.

The home fruit publication, "Disease and Insect Control in Home Fruit Plantings," is available online at http://www.utextension.utk.edu/publications/pbfiles/PB1622.pdf. and print copies are available at county Extension offices. The online version is scheduled to be revised soon, but the print copies will not reflect the revisions until the inventory is depleted and replaced with revised versions.

(SB)

3. Significant Revisions to Fruit Disease-Control Recommendations for 2006

The following registrations and other changes have occurred within the last year and have been made in our recommendations for 2006.

Grapes

Add Quintec 2.08SC, for powdery mildew. Use rate is 3-4 fl oz/A for 7-14 day intervals, 5-6.6 fl oz/A for 14-21 day intervals. Maximum of 33 fl oz/A/season. Maximum of 2 consecutive applications; 14-day preharvest interval.

Peaches

Remove strobilurins (Pristine, Flint) from early-season sprays, but retain the preharvest period sprays. This change was a decision of the editorial staff of the Southeast regional spray guide, out of concern for resistance management, and is not the result of label changes.

Remove ferbam, due to label changes.

Pome fruits

Add Pristine 38WG, for scab, Alternaria blotch, bitter rot, black rot, white rot, Brooks spot, powdery mildew, sooty blotch, flyspeck. Use rate is 14.4-18.5 oz/A, with a maximum of 74 oz/A/season. Maximum of 2 consecutive applications and 4 strobilurin (Pristine, Flint, Sovran) applications per season; 0-day preharvest interval.

Remove ferbam, due to label changes.

(SB)

4. Significant Revisions to Vegetable Disease-Control Recommendations for 2006

Crop	Action	Product	Important Diseases
Bean, dry	add	Quadris Opti	anthracnose, bean rust
Brassicas, head and stem	add	Cabrio	Alternaria leaf spot, downy mildew, powdery mildew
Brassicas, leafy	add	Cabrio	Alternaria leaf spot, Cercospora leaf spot, downy mildew, powdery mildew
Cucurbits (all)	add add add add	Quadris Opti Forum phosphorous acid Previcur Flex	Alternaria leaf spot, anthracnose, downy mildew, gummy stem blight, powdery mildew downy mildew, Phytophthora blight Phytophthora blight downy mildew
Carrot	add	Quadris Opti	Alternaria leaf spot, Cercospora leaf spot
Corn, sweet	add	Quilt	blights, rusts
Cucumber, greenhouse	add	Previcur Flex	Pythium root rot
Eggplant	add add	Acrobat/Forum phosphorous acid	Phytophthora blight Phytophthora blight
Lettuce	delete	Ronilan	bottom rot
Onions	add add	Quadris Opti Forum	Alternaria purple blotch, downy mildew downy mildew
Pea, English	add	Quadris	Ascochyta blight, seedling disease
Pepper	add add add	AgriPhage Forum phosphorous acid	bacterial spot Phytophthora blight Phytophthora blight
Potato	add add	Forum Previcur Flex	late blight late blight
Spinach	add	Cabrio	anthracnose, Cercospora leaf spot, blue mold, white rust
Tomato, field	add add add add	Quadris Opti Forum Previcur Flex phosphorous acid	early blight, late blight, anthracnose, Septoria leaf spot late blight late blight Phytophthora root and stem rot
Tomato, greenhouse	add	Previcur Flex	Pythium root rot

(SB)

5. How to Use Scala in a Strawberry Spray Program

Scala 5SC was registered last year for use in strawberries for control of Botrytis gray mold. This is the only strawberry disease that it has activity against. It is always good to get a registration for new chemistry. Scala is the only strawberry fungicide from mode of action group 9, the anilinopyrimidines, so you don't have to worry about cross-resistance with another fungicide you're using. Scala has translaminar activity (i.e. locally systemic) and has both preventive and curative properties.

Scala is labeled at 18 fl oz/A whn used alone; 9 fl oz/A when tank mixed with another Botrytis fungicide, which would be all of the fungicides in the following table other than Quadris and Cabrio. It is suggested that Scala be used during the critical Botrytis period, which is bloom. Fungicides from three chemistries (mode of action groups) should suffice for a resistance management program. Thus, it is suggested in the table below that Scala could be substituted for Elevate, Switch, or Pristine during bloom. Scala has a maximum use per year of 54 fl oz/A. (SB)

6. Suggested Strawberry 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. (Weekly intervals)

Product

Discussion

If anthracnose is not present

1 (early bloom)

4+ (through harvest)

Elevate

Switch

Pristine

(repeat sequence; program may be relaxed somewhat during harvest)

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. The new fungicide Scala represents a 4th chemical class for Botrytis control. You can substitute it for any of the three.

It does not matter what order these materials are used in.

If anthracnose is present

1 - 4+

Harvest period

Follow above schedule during bloom, with captan or thiram included in each application.

Captan plus either Quadris, Cabrio, or Pristine

Captan plus Switch

(repeat harvest sequence)

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.

(SB)

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

Plant and Pest Diagnostic Center

5201 Marchant Drive

Nashville, TN 37211

Copyright 2005 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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