Fruit Pest News

Volume 4, No. 7   April 28, 2003

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. Strawberry Anthracnose Found

    3. Blueberries and Brambles: Switch Fungicide Labeled

    4. Apples: Changes to Apogee Label

    5. Apples: "Soft" Products for Disease Control

    6. Vegetable Corner: Sandea Herbicide Registered

    7. Tree Fruit: Pheromone Trap Catches and Biofixes

1. Current Conditions

Not to jinx us or anything, but it appears that, for the fifth consecutive year, most Tennessee peach growers will produce a decent crop. Such a string of crops used to be unheard of, between spring frosts and winter kill. On apples, cedar-apple rust made an early appearance yesterday on Golden Delicious in Nashville. Fungicidal protection from rust is needed through the first cover spray, usually late April to early May. Harvest has begun for plasticulture strawberries, and blackberries are in full bloom. (SB)

2. Strawberry Anthracnose Found

Plasticulture strawberries have begun harvest and anthracnose has appeared. Fruit anthracnose has been confirmed in one case and is suspected in two other reported cases. There is always the chance that infested transplants could be the source of anthracnose found in the field. Be on the lookout for this disease and please let us know if you suspect you have it.

To safeguard against anthracnose, you can follow an alternation program between Quadris and captan, on a 7-10 day schedule. In severe anthracnose cases, Quadris should be applied once per week for 4 weeks during harvest. The Quadris label requires that other labeled fungicides also be used in a Quadris program, to guard against resistance developing. Use a fungicide that has anthracnose activity when rotating away from Quadris.

One strategy would be to make a captan or Switch application between each Quadris application. Captan provides fair control and Switch provides excellent control. However, Switch is limited to 55 oz per acre per year, and some of that allotment may have been used during the bloom period. Switch also has a 12-month plant-back restriction for any crop other than strawberries or onions.

Another strategy in fields in which anthracnose is a problem would be to tank-mix Quadris with captan, but the requirement of alternating to a fungicide not related to Quadris for 1 application after the second application of the tank mix must still be satisfied. (SB)

3. Switch Fungicide Labeled for Blueberries and Brambles

Switch 62.5WG fungicide has been registered for use on bushberries (blueberries, currants, gooseberries, elderberries, huckleberries, and other cultivars and hybrids of these) and on caneberries (blackberries, raspberries, and cultivars and hybrids of these). Switch contains the active ingredients cyprodinil and fludioxonil. The label lists the diseases mummy berry, anthracnose, Alternaria fruit rot, Phomopsis, and Botrytis fruit rot. Most of these diseases apply to blueberries; it remains to be seen what blackberry and raspberry diseases other than Botrytis will be controllable with Switch. Additional research will reveal this.

The rate for bushberries and caneberries is 11-14 oz per acre, with a limit of 56 oz per acre per year. Label indications: Make the first application during early bloom. A second application should be made 7-10 days later. Additional applications can be made at 7-10 day intervals if conditions remain favorable for disease development. Make no more than 2 consecutive applications before using another registered fungicide. The preharvest interval is 0 days. Do not plant any other crop for a period of 12 months after use unless Switch is registered for that use. (SB)

4. Changes to Apogee Label

Apogee is used for both growth control and fire blight shoot blight control in apples. The following article was written by Dr. Rob Crassweller, Pennsylvania State University, for Fruit Times. (SB)

Apogee has been available to Pennsylvania growers for two full growing seasons, and many growers have been learning about the nuances of how to utilize this material for both growth and fire blight control.  BASF has modified and updated the Apogee label.  The first is the change to recommend any non-ionic surfactant instead of a specific brand.  The restriction on tank mixing with calcium has been softened to a warning about potential lower effectiveness of Apogee and a caution was also added about tank mixing with boron materials.  The label also does not restrict subsequent applications to a 10 to 17 day period; rather subsequent applications can be made at 1-4 week intervals before or immediately after shoots show signs of regrowth.  Remember, for growth control the timing of the first application is the most important first step.  The first application should occur when shoot growth is 1-3 inches.  This period in Pennsylvania orchards usually coincides with petal fall.  It is better to apply the material earlier than later.  Apogee may cause cracking of fruit on Empire or Stayman.

5. "Soft" Products for Disease Control in Apples

There are quite a few biological and biorational disease-control products on the market. The following article was written by Dr. Alan Biggs, West Virginia University, for The Orchard Monitor. (SB)

Various mineral and plant oils are known to be effective against powdery mildew. Oils traditionally have been used to combat insect and mite pests as well as to serve as a carrier or adjuvant for copper fungicides. Oils have limited kickback activity, about 24 hours, and their protective activity is very much dependent upon the type of oil used and, not surprisingly, the amount of rainfall. Oils, though, have very little activity against apple scab and most of the other major pathogens of apple, and captan cannot be used in combination with oil sprays.

Potassium bicarbonate (e.g., Armicarb 100, Kaligreen) can be effective if applied regularly and as a protectant. Mono-potassium phosphate (MKP) has been shown to provide good levels of control, particularly when used in alternation with SI fungicides. Serenade biofungicide, a wettable formulation of the bacterium Bacillus subtilis, has provided good activity against powdery mildew in various trials conducted across the US. All of these "softer" products have little activity against apple scab, are easily washed off in rains, and should not be relied upon to control an epidemic of powdery mildew. These products are much more suited for use at the beginning of a season when disease pressure is low.

6. Sandea Herbicide Registered for Some Vegetable Crops

Sandea herbicide has received a federal registration for several vegetable crops, including cucurbits, snap beans, tomatoes, and peppers.  For information on this label, refer to the article written by John Masiunas, University of Illinois, for Illinois Fruit and Vegetable News. Keep in mind that this article was written for Illinois growers, but much of the information is general. (SB)

7. Tree Fruit: Pheromone Trap Catches and Biofixes

The first obliquebanded leafroller was found in the Nashville trap on April 29. Last year the first ones (5) were caught on May 6 and good numbers were caught until mid-June. They picked up again in late August and early September.

In general, the cool nights last week may have kept trap catch numbers down. On April 29, I did catch 12 Oriental fruit moths but did not catch any redbanded leafroller or codling moth in the Nashville traps. No Oriental fruit moth, codling moth, or redbanded leafrollers were caught in Obion County between 4-21 and 4-28, nor were there any in the Putnam County traps between 4-18 and 4-27. (FH)

Nashville (Davidson County) Pheromone Trap Catches for 2003

* Biofix for RBLR in Davidson County estimated as occurring on March 8

Bradley County Pheromone Trap Catches

*Biofix for redbanded leafroller in Bradley County estimated as occurring on March 8
**Biofix for codling moth in Bradley County was April 5 (2 caught)

Putnam County Pheromone Trap Catches

*Biofix for Putnam County estimated as occurring on March 8

Obion County Pheromone Trap Catches

*Biofix for RBLR occurred prior to trap placement, estimated as occurring on March 8
(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, Associate Professor and Extension Entomologist

fahale@ext1.ag.utk.edu

Both authors available at:

615-832-6802

fax 615-781-2568

Plant and Pest Diagnostic Center

5201 Marchant Drive

Nashville, TN 37211