Illinois Fruit and Vegetable News:

A Newsletter for Commercial Growers of Fruit and Vegetable Crops
A Publication of University of Illinois Extension and the College of Agricultural, Consumer, and Environmental Sciences

Vol. 9, No. 2, March 21, 2003

"We are what we repeatedly do. Excellence, then, is not an act, but a habit." --Aristotle

Address any questions or comments regarding this newsletter to the individual authors listed after each article or to its editor, Rick Weinzierl, 217-333-6651, weinzier@uiuc.edu. To receive email notification of new postings of this newsletter, call or write the same number or address.

This issue's words of wisdom ... which usually means the jokes ... are at the end of newsletter ... check the last page.

In This Issue:

Crop Reports (Notes from southern and northern Illinois)

Notes from Chris Doll (phenology updates, fertilizers, San Jose scale, and boron)

New Registrations (New labeling for Cabrio and Procure fungicides and Warrior insecticide)

Fruit Production and Pest Management (Anthracnose of brambles, apple scab, and dormant oil applications)

Vegetable Production and Pest Management (A cold winter for corn flea beetles)

University of Illinois Extension Specialists in Fruit & Vegetable Production & Pest Management

Crop Reports

In the south and southwest, the first obvious signs of green coincided with the first day of spring. Fall planted covers and cereals have initiated growth with the recent rains and increased temperatures, making them quite noticeable against the otherwise drab landscape. Most fields in the region received rain recently and are too wet to be worked, but many other activities have begun. Row covers have been pulled from many plasticulture strawberries, and will go on and off until the danger of frost is past. Pruning of fruit trees continues, with most having finished apples and moving on to peaches. Buds look good on peach, and in most cases there's only a low percentage of winter kill.

Elizabeth Wahle (618-692-9434; wahle@uiuc.edu)

In northern Illinois, day temperatures have been ranging between the mid 40s and lower 50s, with night temperatures in lower 30s. The region received about 0.7 inches of rainfall this month. Dormant season spray program and pruning of grapes and tree fruits are still going on, but otherwise, outdoor farm activities still await more favorable conditions.

Maurice Ogutu (708-352-0109; ogutum@mail.aces.uiuc.edu)

Notes from Chris Doll

Phenology Update: A week of warm weather has started sap flow and visible growth characters. At Edwardsville, apples and pears are pushing towards green tip (on the early varieties), while peaches, apricot, Japanese plum, and sweet cherry are in the swollen bud stage, most brambles have pushed out to ½ inch green, and grapes are still quiet. Rainfall in the past 10 days has totaled 1.4 inches, and we are quite a bit below normal for the year. Some hail in the storm on the 20th caused concern, but no damage that I could see. The most unusual thing of this spring (to date) is the number of relatively calm days, which should make for good spraying conditions. Experience says that the winds will pick up when more sprays need to be applied.

Crops and Activities. With the advancing growth of the fruit buds, the crop potential is easier to see. I am optimistic about both tree fruit and small fruit at this time. Copper sprays for fireblight have been applied and the rest will follow with a few more days of warm temperatures. Pruning continues in many orchards, and I hope that fireblight-susceptible varieties are finished ahead of the sap flow. For peach, it is a good time to proceed as the pruning wounds heal faster and the wounds may be covered with a fungicide spray to prevent canker problems.

It is getting late for fertilizer applications in this area, but the April showers that are due should aid in incorporation in the soil. Once again, the reminder is that a 400-bushel crop of apples removes about 20 pounds of N, 7 pounds of P, and 30 pounds of K, without consideration for the wood removed as prunings. The 250-bushel peach crop that is about average removes 30 pounds of N, 15 pounds of P and 55 pounds of K. Applying nitrogen to apples at bloom or later is not suggested except in cases of deficiency. With peaches, the half rate of nitrogen should be on now and the remainder can be applied after bloom.

Miscellaneous Notes:

Boron levels of most of the leaf samples of strawberries and apples I had tested in the last couple of years have been low. Solubor is suggested in the Spray Guide for use at Pink and Petal fall. Leaf analysis of strawberries can indicate the need for use on that crop.

San Jose scale has been mentioned as an increasing pest in apple and peach. A phone call while writing this report informed me that an apple orchard that has been neglected for 6-8 years is covered with the pest. I have seen dieback of apple shoots from scale, weakening of peach trees, and death of plums and currants. Watch for heavily infested areas when pruning.

Troubles in the strawberry patch abound, as my free straw mulch appears to have missed going through the combine. I have never seen as much volunteer wheat in my life, so Poast usage is forthcoming. The plasticulture growers have missed this problem, but have learned that escaped chickweed grows as well as strawberry plants under the floating row covers.

Chris Doll

New Registrations

New Fungicides for Fruit Crops
Pyraclostrobin (Cabrio 20 EG), a strobilurin fungicide, is manufactured by BASF. This fungicide has been registered for use on several crops including blackberry, blueberry, caneberry, raspberry, and cherry (sweet and tart). The Cabrio 20 EG label is available at: http://www.cdms.net/manuf/1prod.asp?pd=6224&lc=0

Triflumizole (Procure 50WP), from Uniroyal Chemical Company, Inc., has received registration for the use on cherries (sweet and tart). This fungicide is effective for control of powdery mildew, blossom blight and fruit rot (Monilinia species), and leaf spot (Blumeriella jaapii). The Procure 50 WP label is available at: http://www.cdms.net/manuf/1prod.asp?pd=786&lc=0

M. Babadoost (217-333-1523, babadoos@uiuc.edu)

Warrior Label Expanded
The label for the insecticide Warrior (lambda-cyhalothrin), manufactured by Syngenta, has been expanded to allow application to beans, peas, peppers, and eggplant. The new label also allows application to pome fruits (apples and pears), stone fruits (peaches, plums, nectarines, apricots, and cherries).

Rick Weinzierl (217-333-6651; weinzier@uiuc.edu)

Fruit Production and Pest Management

Brambles Anthracnose. To control anthracnose on brambles, a delay dormant spray is needed. This is a critical spray. Liquid lime-sulfur at 20 gallons per acre should be applied when new shoots are ¼ to ¾ inches long. The spray may burn the leaves if applied after new shoots are ¾-inch long. For more information, consult the "Midwest Commercial Small Fruit and Grape Spray Guide, 2003." Also, detailed information on anthracnose of brambles can be found at the website:

http://www.ag.uiuc.edu/%7Evista/abstracts/a700.html

Apple Scab. Early season spray for control of apple scab is essential. The first spray must be applied at green tip. Primary scab spores are mature and disseminated at early bloom. In 2002, some unprecedented apple scab occurred in Illinois. There are several fungicides (Nova, Sovran, Flint, and others) that effectively control apple scab. For more information on control of apple scab, consult the "Illinois Commercial Tree Fruit Spray Guide, 2003." Also, more information on apple scab is available at the following websites:

http://www.ag.uiuc.edu/%7Evista/abstracts/a803.html

http://extension.usu.edu/plantpath/fruit_diseases/fd_apple_scab.htm

http://www.ipm.ucdavis.edu/PMG/r4100411.html

M. Babadoost (217-333-1523, babadoos@uiuc.edu)

Dormant Oil for San Jose Scale and Eggs of Rosy Apple Aphid and European Red Mite

The heading pretty much says it all ... prebloom oil sprays give multiple benefits in terms of insect and mite control. Good coverage suffocates the scales and the eggs of rosy apple aphid and European red mite, and yes, you can apply oil more than once between green tip and pink if time allows. Concentrations of 2 percent by volume are recommended at green tip; dropping to 1 percent by pink reduces any chance of phytotoxicity.

Rick Weinzierl (217-333-6651; weinzier@uiuc.edu)

Vegetable Production and Pest Management

A Cold Winter for Corn Flea Beetles

Following a hot and dry summer with lots of corn flea beetles, cold temperatures descended on Illinois this past winter. As a result, flea beetle survival and the threat of early season Stewart's wilt is expected to be low in much of the state. Erwinia stewartii, the bacterium that causes Stewart's wilt, survives the winter in the gut of the corn flea beetle. Survival of the corn flea beetle is dependent on winter temperatures. Using the average temperature of December, January, and February, the potential for Stewart's wilt can be predicted.

Stewart's wilt is spread in the spring as corn flea beetles feed on and infect seedling corn plants. The bacterium can spread systemically throughout the plant. There are two phases of Stewart's wilt: the seedling wilt phase and the leaf blight phase. The seedling wilt stage occurs when seedlings become infected at or before the V5 stage. The growing point is easily infected; eventually the seedling wilts and dies. Infections of older plants usually result in the development of the leaf blight phase of Stewart's wilt. This phase is characterized by long, yellow to chlorotic streaks with wavy margins along the leaves. Although most commercial field corn hybrids are resistant to Stewart's wilt, the disease is still a concern for susceptible seed corn inbreds and susceptible sweet corn hybrids.

Based on the recent winter temperatures from the Midwestern Climate Center, estimates of early season Stewart's wilt are shown below. Little flea beetle activity is expected throughout much of Illinois. As is typical, a mild winter in southern Illinois has set the stage for the threat of Stewart's wilt there. More on Stewart's wilt in upcoming issues.

Kelly Cook (217-333-6651; kcook8@uiuc.edu; Rick Weinzierl (217-333-6651; weinzier@uiuc.edu)

This issue's "Words of Wisdom"... on small towns ...

•  A small town is a place where nothing happens every minute.
•  Another reason it's harder to get rich in a small town is that everyone is watching.
•  Although everyone in a small town knows what everyone else is doing, they still read the local newspaper to find out who got caught.
•  A small town is a place where you can get a week's rest in half the time.
•  A home town is a place where they'll always wonder how ever got as far as you did.

University of Illinois Extension Specialists in Fruit and Vegetable Production & Pest Management

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