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Illinois Fruit and Vegetable News:A Newsletter for Commercial Growers of Fruit and Vegetable Crops Vol. 16, No. 1, April 2, 2010 |
"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. In This Issue:Regional Updates (from Elizabeth Wahle, Maurice Ogutu, and Bill Shoemaker on grapes in northern IL) Notes from Chris Doll (fruit crop development, bees and dandelion control, boron, fireblight control) Fruit Production and Pest Management (crown and cane borers in brambles; prebloom and petal-fall insecticides) University of Illinois Extension Specialists in Fruit & Vegetable Production & Pest Management Upcoming Programs
Regional UpdatesIn the southern region, things are popping. If not for a rather stiff breeze, the last few days could have been deemed perfect -- low 80's, blue sky, fluffy white clouds, and no rain. I have already seen a sea of black plastic laid in preparation for vegetable transplants. Fields are being prepped all over, as evidenced by the number of tractors and anhydrous rigs on the roadways. Based on my fruit plantings (St. Louis Metro East), apricots are in full bloom, peaches are half-inch green to pink, cherries are bud burst to green tip, apples are half-inch green, and pears are at white-bud. Grapes aren't showing any significant bud swell yet, but pruning cuts are "bleeding." Strawberries have been uncovered and are showing good leaf development. Blueberry fruit buds are close to breaking and brambles are showing new primocane and leaf development. The more uncommon fruits such as medlar, shipova, quince, Chinese haw, and azarole are in similar development stages to the more common tree fruit, but che, persimmon, pawpaw, and mayhaw have yet to break bud in my location. The fruiting Cornelian cherry dogwoods are in full bloom. Of the nut crops, pecan and walnut aren't quite to bud break, but the hazelnuts finished flowering last week and the catkins are starting to whither. Primary apple scab control begins at green tip. Remember that captan (or other sulfur containing compounds) should not be used within 14 days of an oil application to avoid phytotoxicity. For complete spray details for scab control and fungicide resistance management, see the 2010 Midwest Tree Fruit Spray Guide http://www.extension.iastate.edu/Publications/PM1282.pdf . Reminder that the best timing for dormant liquid lime sulfur/Sulforix sprays to grapes and blueberries is just prior to bud break -- with the amount of anthracnose and Phomopsis last year, this application is a must in order to reduce inoculum if plants (grapes and blueberries) aren't to bud break yet. Be sure to check the list of upcoming programs at the beginning of this issue. An orchard twilight meeting and a grape growers workshop are coming soon. Elizabeth Wahle (618-692-9434; wahle@illinois.edu) In the northern region, day temperatures have been mostly in the upper 40s to low 60s and night temperatures in the mid 20s to low 40s. It has been extremely warm during the middle of this week, particularly on March 31 and April 1 when the day temperatures were in the upper 70s to low 80s. Some parts of northern Illinois recorded day temperatures above 83°F, which is one of the highest temperature recorded on April 1 during the last 60 years. The area recorded trace amounts of rainfall between March 22 and April 2. Pruning and training of non-bearing trees is still going on in some orchards. Apple leaf bud development is still at dormant, as is leaf bud development in grapes and raspberries. Dormant oil applications are underway in some orchards, and fertilizer and herbicide applications are continuing as well. Growers with greenhouses have started vegetable seedlings indoors that will be ready for transplanting outdoors in May. Maurice Ogutu (708-352-0109; Ogutu@illinois.edu) Budbreak in Northern Illinois Grapes: How are your grapes? If you're in northern Illinois like me, they came through the winter in great condition. However, like my grapes, your grapes just came through a tough previous season. Last year we had enormous disease pressure, very low heat units and low sunlight levels. This likely resulted in lower-than-normal bud quality. The crop potential is partly pre-determined by the quality of the bud developed the previous year. I'm not expecting the best out of my vines this year. But at least we are starting out in good health. And it's nice to have good working weather ... or is it? The recent spell of exceptionally warm weather has grape growers nervous, including me. It's too early to safely enjoy budbreak, but this warm weather is pushing the vines. I was working on young vines in the breeding nursery on Thursday. Some of the young wood at the base of plants was showing bud-swell. They are always early and they can be sacrificed. But the other buds aren't far along. We need the temperatures to moderate, get cool, stay cool for a couple of weeks. Early budbreak means early shoot growth and subsequent risk of freeze on the tender shoots. IF that happens, the vines will push secondary or even tertiary buds. What does that mean? Grapes have compound buds, which means that within each bud are multiple buds, usually 3. These are called primary, secondary and tertiary. They are named so because the primary is the strongest, most productive bud and it emerges first if the compound bud is healthy and fully viable. If the primary bud is not viable, the secondary bud will emerge. These are smaller and generally less productive. If neither the primary bud nor the secondary bud are healthy, the tertiary bud will emerge. Tertiary buds are unproductive on most varieties. Grapes are resilient because of this feature of compound buds. If weather damages the buds, the grapes have a back-up. In the event of a spring freeze damaging shoots, the compound bud will produce a back-up shoot. This is usually the secondary. If this happens, the crop will be smaller, and clusters will be smaller. This can be exacerbated by the previous season if growing conditions were poor. They were poor in northern Illinois last year, so if we lose our primaries, the crop will probably be half of a normal crop, more-or-less. This will depend on the variety, the management quality in the previous season, and the particular challenges of the specific vineyard. In the end, it should lower expectations of the vineyard. And we need to be careful not to push the vines too hard this year. Be mindful of pruning weights and what they mean for the vine. Mine are pretty low this year, so I need to keep my crop loads down. I want these vines to be productive long into the future. I need to make sure the vine builds its strength this year. For now, growers should plan on a modest crop. But it may be a spring where we face different challenges. Be prepared! Bill Shoemaker (630-584-7254; wshoemak@illinois.edu) Notes from Chris DollSpring is springing or has sprung this week. A couple of warm days will be followed with a couple of warmer days into the 80's, so that major growth changes are occurring rapidly. As of Wednesday morning, apricots are near full bloom, peaches at half-inch green, apples at tight cluster, plums at green cluster, brambles at 1/2 to 3/4 inch green, and strawberries are showing new growth after straw was pulled last Saturday. Soil conditions remain very wet following last weekend's rain, but the month's total is only 2.0 inches. Crop potential of all the above fruits looks good, based on flower bud development. Some loss from freezing was noted on thornless and Prime Jim blackberries, a few red raspberry varieties, and a couple of peach varieties. Pruning at this time makes it easy to judge the extent of pruning needed on these crops. I was late in pruning and tying thornless blackberries and learned how easily new bud growth breaks off. The same is true for grape buds that have developed. There has been some publicity about bee losses this winter, and for the first time, my hive was killed. A report from a Missouri fruit grower indicated a 75 percent loss of bee colonies too. Check with your bee man about availability this spring. This might be a year that reducing the competition of dandelion bloom with apples might be more important, and if the dandelion spray was not applied last fall, there is a little time to do it now, if the orchard floor is cleaned of prunings, etc. Amine 2,4-D can be used at 1 quart per acre, and should be applied before pink As apple blossom time approaches, you will note that boron at 2.0 pounds of Solubor per acre is suggested at pink to strengthen the flower, and also at petal fall. If blossom sprays are needed, it can be added then also. Also in the pink spray, feed-grade urea at 3 pounds per acre can be added to foster larger leaves on the fruit spurs. This need varies from orchard to orchard, depending on fertility levels, tree age, and growth. It is a fairly common recommendation that in theory should help leaves injured by frost or freeze, but these leaves may have lost much of the absorptive area to make it most effective. Fireblight was a serious problem in some orchards last year, but I did not see major injury in orchards with a good Apogee program coupled with streptomycin. The first application should be made at full bloom to early petal fall. This timing sometimes develops very rapidly, and it seems to be easy to be late in application. It has only been three years since the disastrous Easter Sunday freeze of April 7, 2007. In sorting through some old records, I found some notes that included words describing the situation as an adversity that was anguishing, calamitous, depressing, desponding, disastrous, distressing, dire, doleful, dreadful, dolurus, and miserable to name a few. I hope that 2010 is much better for the fruit industry. Chris Doll Fruit Production and Pest ManagementCane and crown borers in bramblesWe're nearing the end of the time period when drenching application of Brigade 2EC might be used for raspberry crown borer control in brambles, but it may still be a good time to review the life cycles of this insect and two other common borers in brambles and plan ahead. Raspberry crown borer is a "clear-winged" moth and its larval stage is a caterpillar with fleshy abdominal prolegs that bear hook-like "crochets." It has a 2-year life cycle. Moths fly from August through September and lay their eggs on the undersides of leaves; eggs hatch in September and October and move down the canes to the crown. In their first fall, larvae form a hibernaculum below the soil line, then larvae girdle canes and crowns the next summer before wintering in the roots. They finish development and pupate in the second summer.
Raspberry cane borer is a longhorned beetle; the larval stage is known as a round-headed wood borer. It also has a 2-year life cycle. Beetles feed on canes from June through August, and they lay eggs between rings of punctures on canes. Larvae tunnel to the base of canes by fall. They feed in crowns during their second summer, then pupate the following spring; adults emerge from June through August.
Rednecked cane borer is also a beetle, and the adult stage is known as a metallic wood boring beetle; larvae are called flat-headed wood borers. This insect has 1-year life cycle. Beetles feed on leaf margins from May through August and lay eggs in bark of new growth, usually within 10 inches of the base of canes. Larvae tunnel through canes and reach full size by fall. They pupate in the spring, and adults emerge in May. Damage is characterized by tunnels that spiral around the cane and by symmetrical swellings 1-4 feet above the soil line.
Raspberry crown borer can be controlled by soil-drench applications of Brigade 2EC in October or early November or in March. Biological control by application of insect-pathogenic nematodes (Steinernema feltiae) also is possible. Removing infested crowns is also recommended. To control raspberry cane borer, prune out and destroy infested canes, beginning in July. Foliar sprays of insecticides labeled against other bramble pests (including Brigade and Sevin) give some control of adults from late May until mid July, but applications must be timed to avoid bee kill. Pruning out and destroying galled canes is also recommended for rednecked cane borer control. If more than 5% of canes are galled, postbloom application of Admire Pro to soil for systemic uptake and control may be warranted. Do not apply Admire Pro prebloom or during bloom. Brigade applied to the base of canes when adults are active will give some adult control ... again, remember to avoid bee kill. For more information on these insects, check the Midwest Small Fruit Pest Management Handbook (http://ohioline.osu.edu/b861/) and the 2010 Midwest Small Fruit and Grape Spray Guide (http://www.ag.purdue.edu/hla/Hort/Documents/ID-169-2010.pdf) . Rick Weinzierl (217-333-6651; weinzier@uiuc.edu) Notes on prebloom and petal fall insecticides in apples and peachesA few key reminders on prebloom and petal-fall sprays in apples and peaches:
Rick Weinzierl (217-333-6651; weinzier@uiuc.edu) Less seriously ...Old Farmer's Advice: Keep skunks and bankers at a distance. University of Illinois Extension Specialists in Fruit and Vegetable Production & Pest Management
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