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Kentucky Fruit FactsJuly Newsletter 2017 http://www.uky.edu/hort/documents-list-fruit-facts
John Strang, Extension Fruit Specialist, EditorDenise Stephens, Newsletter Designer
Inside this Issue: Fruit Crop News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Upcoming Meetings. . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Spotted Wing Drosophila Activity Intensifying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Brown Marmorated Stink Bug . . . . . . . . . . . . . . . . . .3 Cedar-Apple Rust . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Receiving Fruit Facts on the Internet . . . . . . . . . . . . 6
Fruit Crop News John Strang, U.K. Extension Horticulturist, Ric Bessen, U.K. Extension Entomologist, and Matt Dixon, U.K. Ag Meteorologist The heat units necessary for fruit crop development have accumulated very rapidly as reported in the March-April Fruit Facts and our fruit crops continue to develop well ahead of schedule. Figure 1 shows Lexington heat unit accumulations expressed as Growing Degree Days for 2017 in comparison with a number of previous years. This chart shows how fortunate we were in avoiding a severe spring frost and drastic fruit crop losses (2007, 2012, and 2015). As of July 6 plant development is running about two weeks earlier than normal. This translates into earlier harvests, but it also means that some pests are showing up considerably earlier than normal. This is particularly true for Japanese beetles and Spotted wing drosophila (SWD). Soil moisture from June through August greatly affects the capability Japanese beetles to emerge, lay eggs and for the eggs to survive. The wet spring and summer the last three seasons has led to high Japanese beetle numbers in some areas and this has taken some growers by surprise. Spotted wing drosophila trap catches have occurred particularly early this year and the mild winter allowed many more than normal to winter over. This has resulted in very high levels of egg laying.
Some blackberry and blueberry growers have already been alarmed to find high populations of worms in their fruit. This is not good for consumer confidence in Kentucky produce and can ruin our market. Many blueberry growers have not sprayed for SWD in the past, but this year may be an exception. Test for SWD in your fruit before taking them to market. Weekly preventative sprays are necessary for blackberry production and may be necessary for blueberry producers this season once this pest is trapped because of excessive numbers of SWD. Backyard growers may cover their plants with a fine meshed netting to avoid spraying. See the article by Ric Bessin on SWD that follows. Apple growers have generally been feeling pretty good about the crop so far. Expected fire blight infections based on high chances of infection throughout bloom generally resulted in few infections. Most other pests with the exception of Japanese beetles and Cedar apple rust have been at normal levels. I have notices an outbreak of Woolly apple aphids in our university orchard (see photo in masthead) here in Lexington and we have sprayed for them with Movento (PHI 7 days). I am a little perplexed by this buildup since we did not spray any synthetic pyrethroid sprays last or this season which kills Woolly apple aphid natural predators. The peach harvest and early apple harvest are going well. Peaches are in high demand due to a tremendous crop loss in Georgia and South Carolina caused by a lack of winter chilling and spring freezes. The strawberry crop this year was a difficult one for growers. Many plasticulture growers that planted on time ended up with larger than normal
Cooperative Extension Service University of KentuckyHorticulture Department1100 So. Limestone St.Lexington Ky 40546-0091(859) 257-2909Fax: (859) 257-2859extension.ca.uky.edu
plants with too many branch crowns due to the mild winter. This resulted in smaller than normal fruit. Excessive rainfall made harvest difficult and drastically increased fruit decay problems after harvest. Many matted row strawberry growers also had problems with excessive rain, U-Pick customer turnout, and smaller than normal fruit size. As a result some fruit did not get harvested.
Up Coming Meetings
July 24, University of Kentucky Viticulture and Enology Summer Field Day - UK Horticulture Research South Farm, 4321 Emmert Farm Lane, Lexington, Ky 40514. The event is free but please RSVP by July 21st to Patsy Wilson at [email protected] or text or call 859-494-1657.
Program:
9:00-9:15 a.m. Coffee and gather in farm classroom.
9:15 - 9:30 a.m. Walk to Vineyard
9:30 a.m.-12:00p.m. Vineyard Field Talks
12:15 p.m.-1:00 p.m. Lunch (farm classroom)
1:00 p.m.-3:00 p.m. Wine Working Group - Preparing for Harvest 3:00 p.m. Adjourn
Aug 13-16, Northern Nut Growers Association & North American Fruit Explorers Conference, University of Georgia Tifton Conference Center, Tifton, GA. See http://www.nutgrowing.org/meetinfo.htm for registration and conference information.
Jan 8-9, 2018 Kentucky Fruit and Vegetable Conference, Embassy Suites Hotel, 1801 Newtown Pike, Lexington, KY 40511. Contact John Strang Phone: 859-257-5685; Email: [email protected].
Spotted Wing Drosophila Activity Intensifying By Rick Bessin, U.K. Extension Entomologist
Samples, the week of June 27 indicate that spotted wing drosophila (SWD) activity is increasing across the state with numbers of these captured insects considerably higher at some locations. For the latest update consult https://www.facebook.com/swdinky/. While the threshold to begin management is ‘one captured fly,’ continued trapping provides information on relative activity and effectiveness of the management program. Simply determining if the population is increasing, decreasing, or staying the same can be very helpful.
Figure 2. This map shows the month of the first SWD capture in several counties.
Sampling Fruit In addition to using the SWD traps to capture adults, we also recommend sampling ripe undamaged fruit for larvae. Simply place about 20 berries in a sealable bag, and then add two cups water and 1/2 cup sugar. Mash the berries and look for the 1/8- to 1/4-inch white larvae floating to the surface.
Figure 3. The float test is a great method to evaluate effectiveness of SWD management programs (Photo: Ric Bessin, UK).
Management In terms of insecticide applications to manage these insects, once SDW have been captured on a farm (or if the farm is not trapping), consider beginning sprays at the first capture or a week before the start of the harvest period. Reapply sprays on a weekly basis. When there is a significant heavy rainfall event, a new spray may be needed. Producers need to rotate among modes of action with subsequent sprays and follow pre-harvest intervals (PHIs) carefully. Consult Spotted Wing Drosophila Management http://www2.ca.uky.edu/entomology/entfacts/entfactpdf/ef230.pdf or the spray guides for pesticides that work on SWD, reentry intervals and preharvest intervals.
Brown Marmorated Stink Bug By Dr. Ric Bessin, U.K. Extension Entomologist
Based on grower accounts during our winter Extension meetings in various counties, brown marmorated stink bug (BMSB) problems have increased in many areas within the state. The mild winter also favored higher survival of BMSB, as well. So, home gardeners and crop producers alike should be on the watch for this invasive pest as the season progresses. BMSB can damage all of our fruit crops, many vegetables, as well as corn and soybeans. It also will attack many different types of ornamental and wild host plants in the landscape (Figure 4). BMSB is considered a highly mobile pest, moving frequently from plant type to plant type
across the landscape and farmscape. Its movement is influenced by plant stage, phenology, and seasonal progression. On the farm, it is attracted to many of its hosts as the seed heads or fruit structures begin to develop. On diverse farms, it can move to different crops almost on a weekly basis. Damaged caused by BMSB depends on the type of plant it feeds upon with its piercing-sucking mouthparts. Damage can range from shriveled and discolored seeds to discolored corky areas in the flesh of fruit (Figure 5).
Figure 4. Brown marmorated stink bugs on Japanese millet. (Photo: Ric Bessin, UK)
Figure 5. Discolored cork spots on apple due to BMSB feeding. (Photo: Ric Bessin, UK)
Figure 6. Brown marmorated stink bugs can be monitored through the use of aggregation pheromone and black pyramid traps. (Photo: Ric Bessin, UK)
Monitoring There are several BMSB traps that are commercially available to monitor populations in the field. These include 4-foot black pyramid traps (Figure 6) and clear panel traps hung at the same 4-foot height. We are comparing these two trap types in Lexington and Princeton this year. These traps use aggregation pheromones to attract BMSB, but research has demonstrated that they often increased damage adjacent to these traps. It is best to place the traps just outside of the field, preferably along a tree line from which BMSB is likely to invade. Thresholds are still being developed based on numbers of trapped stink bugs, but ten BMSB per trap per week has been used as a threshold for control with apples when using the black pyramid trap.
Management
Insecticides BMSB is more difficult to control with insecticides than our other stink bug pests. Some of the pyrethroids, such as bifenthrin, fenpropathrin, and cyfluthrin, work well. Some of the neonicotinoids including dinotefuran, clothianadin, and thiamethoxam also work well. For homeowners, malathion is another alternative. Be sure to read the labels and only use insecticides appropriate to plants being treated.
Insect Netting In a home garden situation, fine netting can be used to keep BMSB from injuring produce. We have found that insect netting with holes at least 1/6 inch or smaller can be used to keep BMSB off plants. The netting needs to be in place before BMSB is attracted to the plants and should cover the plant entirely to the ground. The netting should be weighted down on the edges to prevent BMSB from crawling underneath.
Figure 7. These tiny wasps provide important control of stink bugs by killing their eggs. (Photo: Ric Bessin, UK)
Biological Control There are a number of insects that feed on BMSB eggs including lady beetles, katydids, and damsel bugs. Some of our native tiny wasp parasitoids (Figure 7) also attack the eggs, but at very low levels. Recently a Chinese wasp, which can provide high levels of parasitism of BMSB eggs, was discovered in the states of Maryland and Washington. UK entomologists will be surveying for this beneficial natural enemy of BMSB this year and next in Kentucky.
Cedar-Apple RustBy Kim Leonberger, Extension Associate and Nicole Ward Gauthier, Extension Specialist
Cedar-apple rust is the most common and economically important rust disease of apple in Kentucky. Symptoms of this disease are evident in unsprayed orchards across the state. The pathogen overwinters as galls on cedar and juniper. Removal of these pathogen sources on cedar can later reduce disease incidence on apple. Once apple trees become infected limited management options are available.
Cedar-Apple Rust Facts• Leaf symptoms begin as small, pale yellow spots on upper leaf surfaces (Figure 8). Spots enlarge to become bright yellow-orange, often with reddish borders (Figure 9). In late spring or early summer, small orange-yellow tubular fruiting bodies project from lower sides of leaf spots (Figure 10). Severely infected leaves may drop prematurely. Infected fruit exhibit similar symptoms with spots appearing near the blossom end; however, spots on fruit are much larger than those on leaves. Fruit may also become deformed and drop prematurely.
Figure 8: Leaf symptoms begin as small yellow spots on upper leaf surfaces. (Photo: Kim Leonberger, UK)
Figure 9: Leaf spots expand and become bright yellow-orange spots, often with reddish boarders. (Photo: Kim Leonberger, UK)
• Cedar-apple rust in known to infect apple, crabapple, hawthorn, mountain ash, pear, and serviceberry.
Figure 10: On undersides of leaf spots, small orange-yellow tubular fruiting bodies develop. (Photo: Nicole Ward Gauthier, UK)
• The pathogen requires more than one host to complete its life cycle. Cedar and juniper serve as alternate hosts. In mid-late summer, spores from apple spots are blown to cedar and juniper. Infection results in the formation of galls (swellings), which expand over a period of 2 years before producing spores that infect apples.• Primary infection of apples begins in early spring during leaf expansion and pink bud stage. Infections can continue until 30 days after bloom.• Damp conditions with temperatures between 50-60°F favors disease development.• Caused by the fungus Gymnosporangium juniper-virginianae
Management Options• Select apple and juniper cultivars that are resistant or immune to cedar-apple rust.• Maintain plant health with proper nutrition and
irrigation practices.• Destroy nearby unmanaged, abandoned, or wild hosts.• Prune and destroy galls found on juniper and cedar.• Fungicides may be used preventatively beginning at pink-bud stage through 30 days post- Homeowners may use fungicides that contain myclobutanil or mancozeb. Always follow label directions when utilizing fungicides.
Additional Information
• Apple Rust Diseases (PPFS-FR-T-05)• Backyard Apple Disease & Pest Management
Using Cultural Practices (with Low Spray, No Spray & Organic Options) (PPFS-FR-T-21)
• Midwest Fruit Pest Management Guide (Commercial Growers) (ID-232)
• Disease and Insect Control Programs for Homegrown Fruit in Kentucky including Organic Alternatives (ID-21)
• Fruit, Orchard, and Vineyard Sanitation (PPFS-GEN-05)
• Simplified Backyard Apple Spray Guides (PPFS-FR-T-18)
FRUIT HUMOR
He Takes Off His Yellow Jacket!
What Does a Bee Do When It is Hot?
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Cooperative Extension ServiceUniversity of KentuckyHorticulture DepartmentN-318 Ag. Science Ctr. No.Lexington KY 40546-0091
