Strawberry and Raspberry Pest Management in Wisconsin

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16 CULTIVAR SELECTION AND CULTURAL PRACTICES risk” because of their relatively low toxicity to humans and wildlife. However, many are at great risk of having fungal pathogens develop resistance to them. Most product labels include recommendations for resistance management, including limits on the number of sprays per season or number of consecutive sprays of a “resistance group.” Most labels specify a resistance group number, based on a fungicide’s mode of action and chemical class. For the purposes of resistance management, fungicides in the same resistance group are considered identical. For example, Abound is in resistance group 11. One component of Pristine is also a group 11 fungicide. Therefore, Abound and Pristine are equivalent in a resistance management program. One of the most effective ways to manage diseases of strawberries is by planting cultivars that are somewhat resistant to the most important diseases (table 5). However, even resistant cultivars can succumb to disease if the pathogen is present and conditions are favorable for disease development. Therefore, cultural practices that minimize disease development and spread are of paramount importance in producing strawberries. Planting sites should have good water drainage and good air drainage and circulation. Achieve proper air drainage by locating the plant somewhat above the surrounding topography, and proper air circulation by planting sufficiently dense windbreaks. Windbreaks reduce winter injury and encourage maximum growth. They also allow air circulation, which promotes drying of leaves and fruit. This drying, in turn, reduces disease incidence and severity. Also manage weeds and avoid excessive fertilization. (The latter can yield dense foliage.) Avoid soils with a history of strawberry root diseases (e.g., red stele or black root rot), and soils in which plants susceptible to the Verticillium fungus were planted within the past five years. These include but are not limited to potato, tomato, pepper, eggplant, brambles, rose, pumpkin, squash, cucumber, and melons. If pathogen-free soils cannot be avoided, soil fumigation should be considered. A sandy loam soil or a loamy sand soil with organic matter greater than 2% is ideal for general plant health and productivity. A layer of clean straw mulch will prevent fruit from infection by soilborne pathogens and may also reduce “splash dispersal” of pathogens during rain. Finally, purchase plants certified as “virus-free” from a reputable nursery. Table 5. Disease resistance ratings a of strawberry cultivars based on observations in Wisconsin Cultivar Angular leaf spot Fruit rots Leaf scorch Leaf spot Powdery mildew Red stele Verticillium wilt Annapolis VS S S S S S–VR b I–T Brunswick — T T R T R — Cabot — S T T T R S Cavendish VS T T T S R I–T Earliglow — R R S I R I Evangeline — T R T T S S Glooscap S S T T T VS S Honeoye VS R T T T S S a VS = very susceptible; S = susceptible; I = intermediate reaction; T = tolerant (disease symptoms evident, but with little detrimental effect on the plant or yield); R = resistant (the disease does not occur on this cultivar or only to a very small degree); VR = very resistant; — = unknown or untested. b Disease reaction depends on races of the pathogen. For more information, contact Brian Smith (715-425-3851) or Patty McManus (608-265-2047).
Table 5. Disease resistance ratings a of strawberry cultivars based on observations in Wisconsin (continued) Cultivar Angular leaf spot Fruit rots Leaf scorch Leaf spot Powdery mildew Red stele Verticillium wilt Itasca — — R T R R — Jewel VS R R R R S S Kent VS S VS VS T S S Mesabi — T T T T R — Mira S T R R R R S Sable VS S T T S R — Seneca — T S T — S S Sparkle S S–I I S R S–R b S Tribute — T T T R VR T–R Tristar T T T T R R R Wendy S T T S T T S Winona VS T R T T R — a VS = very susceptible; S = susceptible; I = intermediate reaction; T = tolerant (disease symptoms evident, but with little detrimental effect on the plant or yield); R = resistant (the disease does not occur on this cultivar or only to a very small degree); VR = very resistant; — = unknown or untested. b Disease reaction depends on races of the pathogen. For more information, contact Brian Smith (715-425-3851) or Patty McManus (608-265-2047). PREPLANT SOIL FUMIGATION To help ensure a productive planting, advanced planning and preparation of the site prior to planting are recommended. Although generally not recommended in Wisconsin, preplant soil fumigation may be beneficial where populations of soilborne pests are known to be high. Soil fumigants can help control soilborne fungi (e.g., Verticillium, Phytophthora), nematodes, soilborne insects, and weeds and also encourage vigorous root growth and plant establishment. Fumigate in late summer or early fall the year before planting. At planting, use pathogen-free plants obtained from a reputable nursery. DISEASE NOTES Note: Most fumigants are restricted-use pesticides and can be applied only by certified applicators. Custom applicators are available for hire. Angular leaf spot Angular leaf spot, caused by the bacterium Xanthomonas fragariae, is a sporadic disease in Wisconsin that can severely damage foliage and fruit. The disease is favored by cool, damp weather. Early symptoms on lower leaf surfaces are small water-soaked spots bordered by tiny veins. The spots appear dark green when viewed from above, but translucent and light green to yellow when held up to light. Under moist conditions, the spots ooze a milky substance which, upon drying, forms a thin, scaly film. The bacteria-laden exudate is readily spread by splashing water, so avoid using sprinklers to irrigate plantings infected with angular leaf spot. The pathogen overwinters in dead leaves; removing leaf debris from the bed after renovation will reduce inoculum for the following year. Most cultivars appear susceptible to angular leaf spot; the cultivar Honeoye appears to be especially susceptible. Chemical control of bacterial diseases is inconsistent. However, copper compounds (e.g., copper ammonium carbonate, copper hydroxide, and copper sulfate) are the chemicals most effective against angular leaf spot. If the disease was present last year, apply copper sprays as soon as growth starts in the spring. Additional applications at weekly intervals may be necessary if the weather is cool and humid. Plants are 17
Page 1 and 2: A1934 Strawberry & Raspberry Pest M
Page 3 and 4: INTEGRATED PEST MANAGEMENT FEDERAL
Page 5 and 6: PESTICIDES AND COMMUNITY RIGHT-TO-K
Page 7 and 8: Table 2. Examples of pesticides wit
Page 9 and 10: Table 3. Toxicity categories of pes
Page 11 and 12: Reportable spills involving SARA su
Page 13 and 14: Planter granular applicators can be
Page 15 and 16: Please note that this recycling pro
Page 17: Strawberry Disease Management Read
Page 21 and 22: Strawberry Insect Management INSECT
Page 23 and 24: Table 6. Spray schedule for strawbe
Page 25 and 26: Table 6. Spray schedule for strawbe
Page 27 and 28: Strawberry Weed Management A succes
Page 29 and 30: label for specific instructions on
Page 31 and 32: Table 8. Weed management for strawb
Page 33 and 34: Table 8. Weed management for strawb
Page 35 and 36: products are taken up through leave
Page 37 and 38: Raspberry Insect Management Several
Page 39 and 40: Table 9. Spray schedule for raspber
Page 41 and 42: Raspberry Weed Management Effective
Page 43 and 44: Table 10. Weed management for raspb
Page 45: SPRAY RECORD SHEET Date applied Mat

Strawberry and Raspberry Pest Management in Wisconsin

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