Newsletter. M. Elena Garcia, Lorraine Berkett, Terry Bradshaw, Chris Benedict, and Marlys Eddy Friday, October 22, 2004

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1 Newsletter M. Elena Garcia, Lorraine Berkett, Terry Bradshaw, Chris Benedict, and Marlys Eddy Friday, October 22, 2004 Inside this issue: Horticulture News (M. Elena Garcia) 2 Grape Nutrition: Petiole and Soil Analysis 2 General nutrition factors to consider when determining the vineyard fertilizer program 3 Web Sources for Grape Information 5 Grape Mineral Nutrition Summary Table 6 IPM News (Lorraine P. Berkett) 8 Hello An Introduction 8 The 2004 Growing Season Some Observations 9 Disease Observations 9 Insect Observations 14 Contact Information 16

2 Horticultural News M. Elena Garcia, Tree Fruit Specialist Grape Nutrition: Petiole and Soil Analysis Optimal mineral nutrition is essential for high productivity and fruit quality. Growers should become involved in the long-term management of the vineyard nutritional needs in order to avoid problems of deficiencies and toxicities, maximize productivity, and reduce the application of unneeded fertilizers. Growers have at their disposal several tools to assist them in their nutrient management and these include petiole and soil analysis. Petiole analysis tells the grower what nutrients are in the plant whereas soil analysis tells what nutrients could be available from the soil. A discrepancy between what elements are available from the soil and what is in the plant might indicate problems with the soil ph, which can begin to be corrected by a lime application in the fall. It is a good idea to look at petiole and soil analyses as a way of saving money and preventing nutrient deficiencies, as well as toxicity problems. Nutrient toxicity problems can be as troublesome as deficiency problems. The results of these analyses will tell you whether you need a specific element or not and if your current fertilizer program is correct. Petiole analysis (to be conducted at veraison): Regular sampling is more valuable than using petiole analysis only when nutritional problems are evident because a series of analyses over a period of years can indicate approaching nutritional problems. Petiole analyses are a good indicator of the success of either fertilizer sprays or soil amendments. Petiole analysis can confirm visual symptoms that suggest deficiencies or toxicities. Using petiole analyses enable growers to better manage their vineyards. When specific deficiencies are identified, large responses are possible. Collecting petioles for analysis: Petiole collection is usually done at veraison Collection should be made of representative vines in the vineyard Usually a minimum of 100 petioles need to be submitted Leaf petioles opposite a fruit cluster should be collected UVM Grape Newsletter- Friday, October 22, 2004 page 2

3 Petioles of immature of senescing leaves should not be collected Do not mix petioles from different cultivars Petioles should be delivered to the laboratory within 24 hours of collection It is important to maintain consistency in sampling from year to year to be able to compare from year to year Soil analysis on a regular basis (to be done in the fall at least every third year). It is absolutely foolish to design a fertilizer program without knowing the ph because nutrient availability is ph dependent. Soil test can reveal a cause of a nutrient problem and is most useful when it supplements petiole analysis. If the petiole analysis suggests a deficiency and the soil analysis suggests adequate levels, one might suspect that additional factors are involved If low tissue levels are accompanied with low soil levels, the grower is much certain of the source of the problem. The most important soil test that could serve as a guide for the interpretation of foliar levels of Mn, Fe and Zn is soil ph. It is important to do a soil test in the fall to determine the soil s ph, the fertilizer needs for your vineyard, and make the necessary corrections for next year s growing season. Soil and petiole testing is available through UVM Agricultural and Environmental Testing Laboratory. If you want soil testing kits and instructions on how to collect the samples, you may call the soils lab at , me at , or you may write to: The University of Vermont Agr. and Env. Testing Lab Hills Science Bldg. Burlington, VT General nutrition factors to consider when determining the vineyard fertilizer program: Season differences: Concentration of mineral within any given tissue is a reflection of the nutrient uptake, growth stage, transport, and remobilization of the nutrient within the plant. Climatic factors affect all these processes and may explain some differences in mineral concentration that occur within the same tissue in different years. Transpiration and uptake can have profound effect on the elemental composition of the plant tissues. Temperature and soil moisture, coupled with relative humidity, determine the amount of transpiration from plant leaves. Nutrient availability for root uptake is a summation of those nutrients that are UVM Grape Newsletter- Friday, October 22, 2004 page 3

4 intercepted by plant roots, nutrients in the soil reaching the plant root by mass flow (nutrient and dissolved substances are transported in the flow of water to the root that results from transpirational water uptake), and those reaching the root by diffusion (the movement of nutrient and dissolved substances from a high concentration to a low concentration). Diffusion appears to be the main mechanism supplying K to the plant root while mass flow amounts for a large portion of the Ca. Thus, petiole K and Ca would be differently influenced not only by the soil supply, but also by soil moisture, air temperature, and transpiration. Plant vigor There is a concept of nutrient balance that states that if any element is deficient to the extent of limiting growth, when corrected, may result in deficiency of other elements because of the increased growth demands on the marginal supplies. Often when little or no growth happens, nutrients are often concentrated and deficiencies may not be apparent. Excessively vigorous vines may show deficiencies due to a dilution effect rather than an actual deficiency. Excessive vine growth due to too much nitrogen results in vine shading, and delayed fruit ripening. Vineyard floor management Cover crops and weeds change water relations, alter root distribution, change root temperatures, and compete for plant nutrients. Nutritional interactions The optimal value of one mineral element may depend on the levels of another and modifying one nutrient will likely alter another For example, adequate Zn levels may differ depending on the P status The sum of cations, (i.e., K, Ca, and Mg) in milliequivalents, usually is not changed. As one element is added, the other two usually decrease. Increasing the application of K or Mg is reflected not only in a decrease in the foliar concentration of the element not applied, but foliar levels of Ca are often decreased High K levels could result in lowering of Ca and Mg by 40 and 50%, respectively. Increasing the N supply can result in decreases in petiole levels of several elements. Additional references and websites used in this issue: Viticulture Newsletter May Oregon State University Hart, J. Fertilizer and Lime Materials FG UVM Grape Newsletter- Friday, October 22, 2004 page 4

5 Soils and Fertilizers, LIVE Cornell University- Why soil and petiole analysis For a very good presentation on diagnosing and monitoring (with great pictures) grape nutrition go to: Web Sources for Grape Information Cornell Viticulture Grape Breeding and Enology Projects- University of Minnesota Iowa State University Michigan State University- Horticulture Grapes Minnesota Grape Growers Association University of Nebraska Viticulture Program Northwest Berry and Grape- Oregon State Univeirsity Oregon State University- Understanding grape development Ontario Agriculture and Foods Penn State- Small Scale Fruit Production Guide Tulare County Grape Publications- UC Davis Wine grape varieties for Michigan UVM Grape Newsletter- Friday, October 22, 2004 page 5

6 Table 1. GRAPE MINERAL NUTRITION SUMMARY PLANT MOBILITY DEFICIENCY SOIL MOBILITY NUTRIENT PHYSIOLOGY NORMAL PETIOLE Mobility of each element varies with both the soil and within the plant Mobility of each element varies with both the soil and within the plant Deficiency symptoms are important indicators of a nutrient deficiency or imbalance RANGE Petiole analysis results in this range should be considered ideal for maintaining tree health, adequate vigor, and fruit quality An appreciation for the complex physiological role played by mineral nutrients helps explain their importance in orchard nutrition Capitalized nutrientsare of macronutrients and nutrients in lower case letters are micronutrients Immobile Mobile NH4+ Immobile NO3- Mobile % Older leaves affected first. Leaves are small, uniformly light green or yellowish, reduced vigor, enhanced senescence of older leaves, upright leaf petiole angle, uniform chlorosis in mature leaves, reddish petioles, premature shoot lignification NITROGEN (N) Primary building block for all plant partsleaves, shoots, roots, fruit buds etc. Amino acids, proteins, chlorophyll. Yeast need N to remain viable during fermentation Immobile Mobile % Reddening of young leaves post POTASSIUM (K) Enzyme activator, flowering (white varieties), reddening spreads towards mature leaves leading to tip and marginal scorch necrosis, leaf rolling, browning (post veraison), leaf drop and halt in berry maturation (extreme deficiency) necessary for the formation and translocation of sugars, proteins, plant growth hormones, ATP (energy metabolism CALCIUM (Ca) Component of cell wall, membrane permeability, enzyme cofactor UVM Grape Newsletter- Friday, October 22, 2004 page 6 Immobile Very Immobile 1.26 to 3.0 % Deficiency symptoms difficult to identify in leaves. Necrosis of young leaves and apex Immobile Mobile 0.46 to 1.25 % Interveinal necrosis or chlorosis of mature leaves slowly moving towards younger leaves, leave lesions at flowering (extreme deficiency), premature leaf drop, can result in reduced sugars in berries MAGNESIUM (Mg) Molecular component of chlorophyll ; enzyme activator

7 Table 1. GRAPE MINERAL NUTRITION SUMMARY (Cont) NUTRIENT PHYSIOLOGY NORMAL PETIOLE RANGE PHOSPHOR OUS (P) Cellular energy transfer and storage; nucleic acid component or regulator cofactor Sulfur (S) Component of amino acids, proteins, coenzyme A DEFICIENCY SOIL MOBILITY 0.11 to 0.35% Reduced growth with no specific symptoms, some reports indicate reddish petioles and veins, weeping foliage, reduced internode length and fruit set (extreme deficiency) Uniform chlorosis of young leaves or immature leaves PLANT MOBILITY Very Immobile Mobile Mobile Slightly mobile Boron (B) Membrane integrity, translocation of Ca, sugars, plant hormones Zinc (Zn) Component or regulator cofactor of enzymes, plant hormones proteins (i.e.. aids in normal growth and fruiting) Manganese (Mn) Aids in chlorophyll synthesis; involved in photosynthetic oxygen evolution Iron (Fe) Required for chlorophyll formation; a chlorplast enzyme component 25 to 50 ppm zig-zag shoot, bleached spots on leaves (yellowish white on white varieties and reddish on red varieties), deformation or necrosis of young leaves and apex, lignified canes, dry inflorescences resulting in flower drop, small soft fruit, mummified fruit 41 to 100 ppm stunted shoot growth, small fanshaped leaves that roll upwards and thicken, stunted petioles, short and flat internodes, increased lateral shoots, deformation or interveinal/ blotched chlorosis of young leaves and apex 61 to 650 ppm interveinal/blotched chlorosis of mature leaves moving to young leaves and apex, leaf blade rolls up, small clusters difficult to ripen 31 to 100 ppm Chlorosis of tip leaves while veins remain green. Shoot growth is stunted and may die back. Mobile Very Immobile Very Immobile Immobile Very Immobile Immobile Immobile Copper (Cu) Important enzyme component 6.0 to 20.0 ppm Necrosis of young leaves and apex Very Immobile Immobile UVM Grape Newsletter- Friday, October 22, 2004 page 7

8 Cold Climate Grape IPM News Lorraine P. Berkett, IPM Specialist September 2004 Hello An Introduction I thought I would just take a moment to introduce myself to those whom I have not met. My name is Lorraine Berkett and I am really excited about working in the area of Grape Integrated Pest Management (IPM). My educational background is in plant pathology and entomology and have years of experience working with Vermont apple growers. Grapes is a new crop for me so I will be learning right along with you. I hope to apply by background and experience to address some of the disease and insect challenges that you and the emerging grape industry in Vermont will face as the vines mature and more acreage is planted. What is IPM? IPM has many definitions. The one that I often use is: Integrated Pest Management (IPM) is a sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and environmental risks. (National Coalition on IPM) Pests not only refer to insects but also to other arthropods such as mites, pathogens that cause disease, weeds, and vertebrates such as birds, voles, raccoons, deer, etc. IPM is based on knowledge - - such as knowledge about the biology of the different pests, how they interact with the crop, and how the environment/weather affects this interaction. IPM is also information-driven - - information on the development stage of particular pests, size of the pest population ( i.e., whether threshold levels have been reached that require action), and whether there are sufficient natural predators in your vineyard which might manage a pest situation without your intervention. Is IPM organic? It can be depending on what management tools and options are used. It is an approach to managing pests that is compatible with sustainable agriculture and organic agriculture. It is my intent to try to address your priorities and needs in terms of Grape IPM. If you ever have any questions or comments, please do not hesitate to contact me at 802/ or lorraine.berkett@uvm.edu. I look forward to working with you! UVM Grape Newsletter- Friday, October 22, 2004 page 8

9 The 2004 Growing Season Some Observations As you begin to harvest your grapes, it is always good to make mental notes as you are in the vineyard and then written notes afterwards of what disease or insect problems appeared on what cultivars and where in your vineyard. Were there differences between cultivars in the incidence or severity of a particular disease or insect damage? Was there more damage along the border of your vineyard or was it spread throughout? These notes are helpful during the winter as you review the effectiveness of your pest management program and make plans for the next year. Disease Observations. With all the wet weather we had during the growing season the potential for disease development was very high. In that respect, it was a good year to see the extent of disease problems that can occur under very favorable conditions and also how effective disease management programs were. However, it was not such a good year if you ended up with more disease than expected in your vineyard! With your help and with some of the data I have collected and will continue to collect on disease incidence on different cultivars, I hope to develop over the next two growing seasons a relative disease susceptibility table that includes the new University of Minnesota and Swenson cultivars. This type of table already exists for the classic European Vitis vinifera cultivars and the French-American hybrids. It is important to evaluate the newer cold climate grape cultivars because their level of resistance to particular diseases may allow them to be grown with fewer fungicides. Data from this year are not summarized yet but I thought you might be interested in seeing what was observed in Vermont vineyards this year. The following are snapshots of the diseases that were observed: Powdery Mildew on Leaves, Shoots, and Berries Severely infected leaf with both white mycelium (fungal thread-like growth ) and small black fruiting bodies (cleistothecia) on leaf surface. UVM Grape Newsletter- Friday, October 22, 2004 page 9

10 Individual powdery mildew lesions on surface of leaf. Powdery mildew lesions on stem. Powdery mildew on berry. Note: Three percent infection of berries with powdery mildew is said to produce an off-flavor in wine. UVM Grape Newsletter- Friday, October 22, 2004 page 10

11 Black Rot on leaves, petioles, and berries Typical black rot lesions Close-up of black rot lesion with small black fruiting bodies. Black rot lesions on leaves, petioles, peduncle, rachis, and berries (mummies). UVM Grape Newsletter- Friday, October 22, 2004 page 11

12 Downy Mildew on leaves, tendrils, and berries Downy mildew on underside of leaf. [This particular picture was taken at the Univ. of MN Hort. Res. Center although the same symptoms were also observed in Vermont vineyards.] Downy mildew on tendrils Downy mildew on berries UVM Grape Newsletter- Friday, October 22, 2004 page 12

13 Angular Leaf Scorch Symptom on leaf. Damage on some cultivars was very prevalent and in some instances it was more severe than pictured here. Other diseases observed in Vermont in 2004: Crown Gall, Botrytis bunch rot Specific information on grape diseases can be found at the following websites: Powdery Mildew - Black Rot - Downy Mildew - Angular Leaf Scorch - Crown Gall - Botrytis Bunch Rot - UVM Grape Newsletter- Friday, October 22, 2004 page 13

14 Insect Observations. The following are examples of insect damage observed in The most serious damage appeared to be caused by Grape Berry Moth whose larvae feed in berries and then damaged berries are infected by berry-rotting fungi such as Botrytis. Phylloxera damage Feeding damage ( i.e., stippling - small whitish dots ) along the leaf veins caused by the grape leafhopper. When damage becomes severe, leaves look whitish. Webbing of the grape berry moth larvae. Example of substantial damage caused by the grape berry moth and Botrytis that infected damaged berries. UVM Grape Newsletter- Friday, October 22, 2004 page 14

15 Other insect pests observed in Vermont in 2004 include Mealybugs and Japanese beetles. Also observed were beneficials (e.g., natural predators) such as lady bug beetles, immature stage of the lacewing insect, and predacious mites. Predacious mites were observed on grape leaves when viewed under the microscope. Specific information on grape insect pests can be found at the following websites: Grape Berry Moth - Grape Leafhopper - Phylloxera - Mealybug - UVM Grape Newsletter- Friday, October 22, 2004 page 15

16 Contact Information A Commitment to Excellence and Service: If you have any questions or want to arrange a vineyard visit please call or write. For horticulture questions contact: M. Elena Garcia Tree Fruit Specialist Dept. of Plant & Soil Science University of Vermont Burlington VT Phone: 802/ Fax: 802/ elena.garcia@uvm.edu For IPM questions contact: Lorraine P. Berkett Plant Pathologist and IPM Specialist Dept. of Plant & Soil Science University of Vermont Burlington, VT Phone: 802/ Fax: 802/ lorraine.berkett@uvm.edu Where trade names or commercial products are used for identification, no discrimination is intended and no endorsement is implied. Always read the label before using any pesticide. The label is the legal document for the product use. Disregard any information in this newsletter if it is in conflict with the label. The Vermont Agricultural Experiment Station, University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status. UVM Grape Newsletter- Friday, October 22, 2004 page 16