Managing Vineyard Diseases and Pests Anne DeMarsay and Joseph A. Fiola Maryland Cooperative Extension, Western Region Keedysville, Maryland

Integrated Crop Management Elements of ICM – Plant virus-free vines of disease- resistant varieties – Use good cultural practices  Bio-renovation/perennial weed control  Canopy management  Sanitation  Prevent winter injury to vines – Use biological control of pests where possible – Use chemical controls appropriate to diseases and pests

Bio-renovation Program Start in the spring 2 years before planting vines Start in the spring 2 years before planting vines Objectives Objectives – Increase organic matter in soil to improve fertility (nitrogen content and nutrient-holding capacity) and efficacy of herbicides – Reduce/eliminate residual herbicides – Reduce pathogenic nematodes to protect roots and avoid transmission of viruses – Control perennial weeds

Nematode Testing Nematode testing services available from the Plant Nematology Laboratory, Univ. of MD, College Park Nematode testing services available from the Plant Nematology Laboratory, Univ. of MD, College Park – Forms available from county Extension office or Plant Nematology Laboratory – Instructions for sampling at

Plant Pathogenic Nematodes © CABI Bioscience, Egham, UK, 2004 Sourced from Stylet on root-feeding nematode Courtesy U. Wyss, used by permission of the Society of Nematologists Sourced from Dagger nematode feeding on a fig root

Nematode Damage Left: grapevine roots damaged by lesion nematodes Right: a healthy root system ©Howard Ferris, Used by permission of author. Sourced from:

Benefits of Canopy Management Good canopy management promotes early ripening AND decreases fungal diseases of fruit Good canopy management promotes early ripening AND decreases fungal diseases of fruit – Allows sunlight to penetrate canopy – Increases air circulation and decreases humidity in canopy – Promotes early drying of leaves and clusters after dew or rain Avoid excessive fertilization, which can make canopy management more difficult Avoid excessive fertilization, which can make canopy management more difficult

Cultural Practices: Canopy Management Light exposure Air exposure Pesticide exposure

Cultural Practices: Weed Control Weeds harbor insects and may be hosts for diseases

Chemical Disease Control Chemical controls are effective for many fungal diseases but not bacterial or viral diseases Chemical controls are effective for many fungal diseases but not bacterial or viral diseases For maximum effectiveness: For maximum effectiveness: – Identify the disease and choose the right product – Follow the label—the label is the law! – Timing is critical

Chemical Disease Control Monitor weather conditions as well as crop phenology and adjust your spray schedule as needed

Chemical Disease Control  Buy the right sprayer and maintain it carefully  Calibrate your sprayer at the beginning of the season  Use the right nozzles and pressure for good canopy penetration  Use adequate spray volume for thorough coverage  Avoid drift

Pathogens of Grapes  Bacteria (crown gall, Pierce’s disease)  Fungi (powdery mildew)  Viruses (leafroll, tomato ringspot decline)  Phytoplasmas (grapevine yellows)

Major Fungal Diseases of Grape  Powdery mildew  Black rot  Phomopsis cane & leaf spot (and fruit rot)  Downy mildew  Botrytis bunch rot

Powdery Mildew Active (sporulating) leaf infections

Powdery Mildew Fruit cluster infection Older leaf lesions

Black Rot Fruiting bodies in leaf lesion

Black Rot Photos: Turner B. Sutton, by permission

Black Rot Photos: Turner B. Sutton, by permission

Lesions on shoot and rachis Lesions on young leaf (left) and older leaf (right) Photos: Midwest Grape Production Guide, Ohio State University Extension Bulletin 919, Columbus, Ohio, 2005, p. 71. Phomopsis Cane and Leaf Spot

Photos: Turner B. Sutton, by permission

Downy Mildew Young “oil spot” lesions on upper leaf surfaces Photo: J. Pscheidt, by permission. From

Downy Mildew “Cottony” sporulation on underside of leaf

Downy Mildew Sporulation on fruit clusters destroyed by DM

Botrytis Bunch Rot Sporulation on leaf lesion Shoot infection APS Small Fruits Digital Image Collection

Botrytis Bunch Rot Photos: (L) Turner B. Sutton, by permission; (R) APS Small Fruit Digital Image Collection

Insect Pest Management Take action against an insect pest only after: Take action against an insect pest only after: – You are certain the insect is present – The insect poses a threat to your crop Action threshold: the pest density that requires control to avoid economic damage Action threshold: the pest density that requires control to avoid economic damage Monitoring methods Monitoring methods – Scouting – Trapping Know the insect’s life cycle and activity in relation to vine phenology Know the insect’s life cycle and activity in relation to vine phenology

Biological Control of Pests Protect beneficial insects that prey on plant pests

Insect Pest Monitoring Methods Scouting for insects and damage

Insect Pest Monitoring Methods Pheromone traps

Insect Pest Monitoring Methods Colored sticky traps

Monitor Activity for Effective Control

Understand the Insect’s Life Cycle Grape root borer larva

Understand the Insect’s Life Cycle Grape root borer larvae feed for two years before pupating

Understand the Insect’s Life Cycle... And are best controlled as adult moths

Understand the Insect’s Life Cycle

Insect Control Options  Mating disruption with pheromones  Mass trapping, with or without pheromones  Parasitism/predation by natural enemies  Insecticides

Insect Pests on Foliage Leafhoppers cause “hopper burn”

Insect Pests on Foliage Japanese beetles skeletonize leaves

Insect Pests on Foliage Grape phylloxera forms galls on leaves and susceptible rootstocks

Pest Management Spray Program for a Non-Bearing Vineyard TimingTargetMaterials New shoots (start at ½ -1”) Every 10 days (3 sprays) Powdery mildewMancozeb plus a PM fungicide (sulfur, oil, an SI, Quintec, Endura) Pre-bloom to post-bloom Every 10 days (3 sprays) Powdery mildew Downy mildew Mancozeb plus a PM fungicide (sulfur, an SI, Quintec, Endura)

Pest Management Spray Program for a Non-Bearing Vineyard TimingTargetMaterials Cover sprays Every days until frost Powdery mildew Downy mildew Japanese beetle* Captan or a phosphite plus a PM fungicide (sulfur, an SI, Quintec, Endura) *Add Sevin to Jul-early Aug sprays (1 or 2)

References A Pocket Guide for Grape IPM Scouting in the North Central & Eastern U.S. A Pocket Guide for Grape IPM Scouting in the North Central & Eastern U.S. Guidelines for Developing an Effective Fungicide Spray Program for Wine Grapes in Maryland, 2008 (April 2008)— section on non-bearing vineyards Guidelines for Developing an Effective Fungicide Spray Program for Wine Grapes in Maryland, 2008 (April 2008)— section on non-bearing vineyards Home Fruit Production Guide, MD EB 125. Available for $8.00+ S&H from UMD Home & Garden Info Center: Home Fruit Production Guide, MD EB 125. Available for $8.00+ S&H from UMD Home & Garden Info Center: Other University pest management guides (Cornell-Penn State, Virginia Tech)—commercial and home gardening Other University pest management guides (Cornell-Penn State, Virginia Tech)—commercial and home gardening Dr. Wayne Wilcox, Cornell—annual notes on disease control Dr. Wayne Wilcox, Cornell—annual notes on disease control APS Compendium of Grape Diseases APS Compendium of Grape Diseases

Anne DeMarsay, Ph.D. Specialist in Fruit Pathology Maryland Cooperative Extension Central Maryland REC—Upper Marlboro 2005 Largo Road Upper Marlboro, MD Phone: (301) Got a Question?