Managing Pests & Disease in the Vineyard Michael Cook
Who is this guy?
Challenges Facing Growers 1) Pierce s Disease 2) Pest & Disease Pressure fungal 3) Late Freeze 4) Rain excess and timing 5) Vigor 6) Variety Selection 7) Hail 8) Labor 9) Suppliers 10) Education
Diseases
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The Environment Precipitation Heavy Dew High Humidity Levels (dense canopy)
Proper Canopy Architecture is CRITICAL
How to keep an open canopy in Texas Manage vine vigor irrigate but do not over irrigate be judicious with fertilizer applications, especially N conduct good canopy management practices leaf removal, shoot thinning, summer pruning It s a constant battle of vegetative growth, it needs to be managed
The Pathogen Spores are present on wild grapes tolerant cultivars neighboring vineyards old wood that was previously infected pruning trash vineyard floor The pathogen is here, its just a matter of time your vineyard sees them!
Host No single variety tolerant of all fungal pathogens Table courtesy of Dr. Justin Scheiner
Fungal Pathogens Dormant Trunk Diseases Anthracnose 1 Shoots Phomopsis Powdery Mildew 3-5 Shoots Phomopsis Black rot Powdery Mildew Images courtesy of Dr. Justin Scheiner 10-12 Shoots Phomopsis Black rot Powdery Mildew Downy Mildew
Anthracnose Distribution: everywhere except West TX Conditions for infection: 12 hrs. of leaf wetness, 36 to 90 o F wet conditions promote further spread
Phomopsis Distribution: statewide Conditions for infection: rainy weather during early season leaf and cane lesions typically appear in 3 to 4 weeks Images from: Dr. Justin Scheiner and Fritz Westover
Black Rot Distribution: statewide Conditions for infection: 50 o F and leaf wetness at optimal temperature (80 o F), only 6 hours of leaf wetness is required Images from: Cornell Cooperative Extension Disease ID Sheet No. 102GFSG-D4
Powdery Mildew Distribution: statewide Conditions for infection: 50 o F and 0.1 rain moisture is not required after initial infection
Downey Mildew Distribution: everywhere except West TX Conditions for infection: 52 o F and 0.1 rain 4 to 5 day cycle if conditions are favorable (warm and moist)
Fungicides When are grapes susceptible to disease? All season most critical period is 2 weeks before bloom through 4-6 weeks post-bloom use your best systemic products at this time Grape varieties + phenology + diseases + weather + fungicides
Fungal Control Solutions 1. Develop your own spray management strategy 2. Scout for disease, not just on the weekends 3. Keep that canopy open 4. Monitor weather conditions as if you were a meteorologist 5. Keep good spray notes 6. Be adaptable (do not rely on a rigid spray plan) 7. Change nozzles/filters and calibrate sprayer
Rotate to Prevent Resistance
Follow the Label..It s the Law!
Grapevine Trunk Diseases (GTD s) over 20 fungal pathogens responsible, usually found as a complex slow spreading disease symptoms more noticeable with older vineyards spread by injury (pruning wounds, freeze damage, etc.) looking for dead spots, internal tissue discoloration, splits/cracks, foliar symptoms
Eutypa Images courtesy of Dr. Justin Scheiner
Esca
Cotton Root Rot (CRR) found on calcareous sites (soil ph 7.0 +) found across the state look for vine collapse during stress periods, leaves attached vine often pulls out of ground easily (roots rotted) confirm by sending off sample to lab Rogue or Topguard Terra Image courtesy of Dr. Justin Scheiner
Bunch Rots Botrytis Bitter Rot Sour Rot Ripe Rot
Bunch Rots Spread via wounding Fruit splitting/cracking Insect Damage Fungal Damage Vertebrate Damage
Bacterial Diseases Crown Gall Pierce s Disease Crown Gall Agrobacterium vitis Survives systemically Injury (freeze, weed eater) activates Leads to vine decline and death ROGUE NO CURE
Disease Testing
Insect Pests
Insect Solutions Manage pest population Chemically with insecticides foliar spray or chemigation Culturally clean up property suppress weeds Biologically most not economically feasible commercially
Pheromone Traps
Get ready for a great 2018! 1. check stock of chemicals/fertilizers 2. vine health check disease management 3. Chemigation/irrigation inspection 4. sprayer calibration check nozzles & output 5. go over spray management program
Further Resources winegrapes.tamu.edu Growing Grapes in Texas Jim Kamas Texas Grape Pest Management Guide Compendium
Any Questions? m.cook@tamu.edu Texas Viticulture & Enology