web2001 5 potato fungicide

Slide1: 

W. R. Stevenson UW – Madison, Plant Pathology One Step Forward . . . and Two Steps Back

Slide2: 

Potato Late Blight

Slide3: 

Potato Late Blight

Slide4: 

Potato Late Blight

Slide5: 

Potato Early Blight

Slide6: 

Potato Early Blight

Slide7: 

Pink Rot

Slide8: 

Silver Scurf

Slide9: 

Rhizoctonia

The 2000 Growing Season At A Glance: 

The 2000 Growing Season At A Glance Early start to the planting season Excess rainfall in late May and early June Abundant rainfall during July, August, early September Warm, but not hot temperatures throughout summer Relatively even growing season without temp or heat stress Excessively warm temperatures during harvest and early storage along with period of nighttime frosts

The 2000 Growing Season At A Glance: 

The 2000 Growing Season At A Glance The outcome during the growing season: Accumulation of 18 severity values by June 1 Appearance of first late blight in first half of June Subsequent scattered late blight statewide, but no widespread epidemic Intense fungicide spraying - statewide Minimal early blight The appearance of a smooth, high quality crop Large tubers with high dry matter

The 2000 Growing Season At A Glance: 

The 2000 Growing Season At A Glance The Outcome: At Harvest and Early Storage Swollen lenticels at harvest Pink rot observed at harvest Some late blight on tubers Unusually high levels of bruising Warm tubers at harvest Field frost Inability to cool tubers in early storage Unwanted moisture in early storage Reduced air circulation with cool nighttime air

The 2000 Growing Season At A Glance: 

The 2000 Growing Season At A Glance The Outcome: Film of water on tubers at harvest Inability to control bin temperatures Symptoms of leak, bacterial soft rot, pink rot, late blight Appearance of mold on tubers – generally saprophytic molds Loss of stored potatoes to combination of problems

Potato Disease Management: 

Potato Disease Management Storing warm tubers > 65 F increases risk of decay Action: Discontinue harvest when pulp temp > 65 F Film of water on tubers at harvest or sweating in storage increases risk of decay Action: maintain air circulation to remove excess moisture Tuber respiration increases up to 25 fold in the first 24 hr after harvest Consequence CO2  O2  Action: maintain air circulation at these critical times

Potato Disease Management: 

Potato Disease Management Shutting off fans when outside air temp > pile temp Failure to remove surface moisture Decrease in available O2 Increase in pulp temperature Increase in risk of soft rot decay Potential for tuber black heart Increased risk of storage losses

Potato Disease Management: 

Potato Disease Management The question of Quadris use Testing in WI since 1996 EUP in 1998 – 16 growers with split fields Full label in 1999 Allegations in 2000 regarding: Plant height Tuber skinning Tuber bruising Tuber decay at harvest Tuber decay in storage Fry color

Potato Disease Management: 

Potato Disease Management Quadris evaluation trials Paired comparisons multiple varieties with and without Quadris application No observed differences in: Plant height or vigor Tuber skinning or bruising at harvest Tuber decay at harvest Tuber decay in storage Fry color

Benefits of Quadris Treatment: 

Benefits of Quadris Treatment Since 1996 – multiple trials – Hancock, Spooner, grower trials Standard program: Three sprays beginning at row close and alternated with protectant (mancozeb or chlorothalonil)

Benefits of Quadris Treatment: 

Benefits of Quadris Treatment Observations: Consistent and excellent control of early blight and late blight Control of Rhizoctonia stem canker and black scurf Reduced incidence of black dot Improved crop health, yield, tuber size Improved yield, larger tubers Reduced amounts of a. i. Cost effective

Potato Disease Management: 

Potato Disease Management Question If we are achieving a high level of blight control at Hancock with high disease pressure, why are many growers having poor control with much higher inputs ?????

Benefits of Quadris TreatmentHancock Potato Trial, 2000: 

Benefits of Quadris Treatment Hancock Potato Trial, 2000 AUDPC - Combined Foliar Disease Severity - Combined LSD (P=0.05) = 0.05

Benefits of Quadris TreatmentHancock Potato Trial, 2000: 

Benefits of Quadris Treatment Hancock Potato Trial, 2000 US #1 cwt/A

Slide23: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Selected Treatments Foliar Disease Severity - Combined AUDPC - Combined Standards

Slide24: 

Standards Potato Fungicide Trial - Hancock, WI - 2000 AUDPC and Yield Yield (cwt)/A AUDPC - Combined

Potato Fungicide Trial - Hancock, WI - 2000Efficacy, Active Ingredient and Toxicity Units: 

a. i. (lb/A) Potato Fungicide Trial - Hancock, WI - 2000 Efficacy, Active Ingredient and Toxicity Units Toxicity Units AUDPC Standards

Slide26: 

Foliar Disease Severity – Early Blight AUDPC Standards Potato Fungicide Trial - Hancock, WI - 2000 Early Blight Control – Promising Experimentals Efficacy Early Blight Combined

Slide27: 

Standards Potato Fungicide Trial - Hancock, WI – 2000 Promising Experimentals – Early Blight Control AUDPC and Yield Yield (cwt)/A AUDPC Early Blight Combined

Slide28: 

Foliar Disease Severity – Late Blight AUDPC Potato Fungicide Trial - Hancock, WI - 2000 Late Blight Control – Promising Experimentals Efficacy Late Blight Standards Combined

Slide29: 

Standards Potato Fungicide Trial - Hancock, WI – 2000 Promising Experimentals – Late Blight Control AUDPC and Yield Yield (cwt)/A AUDPC Late Blight Combined

Potato Disease Management: 

Potato Disease Management New Products in the Pipeline Gavel – registration likely for 2nd quarter 2001 Headline (BAS 500) – possible registration in 2002 Tanos – possible registration in 2003

Slide31: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types

Slide32: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Excellent wear life - ideal for abrasive spray materials. Produce smaller droplets for thorough coverage. Spray pressure - 40-300 PSI

Slide33: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Excellent spray distribution over a wide range of pressures - 15-60 psi Reduces drift at lower pressures, better coverage at higher pressures

Slide34: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Large droplet size Droplets contain air bubble, shatter on impact with target Spray liquid enters nozzle Air drawn in through side port Air + liquid mix Mixes air with the liquid being sprayed to produce large air-filled droplets Large spray droplets reduce drift Improved crop penetration Excellent target cover and retention Venturi technology all contained in the nozzle tip makes it very economical.

Slide35: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Penetrates crop residue or dense foliage Smaller droplets for thorough spray converge Nozzle spacing: 20 inches Spraying pressure: 30 to 60 PSI

Slide36: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Uniform coverage in broadcast spraying Larger droplets for less drift - large, air-filled drops through the use of a venturi air-aspirator Excellent wear characteristics

Slide37: 

Potato Fungicide Trial - Hancock, WI - 2000 Early and Late Blight Control – Nozzle Types Foliar Disease Severity - Combined AUDPC - Combined

Slide38: 

Potato Fungicide Trial - Hancock, WI - 2000 AUDPC and Yield – Nozzle Types Yield (cwt)/A AUDPC - Combined Standards

Potato Fungicide Trial - Hancock, WI - 2000Active Ingredient and Toxicity Units – Nozzle Types: 

Active Ingredient (lb/A) Potato Fungicide Trial - Hancock, WI - 2000 Active Ingredient and Toxicity Units – Nozzle Types Toxicity Units Standards

Promising VarietiesHancock Potato Trial, 2000: 

Promising Varieties Hancock Potato Trial, 2000 AUDPC - Combined Foliar Disease Severity - Combined Yield (cwt/A)

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