hausbeck fighting phytophthora 08
DESCRIPTION
2008 APS meeting, Phytophthora WorkshopTRANSCRIPT
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Managing Managing Phytophthora Disease Phytophthora Disease
with Fungicideswith Fungicides
M.K. Hausbeck, A.P. Keinath, M.K. Hausbeck, A.P. Keinath, C.S. C.S. KousikKousik, and M.E. Matheron, and M.E. Matheron
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Phytophthora capsiciPhytophthora capsici Host RangeHost RangeCucurbitaceaeCucurbitaceae
SolanaceaeSolanaceae
FabaceaeFabaceae
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Crops at RiskCrops at Risk
Hot pepperHot pepperPumpkinPumpkin
Wax beanWax beanBell pepperBell pepperMuskmelonMuskmelon
Snap beanSnap beanZucchiniZucchiniHoneydew melonHoneydew melon
Lima beanLima beanWinter squashWinter squashGourdGourd
TomatoTomatoWatermelonWatermelonCucumberCucumber
EggplantEggplantSummer Summer squashsquashCantaloupeCantaloupe
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One size does not One size does not fit all!fit all!
Several approaches Several approaches are needed.are needed.
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PhytophthoraPhytophthora--infested site:infested site:
++
++
Irrigate Irrigate sparingly sparingly
from from wellwell
Crop Crop rotationrotation
Harvest Harvest earlyearly++
Destroy Destroy diseased diseased plantsplants
++Fungicide Fungicide
sprays sprays intensiveintensive
++Plant Plant resistanceresistance++
Raised Raised 88"" bed, bed, black black
plastic, plastic, trickle, trickle, subsoilsubsoil
++Soil Soil
fumigafumiga--tiontion
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Growing StrategiesGrowing StrategiesRaised beds, black plastic, and drip Raised beds, black plastic, and drip irrigation are a key strategy.irrigation are a key strategy.Water management through improved Water management through improved drainage and subdrainage and sub--soiling.soiling.Avoid planting in the low areas of fields.Avoid planting in the low areas of fields.
Flat vs Raised Raised/plastic/compost vs Raised
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Each growing system offers Each growing system offers unique challenges:unique challenges:
Short vs. long production time.Short vs. long production time.
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Each growing system offers Each growing system offers unique challenges:unique challenges:
Hand vs. mechanical harvest.Hand vs. mechanical harvest.
PHI PHI –– plays a significant role plays a significant role for some crops.for some crops.
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Cucumber Cucumber vines appear to vines appear to
be relatively be relatively tolerant to tolerant to
PhytophthoraPhytophthora
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1", 3", 5" fruit
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Inoculation TechniqueInoculation TechniqueInoculum Plug
Pathogen Pathogen sporulationsporulation WaterWater--soakingsoaking
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Sporulation density (0-3 scale)0: none1: light sporulation2: moderate sporulation3: heavy sporulation
Sporulation diameter (cm)
Lesion diameter (cm)
Disease EvaluationDisease Evaluation3 days post3 days post--inoculationinoculation
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Is there a difference betweenAcrobat and Gavel?
Num
ber o
f inf
ecte
d fr
uit
0
10
20
30
40
50
60
70
Trial 2Trial 3
Treatments applied at 1", 3", 5" sized fruit
Acrobat 50WP 6.4 oz+ Kocide 200054WG 1.5 lb
Gavel 80WG 2 lb+ Kocide 200054WG 1.5 lb
Untreated
Conventional nozzles
Pickling Cucumber
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Does Captan work?
Infe
cted
frui
t at h
arve
st
0
200
400
600
800
1000
1200Treatments applied when fruit
reached 1", 3", 5" in sizeb
Forum6.2 fl oz+ Kocide
1.5 lb(1",3",5")
Gavel 2 lb+ Kocide
1.5 lb (1") Acrobat6.4 oz
+ Kocide1.5 lb (3",5")
Forum6.2 fl oz+ Kocide
1.5 lb+ Manzate
2 lb(1",3",5")
Gavel 2 lb+ Kocide
1.5 lb (1",3")Acrobat6.4 oz
+ Kocide1.5 lb (5")
Captan6 lb
+ Kocide1.5 lb
(1", 3",5")
a a a a aUntreated
5" rain event
Pickling Cucumber
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Spray Spray RigsRigs
Conventional Conventional nozzlesnozzles
AirAir--assistedassistednozzlesnozzles
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Does spray coverage make a difference?In
fect
ed fr
uit a
t har
vest
0
50
100
150
200Three sprays were applied.
All treatments were tankmixed with Kocide 2000 1.5 lb/A.Bars with letters in common are not signicantly different.c
a
bab
Air-assisted Conventional nozzles
ab
UntreatedAcrobat 50WP
6.4 ozGavel 75DF
2.0 lbZoxium 80WP
5.0 ozAcrobat 50WP
6.4 oz
Pickling Cucumber
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On many farms,On many farms,PhytophthoraPhytophthora has become has become resistant to resistant to RidomilRidomil used used
for control.for control.
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18 Aug
Plan
t dea
th (%
)
0
20
40
60
80
a
c
ab
bc
aab ab
abab
Untreated V-101625.73FL1.75 pt____________________~drench 7 days after
transplant~
RidomilGold1.6 pt
RidomilGoldBravo
2 lb_________~7-day
foliar spray~
IR61410.21 lb +
Remedier2.2 lb
Remedier4WP2.2 lb
____________________~drench 7 daysbefore and after
transplant~
IR614150WP2.1 lb
RidomilGold EC25.6 fl oz____________________
~drench 7 daysafter transplant~
____________________~drench 32 daysafter transplant
and 29 daysbefore harvest~
IR614150WP2.1 lb
RidomilGold EC25.6 fl oz
_________~7-dayfoliar
spray~
Rates are per A.Bars with a letter in commonare not significantly different.
Pepper
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Can Fumigation Work?Can Fumigation Work?Fumigation StudiesFumigation Studies
Fumigation under plastic mulch.Fumigation under plastic mulch.––Very effective when combined Very effective when combined
with raised bed, black plastic, and with raised bed, black plastic, and drip irrigation.drip irrigation.
––Growers of fresh market Growers of fresh market vegetable crops have used this tool vegetable crops have used this tool to successfully control to successfully control P. capsiciP. capsici in in combination with cultural combination with cultural strategies and fungicide sprays.strategies and fungicide sprays.
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UntreatedUntreated MBr/PicMBr/Pic
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Making the Most of Making the Most of FungicidesFungicides
Maximize fungicide coverage.Maximize fungicide coverage.Keep spray intervals short.Keep spray intervals short.Apply Apply beforebefore a rain.a rain.Come back quickly Come back quickly afterafter a rain.a rain.Protect the fruit.Protect the fruit.Rotate with fungicides Rotate with fungicides proven to be proven to be helpful.helpful.Tank mixes can be helpful and are Tank mixes can be helpful and are required by some labels.required by some labels.