2014 Watermelon Disease Update
2014 Watermelon Disease Update
Fusarium Wilt
• Fusarium Wilt (Fusarium oxysporum f.sp. niveum)• Early season, soil borne, cool weather pathogen• Can be seed borne (more and more showing up in
greenhouses)• Control
• 5-7 year rotation• Resistant varieties/grafting• Planting Date• Controlling Nematodes helps• Quadris/Actigard• Proline Fungicide Labeled in 2014
Watermelon Fusarium Wilt Trials (inoculated)
0
10
20
30
40
50
60
70
80
90
100
3/25/2010 4/6/2010 4/18/2010
Proline Drench(3 floz)Proline Drench(5.7 floz)Quadris Drench(15.4 floz)Untreated
Fusarium wilt % incidence
0
10
20
30
40
50
60
70
80
90
100
4/8/2013 4/18/2013 4/28/2013
Proline Drench(3 floz)
Quadris Drench(15.4 floz)
Untreated
2013 Berrien Co. Grower Trial (not inoculated)
0102030405060708090
100 Proline (3 floz) drench
Proline (3 floz) drench + 2apps (5.7 floz) banded spray
Quadris (15.4 floz) drench
Quadris (15.4 floz) drench +2 apps (15.4floz) bandedsprayActigard (0.5 oz) banded atplant + 2 apps (.75 oz)
Untreated
Fusarium wilt % incidenceBare Ground Watermelons
2014 Watermelon FW Methods Trial (inoculated)
0
10
20
30
40
50
60
70
80
90
100
4/8/2014 4/15/2014 4/22/2014 4/29/2014 5/6/2014
Proline Drench (3 floz) atplant
Proline Banded Spray (5.7floz) at plant
Proline Drip applied (5.7floz) at plant + 2 apps
Proline Banded Spray (5.7floz) at plant+ 2 apps
Quadris Drench (15.5 floz)+ 2 apps
Untreated
e
Fusarium wilt % incidence
a
ab
bc
cd
Watermelon Grown on Plastic Mulch
c
2014 Proline FW Methods Wilt Trial (inoculated)
05000
100001500020000250003000035000400004500050000
Yield Lb/A
Proline Drench (3 floz) atplant
Proline Drip applied (5.7floz) at plant + 2 apps
Proline Banded Spray (5.7floz) at plant+ 2 apps
Proline Banded Spray(5.7floz) at plant
Quadris Drench (15.5floz) +2 apps
Untreated
a-c
bc
c
c
ab
Watermelon Grown on Plastic Mulch
a-c
Fusarium Wilt
• Proline, Quadris and Actigard have activity against Fusarium Wilt• Proline longer residual control than Quadris• Typically do not see phytotoxicity
• Application Method• At plant drench most effective • Not labeled for Pre-plant application
• Worker Safety Issues• Banded Spray has worked on bare ground watermelons• Banded spray application on plastic mulch not as effective (Multiple
applications better)• Drip applied may work but probably need multiple applications
(2wk) interval
Gummy Stem Blight
• Gummy Stem Blight (Didymella bryoniae)• Mid-Late season, Warm Weather, Foliar Pathogen• Driver of Fungicide spray program on Watermelons• Fungicides very effective against Gummy Stem Blight• Resistance Management Critical
Gummy Stem Blight
• Spray Chlorothalonil Products Early Season
• Late Season Fungicides (Resistance Management is Critical)• Luna Experence (Floupyram + Tebuconazole)• Inspire Super (Difenoconazole + Cyprodinil)• Proline (Prothioconazole)• Folicur + Generics (Tebuconazole)• Switch (Fludioxonil + Cyprodinil)
Triazole insensitivity toGummy Stem Blight
0100200300400500600700
LunaExperience
(10 floz)
InspireSuper
(20 floz)
Bravo(3 pt)
Switch(14 oz)
Tebuzol(8 floz)
Proline(5.7 floz)
Untreated
2013Attapulgus
2014VORC
2014Attapulgus
d-f
a
c-e ab
fefef #
c c
Gummy Stem Blight AUDPC
a
c
bc
ab
2014 Gummy Stem Blight Trial Locations
Gummy Stem Fungicide Rotations
• Luna Experience/ Inspire super rotation GOOD• Tebuconazole or Proline/Luna OK, • Tebuconazole or Proline/Inspire super OK• Switch rotation GOOD (Expensive)• Tebuconazole/Proline (BAD)• Tebuconazole/Tebuconazole (Very Bad)
Powdery Mildew
• Late Season Warm Weather Pathogen. Favors Dry Conditions.
• Pathogen harder to see on watermelon leaves• Apply Fungicides at fruit set• 2014 Reduced efficacy in the SDHI fungicides
2013, 2014 UGA Powdery Mildew Fungicide Trials
0100200300400500600700800900
20132014
Summer Squash Powdery Mildew Trials
Area Under Disease Progress Curve
f efe
c b
b
a
fef
d
a
c
aba
e
Powdery Mildew Fungicides
• Rotate Torino, Quintec, Proline or Procure• Reduced Efficacy of SDHI (Group 7) Fungicides in 2013
and 2014 (Luna Experience, Fontelis, Pristine)
2014 Disease Management Update
• Summary
• Tebuconazole resistance has been found in Gummy Stem Blight. Resistance management is critical. • Do not spray Tebuconazole back to back• Do Not Rotate Tebuconazole with Proline
• All of the SDHI Fungicides show lower efficacy for control of Powdery Mildew on Cucurbit Crops (Luna Experience, Fontelis, Pristine, Merivon)