Abstract
The effects of two pumpkin cultivars and five fungicide programs on cucurbit powdery mildew development and yield were evaluated in southern New Jersey from 2005 to 2007. Each year, five separate fungicide programs were applied to powdery mildew-tolerant cv. Magic Lantern or powdery mildew-susceptible cv. Howden pumpkin. The five fungicide programs applied season-long (10 applications per program) included: 1) protectant fungicides only: manzate + sulfur [Fungicide Resistance Action Committee (FRAC) codes M3 + M2] alternated weekly with maneb + copper hydroxide (FRAC codes M3 + M1); 2) standard program: chlorothalonil + myclobutanil (FRAC codes M5 + 3) alternated with azoxystrobin (FRAC code 11); 3) intensive program: maneb + myclobutanil (FRAC codes M3 + 3) alternated with [famoxadone + cymoxanil] (FRAC codes 11 + 27); 4) FRAC code 3 weekly: chlorothalonil + myclobutanil (FRAC codes M5 + 3) alternated with myclobutanil (FRAC code 3); and 5) FRAC code 11 weekly: chlorothalonil + azoxystrobin (FRAC codes M5 + 11) alternated with azoxystrobin (FRAC code 11). In each year, there were no significant interactions between the fungicide program and cultivar. In each year, area under disease progress curve values were highest when a FRAC code 11 fungicide was applied weekly compared with a FRAC code 11 fungicide applied in a weekly rotation with a FRAC code 3 fungicide or a FRAC code 3 fungicide applied weekly. Visual examination of leaves at the end of each production season revealed there were no significant differences in powdery mildew development on the top (adaxial) or bottom (abaxial) sides of leaves in untreated subplots. Powdery mildew development was lower on the bottom sides of leaves when a Fungicide Resistance Action Committee (FRAC) code 3 fungicide was applied weekly compared with a FRAC code 11 fungicide applied weekly or when a FRAC code 3 fungicide was rotated weekly with a FRAC code 11 fungicide in each year of the study. There were no significant differences in total number of harvested fruit, number of harvested orange fruit, average weight of orange fruit, or percentage of harvested orange fruit between fungicide programs in each year of the study. Results of this study, based on arcsine-transformed area under disease progress curve (AUDPC) values and top and bottom leaf surface ratings, suggest that the weekly use of the FRAC code 11 fungicide lead to the development of practical resistance in the field population of cucurbit powdery mildew. Rotating a FRAC code 11 and FRAC code 3 fungicide weekly resulted in lower AUDPC values and powdery mildew development on the bottom side of leaves in 2 of 3 years of this study. However, based on AUPDC values and leaf rating values, the level of control obtained with the high-risk FRAC code 3 fungicide was less during each consecutive year. The immediate erosion of control (i.e., qualitative resistance) as observed with the FRAC code 11 fungicide or the gradual decline of control (quantitative resistance) as observed with the FRAC code 3 fungicide over three growing seasons shows the importance of being able to detect and understand the mechanisms of practical resistance development. This understanding will allow appropriate fungicide control recommendations to be made in a timely (i.e., real-time) manner. Importantly, fungicide resistance is most likely to develop on the bottom side (abaxial) of pumpkin leaves when effective, low-risk (nonmobile) fungicides (FRAC code M numbers) are tank-mixed with high-risk fungicides in cucurbit powdery mildew control programs. Tank-mixing fungicides that have a high risk for resistance development with protectant fungicides that have a low risk for resistance development remains critically important when controlling cucurbit powdery mildew and reducing the potential for fungicide resistance development. This is the first report of cucurbit powdery mildew developing practical resistance to a FRAC code 11 and FRAC code 3 fungicide in New Jersey.
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Claims 13
Claim · model-written summary
Area under the disease progress curve is highest when a FRAC code 11 fungicide is applied weekly, compared with a weekly rotation with a FRAC code 11 fungicide.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e0“The effects of two pumpkin cultivars and five fungicide programs on cucurbit powdery mildew development and yield were evaluated in southern New Jersey from 2005 to 2007”
e1“In each year, area under disease progress curve values were highest when a FRAC code 11 fungicide was applied weekly compared with a FRAC code 11 fungicide applied in a weekly rotation”
Claim · model-written summary
Weekly use of a FRAC code 3 fungicide reduces powdery mildew development on the bottom side of pumpkin leaves compared with a weekly FRAC code 11 fungicide.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e2“Powdery mildew development was lower on the bottom sides of leaves when a Fungicide Resistance Action Committee (FRAC) code 3 fungicide was applied weekly compared with a FRAC code 11 fungicide applied weekly”
Claim · model-written summary
Rotating a FRAC code 11 and a FRAC code 3 fungicide weekly lowers AUDPC values in pumpkin in 2 of 3 years.
- Taxon
- pumpkint0
- Treatment
- Rotating a FRAC code 11 and FRAC code 3 fungicide weeklye3
- Outcome
- AUDPC valuese3
- Direction
- lowere3
- Qualifier
- in 2 of 3 years of this studye3
Not reportedComparator
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e3“Rotating a FRAC code 11 and FRAC code 3 fungicide weekly resulted in lower AUDPC values and powdery mildew development on the bottom side of leaves in 2 of 3 years of this study”
Claim · model-written summary
Rotating a FRAC code 11 and a FRAC code 3 fungicide weekly lowers powdery mildew development on the bottom side of pumpkin leaves in 2 of 3 years.
- Taxon
- pumpkint0
- Treatment
- Rotating a FRAC code 11 and FRAC code 3 fungicide weeklye3
- Interactor
- Powdery mildewe3pathogen
- Outcome
- powdery mildew developmente3
- Direction
- lowere3
- Qualifier
- on the bottom side of leavese3
Not reportedComparator
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e3“Rotating a FRAC code 11 and FRAC code 3 fungicide weekly resulted in lower AUDPC values and powdery mildew development on the bottom side of leaves in 2 of 3 years of this study”
Claim · model-written summary
Powdery mildew development on the top and bottom leaf sides does not differ in untreated pumpkin subplots.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e4“Visual examination of leaves at the end of each production season revealed there were no significant differences in powdery mildew development on the top (adaxial) or bottom (abaxial) sides of leaves in untreated subplots”
Claim · model-written summary
Total number of harvested fruit, number of orange fruit and average orange fruit weight do not differ between fungicide programs in pumpkin.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e5“There were no significant differences in total number of harvested fruit, number of harvested orange fruit, average weight of orange fruit, or percentage of harvested orange fruit between fungicide programs in each year of the study”
Claim · model-written summary
The percentage of harvested orange fruit does not differ between fungicide programs in pumpkin.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e5“There were no significant differences in total number of harvested fruit, number of harvested orange fruit, average weight of orange fruit, or percentage of harvested orange fruit between fungicide programs in each year of the study”
Claim · model-written summary
The fungicide program and cultivar do not interact significantly for powdery mildew control in pumpkin.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e6“In each year, there were no significant interactions between the fungicide program and cultivar”
Claim · model-written summary
Weekly use of the FRAC code 11 fungicide may lead to practical resistance of the cucurbit powdery mildew field population.
- Taxon
- pumpkint0
- Treatment
- weekly use of the FRAC code 11 fungicidee7
- Interactor
- cucurbit powdery mildewe7pathogen
- Outcome
- practical resistancee7
Not reportedComparatorDirection
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e7“suggest that the weekly use of the FRAC code 11 fungicide lead to the development of practical resistance in the field population of cucurbit powdery mildew”
Claim · model-written summary
The high-risk FRAC code 3 fungicide gives less control of pumpkin powdery mildew in each consecutive year.
- Taxon
- pumpkint0
- Treatment
- high-risk FRAC code 3 fungicidee1
- Outcome
- level of controle1
- Direction
- lesse1
- Qualifier
- during each consecutive yeare1
Not reportedComparator
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e1“the level of control obtained with the high-risk FRAC code 3 fungicide was less during each consecutive year”
Claim · model-written summary
Cucurbit powdery mildew of pumpkin develops practical resistance to a FRAC code 11 and a FRAC code 3 fungicide in New Jersey.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e1“This is the first report of cucurbit powdery mildew developing practical resistance to a FRAC code 11 and FRAC code 3 fungicide in New Jersey”
Claim · model-written summary
Fungicide resistance is most likely to develop on the abaxial side of pumpkin leaves when low-risk fungicides are tank-mixed with high-risk fungicides.
- Taxon
- pumpkint0
- Treatment
- tank-mixed with high-risk fungicidese1
- Outcome
- fungicide resistancee1
- Qualifier
- on the bottom side (abaxial) of pumpkin leavese1
Not reportedDirection
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e1“fungicide resistance is most likely to develop on the bottom side (abaxial) of pumpkin leaves when effective, low-risk (nonmobile) fungicides (FRAC code M numbers) are tank-mixed with high-risk fungicides”
Claim · model-written summary
Tank-mixing high-risk with low-risk protectant fungicides remains critically important for reducing fungicide resistance development in pumpkin.
Verbatim
t0“Cucurbit Powdery Mildew of Pumpkin”
e1“Tank-mixing fungicides that have a high risk for resistance development with protectant fungicides that have a low risk for resistance development remains critically important when controlling cucurbit powdery mildew and reducing the potential for fungicide resistance development”
The same questions in other papers
fungicide · control · Cucurbita (pumpkins)Positive and negative results
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- positive
- positive
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fungicide · disease · Cucurbita (pumpkins)Positive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- positive
7 papers more in this group
See all 11 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.