Impact of azoxystrobin, dimethomorph, fluazinam, fosetyl-Al, and metalaxyl on growth, sporulation, and zoospore cyst germination of three Phytophthora spp.

Michael E Matheron, M. Porchas

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83 Citations (Scopus)

Abstract

In vitro activity of azoxystrobin, dimethomorph, and fluazinam on growth, sporulation, and zoospore cyst germination of Phytophthora capsici, P. citrophthora, and P. parasitica was compared to that of fosetyl-Al and metalaxyl. The 50% effective concentration (EC50) values for inhibition of mycelial growth of the three pathogens usually were lowest for dimethomorph and metalaxyl, ranging from <0.1 to 0.38 μg/ml. However, the 90% effective concentration (EC90) levels for dimethomorph always were lower than the other four tested compounds, with values ranging from 0.32 to 1.6 μg/ml. Mycelial growth of P. capsici, P. citrophthora, and P parasitica was least affected by azoxystrobin and fluazinam, with estimated EC90 values >3,000 μg/ml. Reduction of sporangium formation by P. capsici, P. citrophthora, and P. parasitica in the presence of dimethomorph at 1 μg/ml was significantly greater than that recorded for the same concentration of azoxystrobin, fluazinam, and fosetyl-Al. For the three species of Phytophthora, zoospore motility was most sensitive to fluazinam (EC50 and EC90 values of <0.001 μg/ml) and least sensitive to fosetyl-Al, with EC50 and EC90 values ranging from 299 to 334 and 518 to 680 μg/ml, respectively. Germination of encysted zoospores of P. capsici, P. citrophthora, and P. parasitica was most sensitive to dimethomorph (EC50 and EC90 values ranging from 3.3 to 7.2 and 5.6 to 21 μg/ml, respectively), intermediate in sensitivity to fluazinam (EC50 and EC90 from 18 to 108 and 67 to >1,000 μg/ml, respectively) and metalaxyl (EC50 and EC90 from 32 to 280 and 49 to 529 μg/ml, respectively), and lowest in sensitivity to azoxystrobin and fosetyl-Al (EC50 and EC90 from 256 to >1,000 μg/ml). The activity of azoxystrobin, dimethomorph, and fluazinam on one or more stages of the life cycle of P. capsici, P. citrophthora, and P. parasitica suggests that these compounds potentially could provide Phytophthora spp. disease control comparable to that of the established fungicides fosetyl-Al and metalaxyl.

Original languageEnglish (US)
Pages (from-to)454-458
Number of pages5
JournalPlant Disease
Volume84
Issue number4
StatePublished - Apr 2000

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fosetyl
metalaxyl
zoospores
Phytophthora
sporulation
Phytophthora capsici
germination
Phytophthora citrophthora
Phytophthora nicotianae var. parasitica
sporangia
growth retardation
fungicides
disease control
developmental stages
dimethomorph
azoxystrobin
pathogens

ASJC Scopus subject areas

  • Plant Science

Cite this

@article{48b78387f8404bc6a9a95224bae5ea40,
title = "Impact of azoxystrobin, dimethomorph, fluazinam, fosetyl-Al, and metalaxyl on growth, sporulation, and zoospore cyst germination of three Phytophthora spp.",
abstract = "In vitro activity of azoxystrobin, dimethomorph, and fluazinam on growth, sporulation, and zoospore cyst germination of Phytophthora capsici, P. citrophthora, and P. parasitica was compared to that of fosetyl-Al and metalaxyl. The 50{\%} effective concentration (EC50) values for inhibition of mycelial growth of the three pathogens usually were lowest for dimethomorph and metalaxyl, ranging from <0.1 to 0.38 μg/ml. However, the 90{\%} effective concentration (EC90) levels for dimethomorph always were lower than the other four tested compounds, with values ranging from 0.32 to 1.6 μg/ml. Mycelial growth of P. capsici, P. citrophthora, and P parasitica was least affected by azoxystrobin and fluazinam, with estimated EC90 values >3,000 μg/ml. Reduction of sporangium formation by P. capsici, P. citrophthora, and P. parasitica in the presence of dimethomorph at 1 μg/ml was significantly greater than that recorded for the same concentration of azoxystrobin, fluazinam, and fosetyl-Al. For the three species of Phytophthora, zoospore motility was most sensitive to fluazinam (EC50 and EC90 values of <0.001 μg/ml) and least sensitive to fosetyl-Al, with EC50 and EC90 values ranging from 299 to 334 and 518 to 680 μg/ml, respectively. Germination of encysted zoospores of P. capsici, P. citrophthora, and P. parasitica was most sensitive to dimethomorph (EC50 and EC90 values ranging from 3.3 to 7.2 and 5.6 to 21 μg/ml, respectively), intermediate in sensitivity to fluazinam (EC50 and EC90 from 18 to 108 and 67 to >1,000 μg/ml, respectively) and metalaxyl (EC50 and EC90 from 32 to 280 and 49 to 529 μg/ml, respectively), and lowest in sensitivity to azoxystrobin and fosetyl-Al (EC50 and EC90 from 256 to >1,000 μg/ml). The activity of azoxystrobin, dimethomorph, and fluazinam on one or more stages of the life cycle of P. capsici, P. citrophthora, and P. parasitica suggests that these compounds potentially could provide Phytophthora spp. disease control comparable to that of the established fungicides fosetyl-Al and metalaxyl.",
author = "Matheron, {Michael E} and M. Porchas",
year = "2000",
month = "4",
language = "English (US)",
volume = "84",
pages = "454--458",
journal = "Plant Disease",
issn = "0191-2917",
publisher = "American Phytopathological Society",
number = "4",

}

TY - JOUR

T1 - Impact of azoxystrobin, dimethomorph, fluazinam, fosetyl-Al, and metalaxyl on growth, sporulation, and zoospore cyst germination of three Phytophthora spp.

AU - Matheron, Michael E

AU - Porchas, M.

PY - 2000/4

Y1 - 2000/4

N2 - In vitro activity of azoxystrobin, dimethomorph, and fluazinam on growth, sporulation, and zoospore cyst germination of Phytophthora capsici, P. citrophthora, and P. parasitica was compared to that of fosetyl-Al and metalaxyl. The 50% effective concentration (EC50) values for inhibition of mycelial growth of the three pathogens usually were lowest for dimethomorph and metalaxyl, ranging from <0.1 to 0.38 μg/ml. However, the 90% effective concentration (EC90) levels for dimethomorph always were lower than the other four tested compounds, with values ranging from 0.32 to 1.6 μg/ml. Mycelial growth of P. capsici, P. citrophthora, and P parasitica was least affected by azoxystrobin and fluazinam, with estimated EC90 values >3,000 μg/ml. Reduction of sporangium formation by P. capsici, P. citrophthora, and P. parasitica in the presence of dimethomorph at 1 μg/ml was significantly greater than that recorded for the same concentration of azoxystrobin, fluazinam, and fosetyl-Al. For the three species of Phytophthora, zoospore motility was most sensitive to fluazinam (EC50 and EC90 values of <0.001 μg/ml) and least sensitive to fosetyl-Al, with EC50 and EC90 values ranging from 299 to 334 and 518 to 680 μg/ml, respectively. Germination of encysted zoospores of P. capsici, P. citrophthora, and P. parasitica was most sensitive to dimethomorph (EC50 and EC90 values ranging from 3.3 to 7.2 and 5.6 to 21 μg/ml, respectively), intermediate in sensitivity to fluazinam (EC50 and EC90 from 18 to 108 and 67 to >1,000 μg/ml, respectively) and metalaxyl (EC50 and EC90 from 32 to 280 and 49 to 529 μg/ml, respectively), and lowest in sensitivity to azoxystrobin and fosetyl-Al (EC50 and EC90 from 256 to >1,000 μg/ml). The activity of azoxystrobin, dimethomorph, and fluazinam on one or more stages of the life cycle of P. capsici, P. citrophthora, and P. parasitica suggests that these compounds potentially could provide Phytophthora spp. disease control comparable to that of the established fungicides fosetyl-Al and metalaxyl.

AB - In vitro activity of azoxystrobin, dimethomorph, and fluazinam on growth, sporulation, and zoospore cyst germination of Phytophthora capsici, P. citrophthora, and P. parasitica was compared to that of fosetyl-Al and metalaxyl. The 50% effective concentration (EC50) values for inhibition of mycelial growth of the three pathogens usually were lowest for dimethomorph and metalaxyl, ranging from <0.1 to 0.38 μg/ml. However, the 90% effective concentration (EC90) levels for dimethomorph always were lower than the other four tested compounds, with values ranging from 0.32 to 1.6 μg/ml. Mycelial growth of P. capsici, P. citrophthora, and P parasitica was least affected by azoxystrobin and fluazinam, with estimated EC90 values >3,000 μg/ml. Reduction of sporangium formation by P. capsici, P. citrophthora, and P. parasitica in the presence of dimethomorph at 1 μg/ml was significantly greater than that recorded for the same concentration of azoxystrobin, fluazinam, and fosetyl-Al. For the three species of Phytophthora, zoospore motility was most sensitive to fluazinam (EC50 and EC90 values of <0.001 μg/ml) and least sensitive to fosetyl-Al, with EC50 and EC90 values ranging from 299 to 334 and 518 to 680 μg/ml, respectively. Germination of encysted zoospores of P. capsici, P. citrophthora, and P. parasitica was most sensitive to dimethomorph (EC50 and EC90 values ranging from 3.3 to 7.2 and 5.6 to 21 μg/ml, respectively), intermediate in sensitivity to fluazinam (EC50 and EC90 from 18 to 108 and 67 to >1,000 μg/ml, respectively) and metalaxyl (EC50 and EC90 from 32 to 280 and 49 to 529 μg/ml, respectively), and lowest in sensitivity to azoxystrobin and fosetyl-Al (EC50 and EC90 from 256 to >1,000 μg/ml). The activity of azoxystrobin, dimethomorph, and fluazinam on one or more stages of the life cycle of P. capsici, P. citrophthora, and P. parasitica suggests that these compounds potentially could provide Phytophthora spp. disease control comparable to that of the established fungicides fosetyl-Al and metalaxyl.

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