Some factors affecting the pathogenicity of Alternaria alternata against the weed Rumex dentatus

Issue Date

9-2009

Abstract

Rumex dentatus L. is a problematic weed of wheat. Recently Alternaria alternata has been reported as a new pathogen on this weed, resulting in up to 70% mortality of the host plant. This study was conducted to optimize the conditions to maximize the potential of the pathogen for use as a mycoherbicide agent for the management of R. dentatus. Thus, the effect of spore concentration (10³, 105 and 107conidia mL-¹), host-plant growth stage (2–3 leaf, 4–5 leaf and 10–12 leaf or flowering stage), dew period (100% humidity for 12, 18 and 24 h) and temperature (20, 25 and 30 °C) on the pathogenicity of A. alternata was investigated. To further enhance the disease potential of the pathogens, different formulations of infected propagules [1 & 2% Gelatin, 1 & 2% carboxymethylcellulose (CMC), 1:1 Gelatin and CMC, 10 & 20% canola oil emulsion] were also used. The pathogenicity of A. alternata increased with increasing spore concentration and length of dew period. A spore concentration of 107 conidia mLˉ1 in 20% canola oil emulsion under 100% relative humidity for 24 h resulted in 100% mortality of R. dentatus plants at the 2–3 and the 4–5 leaf stages. Infection and mortality in mature plants at the 10–12 leaf stage was lower. The maximum mortality of the host plant was observed at 25 ºC and 30 ºC.

Source or Periodical Title

Philippine Agricultural Scientist, The (Formerly: The Philippine Agriculturist)

ISSN

0031-7454

Volume

92

Issue

3

Page

282-289

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Frequency

quarterly

Physical Description

graphs, table, references

Language

English

Subject

Alternaria alternata, canola oil emulsion, carboxymethylcellulose, dew period, gelatin, mycoherbicide, Rumex dentatus

En – AGROVOC descriptors

ALTERNARIA ALTERNATA; RUMEX; PATHOGENICITY; BIOLOGICAL WEED CONTROL; DEW POINT; CARBOXYMETHYLCELLULOSE

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