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Development of a Fungicide-Based Management Strategy for Foliar Disease Caused by Phoma ligulicola in Tasmanian Pyrethrum Fields

Citation

Pethybridge, SJ and Hay, FS and Wilson, CR and Groom, T, Development of a Fungicide-Based Management Strategy for Foliar Disease Caused by Phoma ligulicola in Tasmanian Pyrethrum Fields, Plant Disease, 89, (10) pp. 1114-1120. ISSN 0191-2917 (2005) [Refereed Article]

DOI: doi:10.1094/PD-89-1114

Abstract

The efficacy of a range of fungicides were assessed under in vitro conditions in four field trials over three seasons for the management of ray blight of pyrethrum, caused by the fungus Phoma ligulicola in Tasmania. Fungicides belonging to the demethylation inhibitor group, including prochloraz, tebuconazole, difenoconazole, and cyproconazole, produced the most significant reduction in mycelial growth in vitro compared with unamended controls. Significant reductions in germination of conidia resulted from low concentrations of azoxystrobin. In the field, azoxystrobin (as Amistar) at a rate of 300 g of product/ha significantly decreased disease intensity and increased pyrethrin yield (kg/ha) in all seasons. Applications of either azoxystrobin or difenoconazole (as Score) at a rate of 250 ml of product/ha in early spring were the most effective, whereas no significant benefit was demonstrated from applications in autumn. Over all seasons, azoxystrobin applications resulted in double the weight of flowers produced compared with nontreated areas, whereas increases in pyrethrin content within the flowers were season and location specific. Application of azoxystrobin and chlorothalonil (as Bravo 720) at a rate of 1.4 liters of product/ha resulted in a 45 to 48% increase in flowers, reduced defoliation, and increased stem diameter. The weight of individual flowers and flower maturity was not significantly affected by fungicide application. These data provide the basis for cost-effective management of this disease. © 2005 The American Phytopathological Society.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Pathology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural Crops
Objective Field:Horticultural Crops not elsewhere classified
Author:Pethybridge, SJ (Dr Sarah Pethybridge)
Author:Hay, FS (Dr Frank Hay)
Author:Wilson, CR (Associate Professor Calum Wilson)
ID Code:30078
Year Published:2005
Web of Science® Times Cited:26
Deposited By:Agricultural Science
Deposited On:2005-08-01
Last Modified:2006-05-22
Downloads:0

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