Articles
PRELIMINARY STUDIES TOWARD MANAGING WALNUT BLIGHT IN TASMANIA, AUSTRALIA
Article number
705_66
Pages
451 – 456
Language
English
Abstract
Walnut blight, caused by Xanthomonas campestris pathovar juglandis, is responsible for significant crop loss in early leafing varieties of walnut in Tasmania.
Research was undertaken to establish the efficacy of copper-based and non copper-based products on walnut blight in Tasmania.
Copper-based products were more effective than non copper-based products in reducing blight incidence and yield loss.
The most effective product was Mankocide®: multiple applications at 0.5 kg/100 L with 1000 L/ha water reduced mean blight incidence of fruits to less than 12%. Applied at 3000 L/ha water mean blight incidence was 3%. In the 2002-2003 season Bordeaux mixture delayed until three weeks after 5% terminal bud burst had 32% mean blight incidence, significantly more than if Bordeaux was initially applied at bud burst or at two weeks after bud burst (12% and 14%, respectively). The timing of initial application of Mankocide® in the 2003-2004 season had no effect on the mean blight incidence.
The severity of disease on fruits at final nut size appeared to affect the number of nuts that were harvested.
Addition of an organosilicone penetrant, Pulse®, to bactericides appeared to reduce mean blight incidence when applied weekly for 4 weeks after terminal bud burst.
Further research is required to determine the critical environmental factors that influence the development of the disease under Tasmanian conditions.
Research was undertaken to establish the efficacy of copper-based and non copper-based products on walnut blight in Tasmania.
Copper-based products were more effective than non copper-based products in reducing blight incidence and yield loss.
The most effective product was Mankocide®: multiple applications at 0.5 kg/100 L with 1000 L/ha water reduced mean blight incidence of fruits to less than 12%. Applied at 3000 L/ha water mean blight incidence was 3%. In the 2002-2003 season Bordeaux mixture delayed until three weeks after 5% terminal bud burst had 32% mean blight incidence, significantly more than if Bordeaux was initially applied at bud burst or at two weeks after bud burst (12% and 14%, respectively). The timing of initial application of Mankocide® in the 2003-2004 season had no effect on the mean blight incidence.
The severity of disease on fruits at final nut size appeared to affect the number of nuts that were harvested.
Addition of an organosilicone penetrant, Pulse®, to bactericides appeared to reduce mean blight incidence when applied weekly for 4 weeks after terminal bud burst.
Further research is required to determine the critical environmental factors that influence the development of the disease under Tasmanian conditions.
Publication
Authors
M.D. Lang, J.L. Hills, K.J. Evans
Keywords
copper, spray timing, fruit fall, Xanthomonas campestris pathovar juglandis
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