No abstract

New Zealand pipfruit crops require postharvest fungicides for control of European canker, caused by Neonectria ditissima. Fungicide efficacy trials to protect leaf scars from N. ditissima infections were conducted during autumn 2013 and 2014. Disease control of artificially inoculated leaf scars was achieved by single applications of copper oxychloride and copper oxide, but not copper hydroxide, applied at 4.3, 1.1 and 0.6 kg elemental copper/ ha respectively. Control of leaf scar infections by copper oxide (0.65 and 0.95 kg elemental copper/ha) was similar to control by captan. Leaf scars (0-10 days old) remained susceptible to infections up to 10 days after leaf fall; disease control was achieved by re-distribution of copper and captan fungicides onto new leaf scars. Disease control using copper oxide was consistent and similar to control using captan. The copper product, and concentration of elemental copper, are important for successful control of leaf scar infections by N. ditissima.

With a fast change of land use in Marlborough from extensive pastoral farming to intensive irrigated viticulture, a need has risen to investigate the sustainable use of the available water. In 2001 a 5 ha irrigation research project was installed in a Marlborough Sauvignon Blanc vineyard. Irrigation treatments installed were control (compensate 100% for crop evapotranspiration (ET(O)), 80%, 70% and 60% of ET(O). During the two years that the Regulated Deficit Irrigation (RDI) trial has run so far, very different climatic conditions created much greater differences in yield and vegetative growth, than up to 40% reduction in irrigation, none of which were significant. The use of sap flow in the vines has been fine-tuned and is now giving reliable results on which to base vine water need.

Postharvest foliar nitrogen (urea) is often applied to apple leaves immediately after picking for bud fertilising and/or during leaf fall for Venturia inaequalis control During 20132016 ethylene diamine tetraacetic acid copper (EDTACu to enhance leaf abscission) urea calcium nitrate and BudWiser foliar treatments were applied alone or in combination to determine their effects on leaf scar infection by Neonectria ditissima in Braeburn (201314) Scifresh and Royal Gala (201516) orchards In 201314 leaf scar infection increased sixfold when 5 urea was added to EDTACu and sprayed at the onset of leaf fall In 201516 up to a ninefold increase in leaf scar infections was observed The timing of application was more important than the amount or form of nitrogen used As a result of this research the use of ureabased foliar nitrogen fertilisers for V inaequalis before leaf fall are not recommended and growers should consider all factors affecting Neonectria ditissima infections before applying nitrogen immediately after harvest

No abstract