Continue on with your protective spray program, paying particular attention to Powdery Mildew. Thorough coverage and timing early in the season is critical in preventing disease outbreaks later.
Flowering has now commenced which means some products are almost at the time when they can no longer be used, especially Botrytis controls. With the very wet start to spring, and some predictions of continuing wet weather in the year (or if you had botrytis last vintage) spore loads are more likely to be higher, hence consider your control options now before these treatment windows close.
Also, keep an eye out for Light Brown Apple Moth (LBAM) in developing bunches. Look for the little web and curling structures that may indicate LBAM is present. If enough of the pest is detected, it may warrant a control. For more information on LBAM, please refer to the Factsheet.
Water management must also be a focus, with growth stages approaching fruit set. Renowned scientist and educator Peter Dry, in his presentation and discussion with Riverland growers a couple of years ago, was very forthright in co-relating increased fruit quality in red varieties with planned, measured, controlled levels of vine stress in the immediate post fruit set period – without significantly compromising cropping levels. A mild level of stress post fruit set for a few weeks helps the vines switch their growth cycle from ‘vegetative’ into ‘fruit development and ripening’.
Consider the amount of water and nutrition applied in terms of vine vigour. Many growers have been struggling to apply planned fertiliser applications given the low irrigation requirements this year with the cooler/wetter season. Vine vigour has been slow to get going but a few warm days will really kick the vines into gear. Be mindful that most fertiliser applications that will affect the current crop need to be applied by flowering. Post flowering applications can lead to excessive vigour which may need to be trimmed off later, especially if disease outbreaks occur. If you haven’t got all your intended fertiliser out as planned, don’t worry; just bank it in the shed until the critical post-harvest window.