Flowering has started in most varieties. If growers are planning to take petiole samples, these should be collected at 80% capfall (average across patch). Petiole test are a good way to gauge what the nutritional balance of the vine is. The tests are also good if a particular patch is showing signs of poor growth or other nutritional deficiencies.
Petiole sampling kits are available through most resellers, and CCW. As the end of flowering approaches in early varieties, this means certain products are having WHP restriction windows closing rapidly, especially botrytis controls.
If you had botrytis last vintage, spore carryover into a new season is more likely, hence consider your control options now before these windows close. In regard to botrytis sprays, the AWRI earlier in the season notified the industry that they were recommending prohibiting the use of CAPTAN on wine grapes for Vintage 2016, due to a change in MRL’s in some markets.
Many growers had used Captan for botrytis control in previous seasons. Always check with your winery or consult your spray diary in regard to chemical selection and WHP requirements before spraying.
Light Brown Apple moth has been detected in some vineyards. When monitoring LBAM consider the following thresholds prior to applying chemical control.
|LBAM lifecycle stage||How to monitor||When to monitor||Common threshold|
|Egg masses||Inspect the upper side of the expanded leaves on 100 shoots||Once the first leaves have expanded and throughout the season||3 viable egg masses per 100 shoots|
|Larvae on shoots||Inspect shoot tips and webbed together leaves on 100 shoots||Throughout the season||20 larvae on foliage per 100 shoots|
|Larvae in bunches||Inspect inflorescences and bunches on 100 shoots||From inflorescence development onwards||10 larvae within bunches per 100 shoots|