Last year field trials were conducted on Gold 3 vines to determine whether the application of Actigard, at recommended application rates, post-harvest could impact components of yield in the following season.
Winter bud numbers; flower numbers and type; and fruit size and shape were measured to identify potential impacts.
Trials also included application of Actigard at rates up to double label recommendation, and at a two-week interval between repeat applications, which is seven days short of the 21-day interval recommended on the product label.
Results showed a negligible impact on components of yield in the following season when Actigard was applied at the recommended rate immediately post-harvest and when reapplied to leaves of good photosynthetic capacity pre-leaf fall.
In three of the four trial sites there appeared to be a slight trend for a small reduction in the number of side flowers per cane following Actigard treatment.
Full details of the trial will be available on the KVH website shortly but in summary the results support recommendations outlined by Syngenta for autumn application of Actigard. These are as follows:
- Apply 200 g/ha of Actigard (plus copper) immediately post-harvest as a foliar spray. Ensure thorough coverage of canopy and leaf stalks.
- If canopy condition allows (ie leaves are still green) and infection risk remains high, reapply Actigard 21 days later to extend protection into the leaf-fall period.
- Do not apply Actigard to vines that are stressed due to drought, excessive moisture, cold weather or disease.
- Avoid risk of spray drift to unharvested fruit and clean sprayers thoroughly.
