In kiwifruit, the target for disease control is petals that adhere to the fruit, aborted fruitlets and decaying leaf / vine material. Applications should be made at flowering for Sclerotinia and Botrytis control. BOTRY-Zen® currently has a Limited Claim for Psa – Not Fully Proven. Applications to control Psa should be made from bud-burst to fruit-set, after harvest prior to leaf-drop and again at pruning. The targeted timing after harvest is to establish BOTRY-Zen® on the nutrient source that Psa, Sclerotinia and Botrytis can grow on and to try and reduce the amount of disease infecting the crop in the following season. At flowering BOTRY-Zen® controls disease development, significantly reducing fruit scarring.
Season 2017 / 18
After last seasons indifferent conditions in the Bay (and around the country as well), kiwifruit growers were hoping for a better year in the 2017/18 season. So far the start of the season has seen some warm patches with periods of rain. The climate boys have said there is a possibility of a change in the weather pattern to La Nina over the Christmas break, which could bring some higher rainfall and warmer temperatures to the North Island. After the Christmas break the El Nino pattern will return and continue. So this could be a mixed bag for this season.
Whatever your thoughts are, protect your crop from Sclerotinia and Psa with BOTRY-Zen. Earlier applications will see you through this part of the season with a proven non toxic, nil residues, no resistance problems and no safety issues with the spray applicator.
Sclerotinia and Botrytis disease levels are controlled with BOTRY-Zen® applications at flowering. BOTRY-Zen® excludes Sclerotinia and Botrytis colonisation and significantly reduces the scarring caused by Sclerotinia and the amount of Botrytis inoculum in the canopy.
In October 2013, after the good results from last seasons’ field trials, Botryzen (2010) Ltd applied to update its registration to include a Limited Claim for Psa – Not Fully Proven. This has been granted by the ACVM. Applications for Psa are recommended from bud-burst to fruit-set, and then again after harvest and at pruning.
In May 2014 BOTRY-Zen® was officially added to the KVH/Zespri spray charts for ‘Post Harvest’ usage in controlling Psa in Kiwifruit. On the recommended Product list it states:
“Apply post-harvest through dormancy. Should not be applied when fruit is on the vines as it can cause staining. Certified Bio Gro Status. This product is available for Psa-V control on orchards that have completed harvest”.
Trial conducted by Plant and Food Research
Percentage incidence of fruit scarring due to Sclerotinia on kiwifruit vines sprayed with Rovral® FLO and BOTRY-Zen® in two orchards assessed in December 2005. Bars are standard error of the mean.
Two applications of BOTRY-Zen® at flowering (30% and 90% flowering) significantly reduced fruit scarring to a similar level as that of Rovral® FLO (one application at 90% flowering and a second application 3 weeks later).
Table 1 shows that two applications of BOTRY-Zen® significantly reduces Botrytis stem-end rot at harvest. BOTRY-Zen® reduces the amount of Botrytis on the adhering flower petals at flowering and then reduces the incidence of Botrytis on dead leaves or leaves with necrosis – resulting in fewer Botrytis spores within the canopy, able to colonise the fruit at harvest.
BOTRY-Zen® and ARMOUR-Zen® have both been included in the product testing programme being carried out by Kiwi Vine Health in their bid to control Pseudomonas syringae pv. actinidiae (Psa).