Source: newsletter Proeftuin Randwijk 2022-09

Experience in recent years has shown that canopied cultivation is a good way to control fruit tree cancer in Kanzi to a great extent.

On the organic block, there are four rows of Kanzi under a canopy that is open only in January-February. The rest of the time, the canopy is closed, with the trees getting wet only by splashing water. This canopy was realised in cooperation with Fruitmasters. So far, a limited number of trees have fallen out due to fruit tree canker, but the vast majority of these were due to canker on the trunk, most likely brought from the nursery. These trees are sprayed with sulphur a limited number of times annually and are otherwise fungicide-free. Also in the WUR plot of canopied cultivation, fruit tree canker is not a problem so far. Here, too, sulphur is sprayed only a few times a year and no fungicides are otherwise used.

Productivity is remarkably good for Elstar, Kanzi and Tessa. With pears, there do appear to be more challenges in a canopied cultivation where the trees are still regularly wet by splashing water.  

The very robust Cravo canopy proves to be a good canopy for year-round over the trees, and it opens and closes depending on rainfall or dewy conditions. However, this canopy will be far too expensive to serve as a canopy for an economically viable fruit crop.


By the 4th year, the canopy above the organic plot already has a lot of damage to the upper deck and this will have to be replaced. In fact, this lifespan is too short to ensure a financially covering story. However, the first commitment of this trial was to see what impact canopy growing has on organic fruit growing. In this area at least, we have become much wiser. Indeed, it turns out that covered cropping can very much reduce infestation by scab, fruit tree canker and storage rot. On the other hand, challenges remain, especially in the form of mildew and blood lice. It should be noted, however, that the problems with blood lice are limited this year because of the high level of parasitisation.


Given the positive effects of the canopy on preventing fruit tree canker and the fact that over the years, it has been observed that picking wounds are the most susceptible to fruit tree canker, a new trial has been set up this year in collaboration with EFC, in which the trees are canopied with a Fruitsecurity Powerflex system from shortly before to a few weeks after harvest. Here, the trees are normally just under a hail net and shortly before picking, the rain canopy is closed. This is similar to the system used in cherries.

The idea is to keep the picking wounds dry, but also to prune most of the trees already a few weeks after flowering. This will also keep the picking wounds dry and the canopy can be opened again a few weeks after pruning. This is expected to greatly reduce the number of canker infections and hopefully keep the trees virtually free of fruit tree cankers. This could be a change in growing method, keeping the canopy system affordable but sufficiently robust to stand for a large number of years.



In addition, the apples are simply outside for much of the year, building up their normal sugars etc. Hopefully, this approach could provide solace to move to a 15-18 year lifespan at Kanzi too and be ready for the reduced availability of resources coming our way.



This video shows the project from start to finish. 

Wondering if we can do something for you?

Mail or call us for the possibilities!