Richard Mills, Summerfruit NZ Technical Advisor
We are all but done and dusted for the 2021-22 season. There is little stone fruit still on supermarket shelves and at reasonably high retail price but all in all that’s it.
The lasting memories of this season are of lower volumes, higher prices and more rain than desired in December, February and March. But in general it was considered an “okay” season. Just. It was not often that the fruit received the ultimate consumer accolade of yum, even the home-grown tree ripe fruit, but mostly acceptable.
What has got me thinking is the amount of probable inoculum in the mummified fruit that is in the trees or on the ground. A couple of seasons ago Summerfruit NZ put together a wall chart, the ‘brown rot action plan’ with a recommendation for on orchard autumn work to ‘destroy mummies from ground and tree’. I can’t help but think that this will be so much more important this year given the wet season that we have had. The standard recommendation is to bury (which seems unlikely) or burn the fruit and stones that are remaining. This this too seems unlikely from a practical sense, especially when I look at the amount of fruit under some trees.
If the essence is to have a clean and hygienic orchard before next spring, we need to have those stones well decomposed. Raking them into the grass sward and smashing them to tiny little pieces seems like a good option – and the sooner the better to give maximum time for decomposition. There was some work done by Plant & Food Research on cherry stones in Central Otago looking at botrytis control which resulted in near 100% efficacy when the pits were out in the grassed area compared to directly under the trees. I’m picking that this area has a better microbiological life than the herbicide strip. I can’t see why this same idea wouldn’t work for brown rot control. Weedy herbicide strips are going to make this task challenging but it does need to be done.
I would encourage having this type of conversation with the orchardist across the fence as well as the home growers nearby. Anything to lower the inoculum level in your area before spring seems like a really good scheme. I’m sure the spray reps will be keen to chat about proprietary products that might be helpful in this space as well.
If you think that there were sufficient fungicides applied but the result was still poor, it might be time for a resistance test to be done. These are not cheap but neither is crop failure. If you are interested give me a call and we’ll work though the process together. If we can send a group of samples away together this is more efficient for the lab and cost effective for the growers.
Changing subject slightly Summerfruit NZ needs to collect and collate the data from Summerfruit spray diaries from this season just gone. The data once collated is anonymised and used to provide information in response to many queries that come from various regulatory bodies and government agencies such as MPI. With this information we can track trends, respond to proposals to limit use and decide as an industry what research to fund. Please send your spray diaries to firstname.lastname@example.org in whatever form you have them, preferably electronic and we will add them to the collated data.
Please put aside the afternoon of 10th May for a SummerGreen winter technical meeting at the function centre in Havelock North. It is planned to run from 2-5pm (final details will be confirmed closer to the date) and we plan to include a networking session over some refreshments after the meeting.
Summerfruit Technical Advisor