Post-harvest care crucial for next season

As we head into peak harvest season for key crops like apples and kiwifruit, the Farmlands Horticulture team have a clear message: don’t get complacent once the fruit is picked. There are two main components to the post-harvest programme growers need to get right. The first is around looking after plants during leaf fall, when they are at heightened risk of bacterial infections such as PSA in kiwifruit and fungal infections such as European Canker in apples. “Every time a leaf falls off, you have an open wound, like when we get a cut that can get infected,” explains Andy Davis, Farmlands Technical Manager – Horticulture.

“Different plants are susceptible to different bacteria and fungi, but the fundamentals of all control methods at this time are the same: you're covering leaf scars with a suitable fungicide to protect them against infection.” Bacterial infections in plants can range from nuisance value to being fatal for plants, says Graeme Lee, Farmlands Regional Manager – Horticulture.

“For apples, pears and summer fruit, especially cherries, they have either fire blight or blast, which can significantly impact tree health. PSA in kiwifruit will kill vines. That's the extreme end of it,” Graeme says. “PSA can severely reduce yield, vine health, and orchard longevity. It causes leaf function to go right out the window. You've got leaves that are breaking down and canes that will die. It's not good in any way, shape or form.”

The right nutrients

The second, often neglected, aspect of post-harvest care is around plant nutrition, and making sure plants have the right nutrients before they go dormant over winter. “It’s setting yourself up for the following year,” Graeme says. “With kiwifruit, we're putting some nutrients into the vine before the plant does shut down, so that we have the right reserves to support flowering, pollination, and fruit set.”

Despite the importance of the postharvest programme, it is not always easy to get the job done. Andy says pressure on labour and harvesting fruit make it a difficult time for growers to priotise post-harvest spraying. “Usually they are worn out and over it by the end of harvest, so it doesn’t always get done. It also requires a resource, and you've got to plan for it,” he says. “It requires somebody on a tractor, and it is a struggle sometimes to make this happen, but it is crucial to make sure there is the resource available to get this important job done.”

The value of post-harvest nutrition has often been debated, Andy says. “However, there has been a lot of research showing its benefits around bud strength and things like flower initiation,” he says. “Trees and vines operate on stored reserves during the early growth, and when plants fire up in the spring, key nutrients like nitrogen help sustain the plant as it gets back up and running.”