The cause of curling may vary between the different trees. On stone fruits, especially peach, the culprit might be Peach Leaf Curl, a very common fungal disease that, when severe, can cause drastic defoliation and a weakening of the tree. On apples, aphid or leafhopper feeding on the underside of expanding leaves can cause leaf curling or distortion. Other overlapping infections and pests are also possible, as fruit trees are vulnerable to an array of issues that generally require pesticide intervention to prevent or suppress. Once symptoms manifest for most diseases and some pest issues, it's too late that season to treat for it, so preventative measures need to start at the very beginning of the growing season, if not sooner. For example, a fungicide spray in autumn, such as later this month, is typically needed to prevent issues with Peach Leaf Curl the following year. A second follow-up spray is sometimes still recommended for that disease. Each spray must be thorough, covering the entire canopy (or bare branches) from all sides, to be effective.

If you opt to use organic pesticides, be aware that they tend to cost more than conventional/synthetic versions, and also tend to need more frequent application to continue providing protection, since their residues degrade faster. For some conditions, there might not be an organic alternative, but resources like the Virginia Tech pest management guide for home fruit can help with presenting options.

Additional approaches to managing fruit organically overlap techniques recommended for non-organic methods. Sanitation is key, where fallen leaves are removed from below the trees, any fallen fruit is removed promptly (whether end-of-season bad fruits, extras, or those that fell during June drop), and any dead wood is pruned out once noticed. This helps to prevent those materials from harboring pests and diseases into the next season or year. Growing a diversity of flowering plants near the orchard can also help with certain issues (mainly pest outbreaks), since the beneficial insects like predatory wasps and beetles drawn to those blooms will be present to hunt pests in the fruit trees, suppressing their populations. It has an added benefit of supporting pollinators needed to ensure cross-pollination of fruits for a good harvest, though weather can impact that if it's cool and rainy during the flowering period of the fruit trees.

If you haven't already explored them, we recommend that you visit the web pages for each of the fruit types you're growing to learn about how best to care for the trees and what problems to expect and how to manage them, since the timing of intervention can be key to success. Related fruits with similar care and similar problems, like apples and pears, are grouped together.

Miri