Knowledgebase
Nectarine Spraying #891342
Asked January 07, 2025, 11:59 AM EST
Lane County Oregon
Expert Response
The pesticide to use is based on what you are trying to control. The two major issues for nectarines in this region are peach leaf curl and shothole fungus. Elemental sulfur is not effective in controlling either of those diseases. Lime sulfur is effective, but that is a different chemical and it is not available to home gardeners in Oregon. For home gardeners, your best options to control shothole and peach leaf curl are copper and chlorothalonil. Copper is effective against shothole but less so against peach leaf curl. Chlorothalonil helps manage both diseases. For peach leaf curl, two fungicide applications during the dormant season are recommended for western Oregon: one in late October/early November (at about 50% leaf fall), and the second just before bud swell (usually in late February, before the floral buds open). For shothole, you need to spray copper around Thanksgiving and again around Christmas.
Sulfur can be used to control brown rot in nectarines, but it isn't sprayed until just before harvest (i.e. it wouldn't be effective if you sprayed it now). Pyrethrins are typically used to control insect pests.
For more on controlling diseases in home orchards, including nectarines, refer to the following: https://extension.oregonstate.edu/catalog/pub/ec-631-managing-diseases-insects-home-orchards. This publication notes which pesticides are highly toxic to bees in Table 1. To reduce pesticide exposure to bees, don't spray while plants are in bloom, and spray in the evening or early morning hours when the bees are not actively foraging.
I hope that helps, but if you know what pest you are trying to control, I can give a more direct indication. I do recommend spraying for shothole and peach leaf curl since those diseases are so pervasive in peaches and nectarines in this region. If you need help identifying insect pests or diseases, you can send photos of symptoms to the Master Gardener Plant Clinic at <personal data hidden>. They can help you identify the pest and provide recommendations.
