When it comes to growing healthy, productive tree nuts, growers can face many obstacles throughout the season, including a variety of fungal diseases. Now is the crucial time for almond and walnut growers to ensure their disease management is up to par.
Come springtime, the first disease almond growers often face is almond scab, or Cladosporium carpophilum. Warm, wet weather makes for perfect conditions when dealing with diseases such as almond scab. Higher density plantings in almond orchards can prevent orchard floors from drying out during the day, making matters even worse.
A sign that disease may be present includes sporulating twig lesions. UPL recommends beginning treatment as early as possible by applying fungicide sprays that will help keep almond scab in check before it can cause defoliation and weaken almond trees, which could impact yield and crop quality later in the season.
Two other fungal diseases that are common this time of year are Alternaria leaf spot and rust. Alternaria leaf spot can evolve quickly, especially in early summer, defoliating trees in a few short weeks and causing almond crop potential to fall with each leaf. The disease typically begins as half-inch brown spots on almond leaves that turn black as fungus spores develop. If left untreated, trees begin to lose their leaves.
Tree nut orchards experiencing high humid conditions can also be at risk for rust. The disease can first appear in late spring or early summer, with small yellow spots on the upper surface of leaves and brown spores on the bottom. To combat both Alternaria leaf spot and rust, a fungicide should be applied preventively before the first signs of the disease.
Specifically in walnuts, growers and PCAs should keep an eye out for Botryosphaeria blight, also known as bot. It’s a fungal disease that can lead to deteriorated tree health and production loss. The fungi spreads by spores that germinate and enter the tree through open wounds or scars. The symptoms of bot can be difficult to identify, and its ability to rapidly spread from tree to tree make this disease especially harmful to your walnut crop. UPL recommends the use of a fungicide during May through August for suppression of bot.
From bot in walnuts to Alternaria leaf spot in almonds, growers can turn to PH-D® Fungicide to protect their orchards. PH-D (FRAC 19) is a broad-spectrum fungicide with a 0-day pre-harvest interval in tree nuts. A unique FRAC-19 biological fungicide, PH-D can be used early in the season as a preventative or later for disease knock-down. It serves as an excellent rotational tool and tank-mix partner.
For more information about PH-D and UPL’s other class-leading disease management solutions for tree nuts from UPL, click here.
