Mitigating Almond Hull Rot
Post-bloom nutrition in almonds occurs rapidly in order to satisfy nut-fill. Soil and tissue analyses should show the trees are adequately fed and have the available nutrients to carry them through harvest. However, most orchards still face many challenges including, but not limited to, biotic and abiotic stressors.
Having an Almond Wise program in place will help ensure your orchard is ready for maximum production, and your Helena consultant will provide the right tools to support you throughout the growing season.
The importance of nitrogen in plant function is well known as it is a major component of amino acid and chlorophyll production. It has been well established that high rates of applied nitrogen in almonds have a large impact on increasing hull rot incidence. A very common mold found in soil, Rhizopus stolonifer, settles on the tree throughout the season and feeds on excess nitrogen that accumulates in the hull during hull split. This process creates a toxic metabolite known as fumaric acid that damages the spur, eventually affecting the fruit attached to the shoot. This process results in the propensity of dead shoots and limbs, which will reduce yield in future growing seasons.
Over the years, the University of California Cooperative Extension (UCCE) has studied the benefits of incorporating different cultural practices to mitigate the damaging effect of almond hull rot, including deficit irrigation, minimizing nitrogen application near hull split, and applying bioscience products.
Utilize PK is a 0-3-2 foliar nutrient system that boosts plant performance by improving nutrient uptake at key reproductive stages in plant development. Research shows Utilize PK boosts the production of nitrate reductase. Nitrate reductase is used in the process of converting nitrate-nitrogen into plant-available forms, making this vital process more efficient in the utilization of nitrogen. Utilize PK supports balanced nitrogen levels in your almond crop to help reduce the number of almond hull rot strikes per tree.
Utilize PK, timed with Troubadour insecticide (methoxyfenozide) for Navel Orange Worm in late June and July hull split applications, may significantly reduce hull rot (see graph). This approach supports UCCE recommended cultural practices for managing tree vigor, and as a result, yield and quality can be enhanced.
To create an Almond Wise program and learn more about Utilize PK, contact your local Helena representative.
- James Schaeffer, Western Division Product Specialist