Explore expert recommendations for scouting for and treating black spot in Florida citrus groves.
Black spot may not be a major concern for the majority of Florida citrus growers. It has thankfully been mostly confined to southwest Florida since being discovered 12 years ago. Researchers believe this is due to dry conditions in spring and early summer, but a slow northward movement has been observed. Because of this, it’s important for citrus growers to continually scout for the symptoms and understand the recommendations for treating black spot. A UF/IFAS Tip of the Week shares tips on spotting and combating black spot in Florida citrus groves. See the tips below.
Tips for Scouting and Treating Black Spot
According to the article, citrus growers should look for:
- “The most easily identifiable and diagnostic symptom is hard spot on ripe fruit…” and are “small (3/16 to 1/8 inch), round and slightly depressed with brick red to dark chocolate brown edges.”
- “There are very few symptoms on leaves.”
- “The disease is most frequently seen first on declining trees. The late-hanging cultivars, like Valencia, are the most susceptible in Florida.”
- “Growers need to look at five to six areas within a 10-acre block to have a reasonable idea of the extent of the disease.”
In terms of treating black spot, recommendations include:
- “If there are many diseased trees in an area, a leaf litter treatment should be considered.”
- “Growers have reported good disease suppression using compost to cover the herbicide strip where much of the leaf litter is found.”
- “compost accelerator Soil Set (1.3 fluid ounces/acre) applied via herbicide boom at 50 gallons per acre on the 10-foot herbicide strip reduced the amount of disease and the number of diseased fruits…in March to April.”
- “Leaf litter amendments…should be paired with a fungicide program” from “May through September with monthly applications.”
Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions or concerns about your farm or pasture, contact us and one of our team will be in touch.