Find out what the latest citrus disorder is—greasy green—and how to manage it in your Florida citrus grove.
“A citrus disorder called greasy green has plagued Florida grapefruit producers for several years, causing a significant reduction in profits,” shared a Citrus Industry article. It’s “a disorder where fruit, particularly grapefruit, remain green despite degreening treatments. It occurs early in the season — in November or December — and causes fresh fruit growers and packers losses of from $20,000 to $1.7 million a year,” according to the article. See the signs and management options from the publication, which shares the highlights UF/IFAS Associate Professor and Extension Specialist, Megan Dewdney, shared at the Citrus & Specialty Crop Expo in August, below.
What is Greasy Green?
Dewdney shared that “The suspected cause of greasy green is the same fungus that causes greasy spot/rind blotch” due to “suspected fungicide resistance.” Scouting includes looking for symptoms that “resemble greasy spot/rind blotch on fruit and start early in the season,” but there are no symptoms “observed on leaves.”
Unfortunately, it “cannot be resolved with post-harvest measures and needs to be managed in the grove.”
Management for Greasy Green
Dewdney shared the following management tips:
- A greasy spot program should be a priority.
- Full coverage of the canopy is important, particularly the underside of leaves.
- Slow tractor and increase water.
- Copper rates adequate for canker suppression may not be enough for greasy green/greasy spot.
- Increase rates in May and June.
- Copper can cause burn in high May temperatures (> 94°F).
- Timing may need to shift to earlier in May.
- Ensure fungicide programs are not relying on a single mode of action.
- Rotation is very important.
- An August application may be needed in difficult blocks.
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.