Application Timing Recommendations
- Citrus black spot is a quarantine disease. See booklet 1 for a detailed outline of regulations for growers, caretakers, harvesters, and haulers.
- Applications from early May to mid-September are recommended.
- Applications should be at least monthly.
- If April is wetter than average, an application in mid-April is advised.
- Strobilurin (FRAC MOA 11) resistance has been reported in other countries, so follow careful rotations with other modes of action and never use more than 2 strobilurin-containing fungicides twice in a row.
- Recommended to reserve strobilurin fungicides for the beginning of the season or when phytotoxicity from copper is likely.
- Other countries have found that strobilurin fungicides work better with petroleum oil.
- All fungicides other than copper recommended in Table 1 have similar efficacy in Florida. Copper is less effective but a good choice for the end of the season.
- Use the Citrus Copper Application Scheduler to time copper applications most efficiently.
- Use fungicides in conjunction with accelerated leaf litter decomposition.
Web Addresses for Links
Citrus Copper Application Scheduler: http://agroclimate.org/tools/citrus-copper-application-scheduler/
UF/IFAS publication PP289, “A Web-Based Tool for Timing Copper Applications in Florida Citrus”: https://doi.org/10.32473/edis-pp289-2012
Recommended Chemical Controls
READ THE LABEL.
See Table 1.
Rates for pesticides are given as the maximum amount required to treat mature citrus trees unless otherwise noted. To treat smaller trees with commercial application equipment including handguns, mix the per-acre rate for mature trees in 250 gal of water. Calibrate and arrange nozzles to deliver thorough distribution and treat as many acres as this volume of spray allows.
Table 1. Recommended chemical controls for citrus black spot.