IFAS Extension
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.
|
Pesticide |
FRAC MOA1 |
Mature Trees Rate/Acre2 |
|---|---|---|
|
Copper fungicide |
M 01 |
Use label rate. |
|
Amistar Top4 |
11 + 3 |
15.4 fl oz. Do not apply more than 61.5 fl oz (0.8 lb azoxystrobin and 0.5 lb difenoconazole)/acre/year. Do not apply more than 0.5 lb a.i./acre/season of difenoconazole. Do not apply more than 1.5 lb a.i./acre/season of azoxystrobin. Do not apply more than 3 times at highest rate. Minimum retreatment interval is 7 days. |
|
Enable 2F4 |
3 |
8.0 fl oz. Do not apply more than 3 applications or 24 fl oz (0.38 lb a.i.)/acre/season. Minimum retreatment interval is 21 days. |
|
Gem 500 SC3 |
11 |
1.9–3.8 fl oz. Do not apply more than 15.2 fl oz/acre/season for all uses. Best applied with petroleum oil. Do not apply within 7 days of harvest. |
|
Headline SC3 |
11 |
12–15 fl oz. Do not apply more than 54 fl oz (0.88 lb a.i.)/acre/season for all uses. Best applied with petroleum oil. |
|
Pristine4 |
11 + 7 |
16–18.5 oz. No more than 74 oz/acre/season which is equivalent to 1.17 lb a.i./acre/season of boscalid and 0.592 lb a.i./acre/season of pyraclostrobin. Up to 0.88 lb a.i./acre/season of pyraclostrobin can be used. Minimum retreatment interval is 10 days. |
|
Quadris3 |
11 |
9.0–15.5 fl oz. Do not apply more than 90 fl oz (1.5 lb a.i.)/acre/season for all uses. Best applied with petroleum oil. Minimum retreatment interval is 7 days. |
|
1 Mode of action class for citrus pesticides from the Fungicide Resistance Action Committee (FRAC) 2025. Refer to chapter 4, “Pesticide Resistance and Resistance Management,” for more details. 2 Lower rates can be used on smaller trees. Do not use less than minimum label rate. 3 Do not use more than 4 applications of strobilurin fungicides/season. Do not make more than 2 sequential applications of strobilurin fungicides (FRAC MOA 11). 4 Do not make more than 4 applications of Pristine or Amistar Top/season. Do not make more than 2 sequential applications of Pristine or Amistar Top before alternating to a non-strobilurin, non-SDHI (FRAC MOA 7), non-DMI (FRAC MOA 3) fungicide. | ||
