UF/IFAS Citrus Research

Disease Management

Citrus canker

Windbreaks are an effective protective measure for fresh fruit.
Monitor foliage for early season lesions.
Consider an early season (March) application for fresh fruit.
Keep leafminer suppressed on foliage.
Copper is still best chemistry to suppress canker.
SAR activation provides additional protection from canker when combined with copper.
Oxytetracycline injections do not reduce canker.

Phytophthora root rot

When planning a planting, learn phytophthora history of site.
Good grove drainage is important to reduce pooling water.
Select tolerant rootstocks like Swingle or others with a known Phytophthora-tolerant profile.
Plant clean nursery stock and reject visibly damaged trees.
Plant bud union at least 6 inches above soil line.
Diaprepes root weevil and fire ant control are important.
Phytophthora root rot can lead to brown rot in early season cultivars.
Huanglongbing makes trees more susceptible to phytophthora root rot but fungicides less effective.
Oomycete specific fungicide applications are recommended if the number of propagules detected in a composite sample is above 10 to 20 propagules per cm³ of soil.