Agriculture: Citrus Pest Management Guidelines

Treatment Timing for Key Diseases

Note: Not all indicated timings may be necessary for disease control.

Disease Spring root flush Fall root flush Oct./Nov. Jan./Feb. March 5 to 1 wk PHI
Alternaria rot1 0 0 0 0 0 1/2
Anthracnose2 0 0 0 0 0 3
Greasy spot2 0 0 0 0 0 3
Phytophthora brown rot 0 0 3 3 2 1
Phytophthora root rot 3 3 0 0 0 0
Rind disorder3 0 0 3 2 1 0
Septoria spot 0 0 3 3 1 0
Rating: 3 = most effective, 2 = moderately effective, 1 = least effective, and 0 = ineffective
1 Alternaria fruit rot management with fungicides is generally low (1) with preharvest fungicide applications before wet weather (the current understanding of the epidemiology of the disease is limited).
2 Anthracnose and greasy spot management is generally high (3) with preharvest applications before warm, wet weather.
3 Management of rind disorder especially on early-season mandarins (e.g., Satsuma) is generally high (3) provided that fruit are harvest within 6 to 8 weeks of color break. Other mid- and late-season cultivars have less problems unless high rainfall is observed. Treatment timing should be at color break. Repaeat applications may be necessary.

Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California. (PDF)

Text Updated: 03/22