Citrus greening (HLB) and canker are notifiable in many countries because they are untreatable once established — this is a crop where vector control and clean nursery stock are the entire disease programme.
- Grown in
- Nigeria, Ghana, Brazil, Spain, India, China
- Season
- Perennial, 3–5 years to bearing
- Soil & pH
- Well-drained sandy loam, pH 6.0–7.5
What to scout for on Citrus
- Asymmetric blotchy leaf mottling — citrus greening
- Raised corky lesions with yellow halos — citrus canker
- Sticky honeydew and sooty mould from psyllids and scale
- Zinc deficiency showing as small, upright, mottled leaves
Diseases that attack Citrus
Leaf Spot
Septoria, Cercospora, Alternaria spp.
Nitrogen Deficiency
Abiotic — nutrient stress
Aphid Infestation
Aphidoidea
Products you can buy for Citrus
Typical registered products for the diseases above, with active ingredient, mixing rate, spray interval and pre-harvest interval. Rotate FRAC/IRAC groups to avoid resistance.
Chlorothalonil 75% WP
Active ingredient: Chlorothalonil
- Dose:
- 2 g per litre (1.5–2 kg/ha)
- Interval:
- Every 7–10 days
- PHI:
- 7 days
Backbone protectant for Septoria and Cercospora leaf spots. Full leaf coverage, including undersides, is essential.
Mancozeb 80% WP
Active ingredient: Mancozeb
- Dose:
- 2.5 g per litre
- Interval:
- Every 7 days
- PHI:
- 7 days
Adds zinc and manganese nutrition alongside disease control.
Azoxystrobin 23% SC
Active ingredient: Azoxystrobin
- Dose:
- 1 ml per litre (500 ml/ha)
- Interval:
- Every 14 days, maximum 2 per season
- PHI:
- 3–7 days
Strong translaminar movement. Always tank-mix or alternate with a multi-site to protect the QoI group.
Copper hydroxide 77% WP
Active ingredient: Copper hydroxide
- Dose:
- 2 g per litre
- Interval:
- Every 10 days
- PHI:
- 1–3 days
Use when bacterial leaf spot cannot be ruled out — copper covers both bacterial and fungal spotting.
Insecticidal soap (potassium salts)
Active ingredient: Potassium salts of fatty acids
- Dose:
- 10–20 ml per litre
- Interval:
- Every 5–7 days until colonies collapse
- PHI:
- 0 days
Kills only on direct contact — spray leaf undersides and growing tips where aphids cluster.
Neem oil (azadirachtin 1500 ppm)
Active ingredient: Azadirachtin
- Dose:
- 3–5 ml per litre
- Interval:
- Every 7 days, 3 applications
- PHI:
- 0 days
Anti-feedant and growth regulator; safest option near harvest and around beneficial insects.
Doses shown are typical registered field rates. Always read the product label, confirm the product is registered for your crop and country, respect the pre-harvest interval (PHI), and wear the protective equipment the label specifies. PlantWatch AI provides agronomic guidance, not a legal spray recommendation.
Is your Citrus showing symptoms right now?
Photograph the leaf and PlantWatch AI will diagnose the disorder and prescribe the exact product, dose and spray interval to use next.
Diagnose a plant