The most disease-prone crop most growers ever plant. Tomato hosts fungal, bacterial, viral and nutritional disorders at once, which is why accurate identification matters more here than anywhere else.
- Grown in
- India, Nigeria, Ghana, Kenya, Brazil, Mediterranean
- Season
- Warm season, 90–120 days to first harvest
- Soil & pH
- Well-drained loam, pH 6.0–6.8, high calcium demand
What to scout for on Tomato
- Dark greasy lesions after cool wet nights — late blight
- Lower leaves speckled and yellowing upward — Septoria leaf spot
- Whole plant wilting with green leaves attached — bacterial wilt
- Blossom-end rot from calcium uptake failure, not a pathogen
Diseases that attack Tomato
Late Blight
Phytophthora infestans
Leaf Spot
Septoria, Cercospora, Alternaria spp.
Bacterial Wilt
Ralstonia solanacearum / Erwinia tracheiphila
Mosaic Virus
TMV, CMV, ZYMV
Products you can buy for Tomato
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.
Mancozeb 80% WP
Active ingredient: Mancozeb
- Dose:
- 2.0–2.5 g per litre of water (2.0–2.5 kg/ha in 800–1000 L)
- Interval:
- Every 7 days during cool, wet weather
- PHI:
- 7 days
Protectant only — it must be on the leaf before spores land. Re-apply after 20 mm of rain.
Copper oxychloride 50% WP
Active ingredient: Copper oxychloride
- Dose:
- 3 g per litre (2.5–3 kg/ha)
- Interval:
- Every 7–10 days
- PHI:
- 3–5 days
Approved for most organic programmes. Do not spray in full midday sun on young foliage — copper can scorch.
Ridomil Gold MZ (metalaxyl-M + mancozeb)
Active ingredient: Metalaxyl-M 4% + Mancozeb 64%
- Dose:
- 2.5 g per litre (2.5 kg/ha)
- Interval:
- Every 10–14 days, maximum 3 applications per season
- PHI:
- 14 days
Curative for 2–3 days after infection. Never use alone or more than 3 times — Phytophthora develops metalaxyl resistance quickly.
Cymoxanil + famoxadone
Active ingredient: Cymoxanil 30% + Famoxadone 22.5%
- Dose:
- 0.4 g per litre (400 g/ha)
- Interval:
- Every 10 days
- PHI:
- 7 days
Excellent rotation partner with mancozeb; alternate FRAC groups on every second spray.
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.
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.
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.
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