The cheapest place to fix everything
A nursery is a few square metres. Protecting it costs a fraction of protecting the field, and nearly every problem you can prevent there would otherwise be a season-long expense.
Damping off
Seedlings collapse at the soil line, in patches that spread. Caused by Pythium, Rhizoctonia and Fusarium, and driven by overwatering and poor drainage.
- Raised beds, 15 cm or more, always. Flat nursery beds are the main cause.
- Solarise the bed in the hot months — clear polythene over moist soil for three to four weeks kills a large part of the pathogen and weed seed load, and costs only the sheet.
- Seed treatment with a fungicide or Trichoderma.
- ***Trichoderma in the bed medium*, not only on the seed.
- Water in the morning, moderately. Evening watering leaves the surface wet all night.
- Do not sow too thickly. Crowded seedlings stay damp and infect each other.
Netting is the highest-return step in chilli and tomato
Leaf curl virus and mosaic are transmitted by whitefly, thrips and aphids, and much of the infection happens in the nursery, before the seedling ever reaches the field. An infected seedling planted out is a source for the whole block.
A 40-mesh insect-proof net over the nursery, with the seedlings raised inside it, prevents most of this. It costs once, lasts several seasons, and it is the single most effective thing available against virus in these crops. Yellow sticky traps inside the structure catch what gets in.
Rogue before you transplant
Go through the seedlings and discard anything stunted, distorted, mottled or off-colour. It feels wasteful. Planting one virus-infected seedling into a block costs far more.
Hardening
Seedlings raised soft under shade and net, then planted straight into full sun, check badly and take a week to recover. Reduce watering and increase light exposure for the last five to seven days so they go out ready.
Transplant properly
Transplant in the evening, into moist soil, and water immediately. A root dip in a Trichoderma or Pseudomonas slurry at transplanting gives the root zone a head start against soil-borne fungi and costs very little.
Keep the nursery away from the old crop
Do not raise a nursery next to a standing crop of the same family. The vectors simply move across.
A netted nursery and disciplined roguing prevent more virus than any spray programme applied afterwards.
