Fungal disease – tips to help avoid it

After the wettest June on record in the UK, helping to prevent fungal disease seems to be among the most useful subjects to discuss at the moment.

These diseases may be divided into two groups:

  • Those that start at root level
  • Those that start at leaves

Below Soil
Even if you grow your plants outside in the rain, you may still be able to stop the soil from becoming saturated (cover with plastic sheeting) and therefore, help prevent Fusarium and Verticillium Wilt – two fungal diseases that begin at root level. They clog-up a plant’s plumbing system and the first sign is wilting.

Above Soil
For those who grow their tomatoes in a greenhouse or polytunnel, the main problem is damp air and therefore damp leaves. There are many fungal diseases waiting to attack your plants above ground including, grey mould, leaf spot and blight.

To help avoid these diseases …

  • Cut down on watering
  • Increase air circulation
  • De-leaf plants up to the first truss
  • Try not to place plants too closely together
  • Remove dead leaves and any decaying matter from the area of your plants
  • Spray with chemicals as a prevention – Systhane (replacement for Dithane) or Bordeaux Mixture

systhaneKeep Plants in Top Condition
Tomato plants have immune systems and become more vulnerable to disease when light levels and temperatures are low and the air is damp.

A healthy plant has a stronger immune system than one that is slightly under the weather (sorry about that!) so keeping plants in top condition is also a good way to prevent disease.

There are now bio-fungicides available that work by protecting plants with “friendly fungi” which stop the “unfriendly fungi” from getting established. Sounds good … when the weather is this bad, we need all the friends we can get!

5 Responses

  1. Mike Darlington
    | Reply

    I have just received some recently on-line purchased 5 Tomato Plants of each, of the Ferline and Nepal variety, in the same box. I was shocked and surprised that 2 of the Nepal plants had definite evidence of Blight fungal disease on some of their leaves while the Ferline appeared unaffected. I realize that the Nepal, as an older variety, will have little resistance, while the other newer variety is more resistant. If I remove the infected leaves from the Nepal, spray all the plants with a product such as “Bayer Fruit and Veg Disease control” and isolate them, should this be successful? Otherwise, am I wasting my time and should I just destroy them all? Regards Mike

    • Nick
      | Reply

      Hi Mike,
      I would do as you suggest – remove the effected leaves and spray. If the blight has reached the stem, it is probably too late even with the spray.

  2. Rhys Jaggar
    | Reply


    Any links to the bio-fungicides which use ‘friendly fungi’?

    Have I missed it on one of your previous newsletters?

    • Nick
      | Reply

      Hi Rhys,
      I believe that Serenade Biofungicide will be available in the UK soon.
      Check out this link:

      • Mark Downing
        | Reply

        Thanks for posting the link, Nick. Sounds promising!

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