Beware of pathogens and pests

As seedlings are the start of the new crop, you need to take every precaution to ensure the plants remain free of pests and diseases. These will not only compromise the seedlings but cause an outbreak after transplanting.

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DOWNY MILDEW

Daily irrigation, high humidity and relatively low temperatures favour the development of downy mildew, which can grow rapidly on plants of the cabbage family. (The same can occur on other leaf diseases that target tomatoes and peppers.)

Downy mildew attacks the underside of leaves. Because the cotyledonous leaves (the two embryonic leaves that grow from the seed) are very close to the growing medium, it is difficult to spot the problem and treat it. You can use a systemic product (absorbed into the plant), but this should be done only in an emergency, as the fungus can become resistant to the active ingredient. The first systemic product for downy mildew on brassicas was Ridomil, which worked well. But due to overuse, resistance to it grew rapidly.