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Black marks on Tomato Leaves post spraying with Pyrethrum spray for whitefly

Recently sprayed my tomato plants being attacked by Whitefly with a Pyrethrum based spray that was marketed to be specific for tomato plants. Followed instructions however 2 days later my plants have these black scorch marks - I'm assuming it was the spray! Any advice greatly appreciated.


  • Pete.8Pete.8 Billericay, EssexPosts: 7,753
    The best way to prevent whitefly is to grow a few French marigolds and some basil amongst them, it's something I've been doing for decades and never had a problem with whitefly.
    I know pyrethrum is organic but I never spray anything I intend to eat.

    I think you're right - if you sprayed when the sun was out the leaves have probably been scorched. Always best to spray when the sun is not out.
    The damaged leaves won't heal, but it shouldn't cause any long-lasting damage.
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 73,780
    I agree @Pete.8   …. I never ever use any sort of insecticide in my garden … pyrethrum-based products are often considered to be of low risk because they are thought to have low impact on mammals … however it is an insecticide and does not discriminate between ‘pests’ and beneficial insects. It is a danger to all insect life. 

    Remember that pyrethrum is highly toxic to most insects.While it is an effective agent against pests, it can also be deadly to the beneficial insects that pollinate your garden and eat pests.

    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

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