Forum home› Problem solving
This Forum will close on Wednesday 27 March, 2024. Please refer to the announcement on the Discussions page for further detail.

Dahlia have yellow dust and fine silk webs, then turned brown and dying

hyatanhyatan Posts: 9
in Problem solving
Help!, my dahlia was growing well and suddenly have fine yellow dusts and fine silk webs.  Now it has turned crispy brown and the whole plant is dying.  The neighbouring geraniums seem fine.  I though it was fungus and sprayed it with multi purpose systemic fungicide but it seems in vain.

Posts

  • fidgetbonesfidgetbones Posts: 17,618
    I think it has spider mites, very tiny insects, usually on the underside of leaves.
  • BobTheGardenerBobTheGardener Posts: 11,384
    Agree and they are resistant to all of the 'bug sprays' which are available to gardeners.  I don't think there is any way to control an infestation that severe.  I would either throw the whole plant into the black bin or cut off all growth and hope it sends up new shoots.  If you take that route, spray/mist it with water several times a day if the weather remains hot as spidermites hate wet, humid conditions.
    A trowel in the hand is worth a thousand lost under a bush.
  • Pete.8Pete.8 Posts: 11,340
    I had the same with one of my dahlias in a pot. Almost overnight the top 1/2 looked like yours. I cut the plant right back to where there were some unaffected leaves and its growing well again already.
    Being of the spider family, there are no sprays available to gardeners that are effective. Neem oil has been suggested, but I doubt that would work for your plant.
    All I can suggest is as Bob has already said. Cut it back really hard, keep it well watered and cross your fingers.
    Spider mites love it dry and hot, so that's why we've got them this year. In a humid atmosphere they wont thrive.

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • hyatanhyatan Posts: 9
    Thank you Figetbones, BobtheGardener and Pete8 for all your advices.  I really love my velvet red Dahlia so will repot it somewhere else, cut it right back and hope that I have saved the plant.
Sign In or Register to comment.