Knowledgebase

Leaf Mottling #763274

Asked July 22, 2021, 3:20 PM EDT

I have various plants in my backyard that have a problem with their leaves: bleaching out with yellowish veins. Have a picture from a dahliia plant. Leaves the same on catnip, snap dragons, impatiens, rosemary. I recently sprayed copper fungicide for powdery mildrw but this had started before that. I've used a liquid organic fertilizer amd some miracle gro but not all plants receivef one or both. I have attached leadlf pictures from the dahlia.

Montgomery County Maryland

Expert Response

These tiny white/yellow dots (referred to as "stippling") can be produced by several types of insects with sucking mouthparts: leafhoppers, thrips, and/or spider mites are some of the possible culprits. Spider mites tend to be a problem in very hot, dry conditions, and dahlias, in particular, are susceptible. Take a look at our page on spider mites and how to monitor for them: https://extension.umd.edu/resource/spider-mites-flowers-and-groundcovers

In general, this type of insect damage will not affect flowering. Use a strong spray with a garden hose periodically on the symptomatic plants, which will help to disrupt feeding by dislodging these insects. 

Christa

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied July 23, 2021, 10:24 AM EDT

Loading ...