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Friday - December 03, 2010

From: Georgetown, TX
Region: Southwest
Topic: Compost and Mulch, Diseases and Disorders, Pests, Vines
Title: Fungus Spots on Native Bush Honeysuckle
Answered by: Brigid & Larry Larson

QUESTION:

My native bush honeysuckle plants that I have along my back fence have leaves that are turning yellow with spots. It appears to be a type of fungus, but not powdery mildew. Any suggestions as to what I can do?

ANSWER:

First of all, without seeing your plant, there are lots of possible causes of yellowing and spots, so Mr. Smarty Plants’ diagnosis of the cause is likely to be only slightly more valuable than what you paid for it.    To be sure of what is afflicting your vine you should contact your state's Cooperative Extension Service for an accurate diagnosis.

In searching for the issue of leaf-spots on Honeysuckles, the book “Diseases and pests of ornamental plants” by Pascal Pompey Pirone noted that “Five fungi are known to cause leaf spots of bush-honeysuckle” and goes on to list them.  Several other references also mentioned that the Bush Honeysuckle is subject to fungal diseases such as leaf blight, canker and powdery mildew.  So your suspicion that it appears to be a type of fungus is likely to be accurate.  The only other real possibility for the leaf spots is that it might be the effect of Spider mites.   Gardenguides.com notes that “Aphids and spider mites are common insect pests of the honeysuckle species plants. The honeysuckle aphid causes leaves to curl and turn yellow, while the spider mite makes the leaves appear stippled with red or yellow spots” 

With winter quickly approaching, one very natural thing you can do is clean up the yard.  Trim off all the affected vines and make sure all the leaves and other debris are picked up and discarded in the garbage.  This is one time we won’t recommend that you compost the garden debris!  Honeysuckles are OK with pruning; in fact a possible fungal infection will be decreased by opening up the plant, which can be quite dense, to light and good air circulation.

Yardener.com has some good advice for control with natural fungicides. They suggest using baking soda, Neem extracts and/or control with sulphur.  They also have a very appropriate section on Control without fungicides that looks a lot like my “cleanup” advice above.

That’s a reasonable set of suggestions for fungi, but what about spider mites?  Once again, cleaning up is one of the better first steps.  If they are still there in the Spring – then maybe insecticidal soap spray is an effective natural control for insects including both the spider mite and the honeysuckle aphid.

Diervilla sessilifolia (Southern bush honeysuckle)    Diervilla lonicera (Northern bush honeysuckle)

                                     

 

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