How to Prevent Scale on Redbud Trees

Healthy, budding redbud

Eastern redbud (Cercis canadensis) is a medium-size ornamental tree, beloved for the gorgeous pink blossoms that burst from its branches in spring. Unfortunately, redbud is prone to a number of pests and diseases, with scale insects being one of the nastiest. They won't kill a redbud, but scale can weaken it by sucking sap from the twigs, branches and trunk. Scale can be controlled with pruning and spraying, but it's better to prevent infestations.

Things You'll Need

• Pruning shears
• Mulch
• Pest-resistant plants

Instructions

1. Hunt for scale insects on your property. Scales aren't carried on the wind; they come from other plants. Look for the sticky residue, called honeydew, that scale insects secrete as they feed. If you find an infested plant, prune away the damaged twigs and leaves, and destroy them. Cut back other trees so that branches don't overhang or mingle with the redbud's.

2. Avoid the use of broad-spectrum insecticides. Scale insects have a number of natural parasites and predators that control their numbers. Among these natural enemies are ants, wasps, lacewings and lady beetles. Spraying all-purpose insecticides near the redbud kills these beneficial bugs, and the scale population, if there is one, will expand rapidly.

3. Grow pest-resistant plants, especially near the redbud. Plant species that are native to your region, choosing only the healthiest specimens from the stock of a reputable nursery. Address any insect or fungus problems promptly when they occur, because the healthier the rest of your landscape, the better off your redbud will be.

4. Keep your redbud healthy and the soil weed-free. Redbuds need full sun, moist, well-drained soil, and plenty of space for good air circulation and light penetration in their canopies. Use mulch to keep weeds down, as some scale insects can crawl up a weed and onto the redbud. Spread the mulch 2 to 4 inches deep in a 3-foot ring, starting 6 inches from the trunk for best results.

Tips & Warnings

• Rake out and replace mulch annually for maximum benefit, and never let it pile up against the trunk of the redbud, where it will cause rot and girdling, and will kill the tree.

References

• University of California; Scales; 2007
• University of Georgia; Redbud Tree; Michele Brown
• University of Illinois; Eastern Redbud; Rita Kemme; 2009

Resources

• Virginia Tech; Scale Insects; Eric Day; May 2009