The Burning Bush Is Dropping Leaves Early

The burning bush is a large, slow-growing species of shrub that produces striking fall colors on its foliage and fruit. It grows well in full sun to nearly full shade. It tolerates air pollution and can adapt to a wide variety of soil types. Premature defoliation is likely attributable to pest infestation, disease or improper cultural conditions. Address symptoms quickly -- early leaf drop may predispose your burning bush to winter injury, pathogens and further insect injury.

Twospotted Spider Mite - The twospotted spider mite is a very destructive and pervasive pest of the burning bush. These tiny pests, which are difficult to see with the naked eye, feed on liquid chlorophyll extracted from the bottom of host plant leaves. Typically, leaves will display yellow spots before prematurely turning red, then brown, and falling off the burning bush. Spray infected plants with a strong stream of water. This will dislodge many mites and may effectively control small population outbreaks. Consider horticultural oils or miticidal soaps to manage more severe population outbreaks. Repeat and alternate product applications. Mites reproduce quickly and can develop a tolerance to frequently used insecticides.

Winged Euonymus Scale - Burning bush, while resistant to the common euonymus scale, is highly susceptible to winged euonymus scale. Scales feed on plant sap from stems and branches of the plant, causing premature leaf drop and branch die-back. Insecticidal soap and horticultural oil, as well as selective insecticides like Talstar or Tempo, can effectively fight this troublesome sucking pest. For best results, apply insecticides while the scale insect is most active during late May or early June.

Euonymus Caterpillar - The euonymus caterpillar is another possible cause of early leaf drop. The caterpillar feeds on burning bush foliage, typically starting at the plant tips and gradually moving inward. It leaves a fine, telltale web in its wake, which can totally engulf the plantin in severe cases. Remove webbing and caterpillars. Consider using a high-pressure sprayer combined with a conventional pesticide, like carbaryl, to eliminate large populations of the species.

Anthracnose - Burning bush is also prone to contracting the fungal disease anthracnose, particularly following extended periods of cool, wet weather. Initially, infected plants will display small brown spots on leaves. However, over time, considerable leaf loss may occur if shrubs are left untreated. Rake up and destroy all fallen leaves. Depending on the severity of the problem, periodic applications of fungicide may be necessary.

Cultural Conditions - Many pest and disease problems that cause premature defoliation are induced or exacerbated by improper care and maintenance. Do not allow roots to soak or dry out. The burning bush has a shallow root system that is easily damaged by extreme conditions in the soil. Also, while the burning bush tolerates a large range of soil pH, avoid highly alkaline soils, which can induce leaf chlorosis and drop.

References

University of Missouri Extension InfoNet: Mites on Burning Bush

Clemson University Cooperative Extension: Euonymus Diseases & Insect Pests

Iowa State University Extension: Extension News: Bugs on Burning Bush

University of Kentucky Department of Entomology: Spider Mites on Landscape Plants

University of Illinois Extension: Ask Extension: Burning Bush

Ohio State University: Euonymus Alatus