|I have a hedgerow along my driveway made up of seven burning bushes. They are about 4 to 5 ft. tall and wide at this point. I did not plant them so I'm unsure of their age. The leaves on the middle bush are turning reddish brown (not red like you expect to see in the fall) and dropping off. At first it appeared to be just a couple of branches. I pruned out the dead growth assuming it was an isolated problem, but now the entire bush is beginning to do the same thing. The problem is not affecting the surrounding bushes, at least not currently. I was hoping you could diagnose the problem and recommend a solution.|
|Diagnosing a plant problem without having an opportunity to inspect the plant is a really difficult proposition! However, what you describe sounds like mite damage. Twospotted spider mites are tiny and difficult to see with the naked eye. Adults (eight legs) and nymphs (six legs) are light green to greenish yellow with two lateral dark spots. The life cycle from egg to adult can occur in five days at 75 degrees F, thus several generations occur from late spring through fall. Adults overwinter in protected places away from host plants. Violets and weeds are common winter ?hosts.?
Control measures for twospotted spider mite:
Water host plants during dry periods. If needed, apply fertilizer at the minimal rate during early spring.
Monitor for spider mites by shaking host foliage over white paper. Plant-feeding mites produce a green streak when smashed compared to the red streak for beneficial mites.
If two spotted spider mites are present, spray foliage with a biorational product (e.g. horticultural oil, insecticidal soap, abamectin, bifenazate or spinosad) or a specific miticide (e.g. bifenthrin, hexythiazox, malathion, or permethrin) when mites first appear. Repeat as often as monitoring shows mites and at an interval permitted by the product label.
Another common pest of burning bush is the winged euonymus scale. This tiny insect also feeds on basswood, elm and willow. Scales remove plant sap from stems and branches with a thread-like mouthpart. Feeding can cause premature leaf drop, branch dieback, and predispose the plant to winter injury.
Winged euonymus scales have a small (2mm long), brown to gray, oystershell shape waxy cover protecting a white scale body. This scale is found on twigs between ?wings? of burning bush. It has 1 generation/year, overwintering either as eggs or partially mature scales. Eggs hatch in late June through July.
Control measures for winged euonymus scale:
Water host plants during dry periods.
Examine infested twigs when egg hatch is expected, looking for whitish, flat crawlers.
If crawlers are observed, spray twigs/branches with a biorational product (e.g. horticultural oil or insecticidal soap) or a specific insecticide (e.g. carbaryl, cyfluthrin or malathion) when crawlers first appear. Repeat application if needed due to long crawler hatch period.
Hope this information is helpful!