Spirea Partial Growth Stunted

Asked June 19, 2014, 5:38 PM EDT

Last year, within a 3 day period, I noticed part of the branches of my spirea were wilting and falling off. When I checked closer, they were covered with aphids, so I used Bayer 3-in-1, which killed the aphids but the part of the plant recovered as far as new growth, but it never grew very tall. When I inquired about it at a nursery last year, they thought the plant would be fine this year. However, the area that was really affected, has only grown as tall as it did last year. When I cut the plant down in early spring, some of the twigs were dead and fell out of the plant. Further investigation, I'm wondering if it could have been scale, not aphids. Would either one of these pests stunt a plant? Will the part of the plant affected ever grow to the height of the rest of the plant? Thank you.

Washtenaw County Michigan trees and shrubs entomology ipm horticulture

3 Responses

Hi
Both insects could have caused stunting but it is also possible that aphids could have transmitted a virus and this cause the decline. In addition if your winter was like ours- colder than normal- it is possible that the new growth failed to harden off going into the winter and the plant suffered winter die-back.

So ... does this mean that the declined part of my plant will never "grow up" even though it has new growth? If the aphids did transmit a virus, why wouldn't the whole plant have been affected? Thank you.

Hi
Chances are the part of the plant that is stunted now will eventually grow out of it. Assuming that it is not a virus. Typically, viruses infect one part and may not show up in anything but the new growth. Nothing about viruses can be put into a box and be described one way, other that the fact that there are no controls and all plant viruses are vectored by something, usually an insect.