Infected Bushes

Question: can someone please identify what has overtaken my bushes in front of my house and how to treat it? thank you

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 11, 2023, 3:25 PM EDT
response: This appears to be Boxwood Psyllid, a common insect pest of boxwoods though generally not one that causes serious long-term damage to the plants. The leaves also show damage (perhaps from prior years) of Boxwood Mite, another typical pest for this shrub. Boxwoods are unfortunately vulnerable to several pests and diseases (though few plants are pest-free, to be fair); the linked page presents these symptoms and discusses management options (when treatments are practical). For psyllid, a strong spray of water from a hose will dislodge most of the insects; since they are still juveniles now, they cannot fly, though some might be able to crawl back onto the foliage. Similarly, periodic sprays with a forceful stream of plain water will also reduce mite numbers, though nothing can heal the damage to leaves already present. In time, evergreen shrubs shed damaged foliage along with a handful of older leaves, a normal process that occurs each year despite being considered evergreen overall. There could also be some old leaf miner damage, and maybe also some winter burn. The management directions on the link provided are pretty straight forward. You can try to prune the infected and damaged leaves out and that should drastically help reduce the population. If you start to see signs of new leaf damage (the mines from the worms) in late June you can treat with a systemic insecticide, just be cautious and read label directions as certain ones can be more harmful for beneficial pollinators. A fungal Volutella infection is common as well as dieback from root decline (such as from overwatering or recurring drought stress) or vole damage around the base of the main stems (especially if heavily mulched).There are disease-resistant boxwood cultivars on the market these days (though they are in the minority), but none are immune to these or other ailments common to boxwoods. Worst-case, if the management of recurring outbreaks of these pests or a disease is too tedious or expensive, consider replacing the shrubs with a different species. Better yet, hedges or other mass plantings or plant groupings are best planted with a variety of species instead of a single species, which makes the planting more resilient in the face of potential problems since not all of the species in the planting will have equal vulnerability to the same issue. Always try to select a species that fits the site space availability well since, even though some shrubs are quite tolerant of pruning, they will be healthier and lower-maintenance overall if allowed to mature to their natural size (or close to it). Fortunately, many shrubs have dwarf cultivars available since small-maturing plants are currently popular. You can prune out and remove any of the branches with brown or dying leaves as well. That will help improve air flow to the plants and push out new growth to cover the damage.  Emily

responder: The Question Asker Replied May 18, 2023, 7:26 AM EDT
response: Thank you. I actually took my leaf blower to the bushes last week and it was strong enough to blow it all off. I haven’t seen it return since so hopefully that did the trick . I appreciate your thorough explanation. Sent from my iPhone On May 11, 2023, at 3:45 PM, Cory Peimer <<personal data hidden>> wrote:﻿Sent from my iPhoneBegin forwarded message:From: Ask Extension <<personal data hidden>>Date: May 11, 2023 at 3:25:25 PM EDTTo: Cory Peimer <<personal data hidden>>Subject: Re: Infected Bushes (#0099416)﻿