Question
Brown Top
I've had 2 dwarf alberta spruce (spiral cut) since 2006 planted in front of the house. I live in Carroll County MD. Outside of spider mites, all has been well. About two months ago, I noticed that one of the spruces' top was totally brown & looked dead. I've searched online & seen anywhere from trunk/root problems to spider mite issues. The only thing that is planted closely to the spruce are hydrageas & a few bulbs.
Can I cut the top off to save the rest of the spruce? Or is the whole spruce dying? Should I replace it w/the same? If I do replace it w/the same, what can I do to prevent the new spruce from dying?
AnswerSounds like spider mites.
Spruce Spider Mite: Mites are not insects but are more closely related to spiders. Spruce spider mites (Oligonychus ununguis) are occasional pests of spruce. They are very small and not seen easily with the naked eye. They have piercing mouthparts that they use to suck plant sap. Their feeding results in speckling (formation of tiny yellow spots) on needles. Some needles may turn brown and drop off. With heavy infestations, fine webbing may be seen on the plant. Several seasons of heavy mite feeding may kill a spruce. Although most spider mites increase in numbers during hot, dry weather, spruce spider mites are cool-weather mites. Their populations peak during spring and fall, but drop dramatically during the heat of summer when predators feed on them.
To determine whether insecticide use is needed, it helps to know how many mites are present. Hold a white sheet of paper under a branch and strike the branch. The mites that are knocked off will be seen crawling around on the paper. If dozens of mites are seen per whack, serious damage can result. Continue to check population numbers at 7- to 10- day intervals. Pesticides labeled for homeowner use against spruce spider mite include insecticidal soaps and acephate + fenbutin oxide (Ortho Systemic Insect Killer or Ortho Orthenex Garden Insect & Disease Control Concentrate). Completely cover the foliage with the spray. As with any pesticide, read and follow all label directions and precautions before using.
