A light aphid infestation may not be serious but heavy infestations cause distorted and stunted growth and produce large amounts of honeydew. The honeydew serves as a substrate for sooty mold. Aphids may be controlled with sprays of Orthene or malathion.
Birch skeletonizer feeding causes leaf browning. The skeletonizer larva is yellowish-green and one quarter inch long. No chemicals are currently registered for this pest on birch.
Birch leaf miner is a common insect pest of birch. A small white worm eats out the middle of the leaf which turns brown. Severe attacks of birch leaf miner predispose trees to bronze birch borer infestation. The insect shows up in mid May but timing can vary with the season. The first of two generations per year is the most damaging. Birch leaf miner can be controlled with sprays of Orthene or Diazinon applied when the mines first show up.
The most serious pest of landscape birches is bronze birch borer. Stressed tree are most susceptible to borer attacks. The insect bores in the sapwood, beginning in the top third of the tree, causing death of the tree crown. The tunnels are slightly raised and faintly rust colored. Emergence holes in the trunk are shaped like capital D's. Keep the trees healthy by controlling other insects, fertilizing, and watering as needed. Chemical control is applied to the trunk and main branches. The first spray is usually applied June first with 2 additional sprays at 3 week intervals. Timing of the first spray will vary from year to year depending on weather conditions. A commercial sprayer may be needed to apply the spray adequately. Use Dursban.
|Visual title - Visual size||Visual title - Visual size|
|Bronze Birch Borer - 40K||Birch midge galls - 29K|
|Birch midge damage - 28K||Birch leafminer - 57K|
|Birch leaf miner second generation damage - 24K||Birch leaf miner adult - 31K|