Images: bugwood.org. 1. Joseph O’Brien, USDA Forest Service 2. Paul Weston, Cornell University 3. PA DCNR-Forestry Archive 4. Brian Sullivan, USDA APHIS PPQWith live plants and wood being transported around the country (and the world), the chances of spreading non-native insect and disease problems are essentially unbeatable. That’s why it’s so important to remain vigilant about the health of your trees and shrubs. Our Arborists and Plant Health Care technicians always stay apprised of the latest threats to the plant material in our area so that we can take the proper course of action and not waste time with misdiagnosis. These are a few of the more serious insect and disease threats to our native trees and shrubs.
1. Traveling up from Texas, Oak Wilt has recently been detected in Upstate New York–the closest it’s gotten to us so far. Primarily affecting trees in the Red Oak family, the disease is caused by the fungus Ceratocystis fagacearum, which clogs the vascular system of a tree. The leaves on trees with the disease begin to wilt in late May to early June, with the edges appearing scorched. Trees killed by Oak Wilt often house pads of fungal spores beneath the bark and emit a strong fruity wine smell.
2. Originally from Europe, adult and larval Viburnum Leaf Beetles feed on the leaves of the popular ornamental trees and shrubs in the Viburnum family, leading to very heavy defoliation. With this beetle, prevention has proven to be the best medicine: the most effective control is to interrupt the life cycle by removing twigs containing the beetles’ eggs in the fall or winter before they hatch in the spring.
3. The Asian Long Horned Beetle (ALHB) made it’s way to the US via wood palettes being shipped from Asia, with its first outbreak in the New York metro area. In their larval phase, ALHB’s cause irreparable damage to a variety of hardwoods by boring deep into the trunk and branches. In addition to decline, one of the easiest to spot symptoms of an ALHB infestation are the large exit holes created by the beetles.
4. Named for its brilliant color, the tiny Asian Emerald Ash Borer was first noticed in Michigan and Ontario and is quickly encroaching on the Northeastern US. The beetle larvae bore into the trunks of Ashes and feed on the inner bark, leaving D-shaped exit holes and cracks in areas with high activity. The destruction of tissue in the tree disrupts nutrient flow and causes parts of the canopy above the infestation to die.
