Garden Detective: area sycamore trees hit with fungus
Sycamore trees can be susceptible to fungal disease anthracnose. Credit: Fotolia
DEAR JESSICA: Help. All the sycamore trees in my neighborhood are losing their leaves at an incredible rate. The leaves seem to have a fungus on them. Any idea what's going on?
-- Francis De Angelis, Massapequa
DEAR FRANCIS: You're not the only reader who has noticed sycamore trees dropping leaves, so something is definitely going on. I can't be sure without seeing the trees and foliage, but the fungal disease anthracnose is likely the culprit. I reached out to Julie Seghrouchni, horticulture and community forestry educator at the Cornell Cooperative Extension of Nassau County, and she told me several sycamore leaves that have been brought to the lab have been diagnosed with the disease. Although anthracnose can affect many hardwood trees, Seghrouchni said symptoms are especially severe on sycamores, which can become almost completely defoliated in April and then refoliate later in the season.
"Management practices that allow better air movement and more sunshine, such as thinning, may inhibit the diseases by helping the foliage dry rapidly after a rain," Seghrouchni advises. "Anthracnose can be reduced by raking leaves and pruning infected twigs and branches to reduce the amount of pathogen, then disposing of the affected material by bagging it, not composting."
In coastal areas, the disease is often more severe because of the misty conditions, she said, which explains why all the letters I've received about sycamores have come from readers on the South Shore.
DEAR JESSICA: We found this freaky-looking beetle on our fence. Its main body is about 3 or 31/2 inches long, and it has a yellow tail. We have never seen anything like this, nor have any of our neighbors who came over to check it out.
--Geoff Martin, Farmingdale
DEAR GEOFF: What you've got there is a female Prionus laticollis, commonly called a broad-necked root borer. The ominous-looking yellow "tail" is not a stinger, as you might fear; it's actually an ovipositor, which she uses to deposit her eggs into the ground. The larvae then tunnel deeper into the soil and feed on tree and shrub roots until they mature. Attacks can be harmful -- even fatal -- to some woody plants, but there are no known effective control methods.
DEAR JESSICA: My holly tree, which started out as a 2-inch seedling and is now 45 years old, is usually full of red berries. However, this year they did not last for more than two weeks. They have all shed, making a mess on my steps. Why did this happen?
--Mary C. Nicotra, Flushing
A female broad-necked root bore (prionus laticollis). Credit: Handout
DEAR MARY: Hollies sometimes react to unusual weather patterns, like the unseasonably warm weather we experienced, or drought, by dropping berries. Berry loss also can occur if the soil pH is too high, as hollies thrive best in acidic soil with a pH of 4.5-5.5. If you've recently applied lime to a nearby lawn, you might have inadvertently raised the soil pH around the holly. If this is the case, you might also have noticed some yellowing of the leaves.
In addition, hollies are dioecious, which means a nearby male is necessary in order for the female to produce berries. If a female begins berry production but is not properly pollinated by a male, those berries will drop. If you had two trees in the past and recently removed one, that would explain the problem. However, the male needn't be in the same garden bed: A tree in your neighbor's yard could actually have been pollinating your holly, so if you have had only one tree all along, it's possible that someone living nearby removed your pollinator.
Reader note: The Cornell Cooperative Extension of Nassau County office, formerly in Eisenhower Park, has moved to 832 Merrick Ave. in East Meadow. Walk-in and horticulture hotline (516-565-5265) hours are Tuesdays from 10 a.m. to 4 p.m., and Wednesdays and Thursdays from 10 a.m. to 1 p.m.
