Sap raining down from oak tree Town of Miller Place

Asked August 3, 2017, 7:38 AM EDT

Sap has been literally pouring from a 100ft oak tree in my yard. Our tree company sprayed it and its still coming down. We can't use our yard, before I have it taken down I want to make sure there is nothing else we can do to save it. Also tiny acorns are falling like crazy.

Suffolk County New York

2 Responses

You don't indicate in your note what the tree company sprayed the tree for. Did they determine that it's been infested with a specific pest such as aphids? If your problem is aphids the liquid is "honeydew," the insects' excrement, and not sap from the tree. Aphids are the most likely pest, and I am pasting some information about aphids from the US Forest Service below. Since the tree is 100 feet tall it is probably also something on the order of 150 years or more old, and it would be worth getting a second (or even third) opinion from a certified arborist in your area so you don'f cut down such an ancient tree for something that can be treated. Here is a link to the Society for Arboriculture page where you can find an arborist close to you.

Info about aphids:

Following is an explanation of the 0ak leaf aphid from the U.S. Forest Service.

Importance – Oak Leaf Aphids infest the undersides of leaves, leaf stalks and tender twigs of trees in the red and white oak groups throughout the East. Heavy infestations distort the foliage and weaken the plants. Distorted foliage will take on a curled appearance. Honeydew and sooty molds further mar the beauty of ornamentals.

Identifying the insect – The aphids are .04 to .06 inch (1 to 1.5 mm) long, soft-bodied, pearshaped, with a pair of cornicles (look like horns) at the bottom of the abdomen. They may be yellow, green, pink, or brown, with darker-pigmented blotches on the abdomen and dusky bands on wings. Winged and wingless forms occur.

Identifying the injury — Clusters of aphids feed largely on the underside of the leaves. Feeding injury curls and folds the leaves. Every leaf on a tree may be curled and distorted during heavy attacks. Leaf surfaces become sticky with honeydew followed by growth of black, sooty fungus.

Biology — Overwintering occurs as eggs deposited in bark crevices of host plants. The eggs hatch in the spring, and nymphs begin feeding on the leaves. There are several generations per year, but the highest populations have been observed during the spring.

Control — Natural enemies usually keep infestations in check. Insecticides are sometimes needed on ornamentals and other high-value trees. Insecticidal soap, neem oil and narrow-range oil (e.g., supreme or superior parafinic-type oil) provide temporary control if applied to thoroughly cover infested foliage. To get thorough coverage, spray these materials with a high volume of water and target the underside of leaves as well as the top. Soaps, neem oil and narrow range oil only kill aphids present on the day they are sprayed, so applications may need to be repeated. And, as always, make sure you read and follow the label directions.

Not Aphids, which is what they sprayed for!