While it can be frustrating to see your pecan tree dripping, many people mistakenly think the tree is sapping and want to know how to stop it. In reality, your tree probably has yellow aphids, which tend to affect pecan trees anywhere from June to July, leaving a substance behind known as honey dew. For best results against yellow aphids, use an insecticide with 1.47 percent imidacloprid, such as Bayer Advanced Tree and Shrub Insect Control.
Measure around the trunk of your pecan tree at chest height, in inches. Use this number of ounces of insecticide to treat your pecan tree. For trees with multiple trunks, measure each trunk, add the measurements together and multiply by 0.75 to determine the number of ounces for treatment.
Add the appropriate amount of insecticide to 1 gallon of water in a bucket and mix well. If your total is 50 oz. or more, use 2 gallons of water so the solution doesn't become too concentrated.
Pour your mixture around the base of your tree, as close to the trunk as possible. This will allow the roots to absorb the insecticide and send it through the body of the tree.
Refill the bucket with 1 gallon of clean water. Pour the water around the trunk of the pecan tree to further dilute the solution.
Repeat the dosage only once a year, preferably in the fall, to protect your tree for a full 12 months. Annual usage will help prevent aphids from affecting the tree at all.