Questions On: Tree Insects
Ron Smith, Horticulturist, NDSU Extension Service
Q: Our neighborhood has pine trees (Ponderosa pine, I think) in front of each home. They were planted by the city. Our tree produces more sap than any other tree in the neighborhood (I estimate 10 to 20 times more). It has ruined the paint on our car and it is tracked into the house and it soils our flooring. Is there anything I can do to reduce the amount of sap produced by our tree? It may get more water than most of the other trees, but there are no other differences that I am aware of. Any help that you can provide will be appreciated very much. (E-mail reference, Cerritos, Cal.)
A: You folks have a nice long growing season, which can spell trouble insect-wise. Your tree could be infested with scale or aphids which secrete a "honeydew" from their feeding habits that create the mess you are describing. If that is the case, these insects are easily ID'd and controlled with a low toxicity spray. If the insects are not present in sufficient number to be the cause of the sap flow problem, then I'd suggest spraying the tree every 12-16 weeks with an anti-desiccant like Wilt-Pruf or something similar. This product, it goes on milky and dries clear, sealing the stomates and hydathodes, which are openings on the foliage, reducing the flow of sap somewhat. As new growth emerges, it of course, must be covered with this material. Since this interferes with the normal gas exchange in plants, it will slow down growth, but that shouldn't be a concern from your description of the situation.
Q: I am having problems with my Ponderosa pine. They have dark or even black coloring on the new buds and ants all over the trees. The trees are 3 years old and the problem is in only one row. Colorado blue spruce and Scotch pine in the same planting have no problems. I looked through some literature that I have and found nothing. Do you have any ideas as to what the problem is and a solution? (Amidon, N.D., e-mail)
A: I suspect it could be either a saprophyte that has developed -- aphids feeding and exuding their "honeydew" which is attractive to ants--or a bacterium. My hunch would go with some aphids in the buds. Spray with Orthene to see if that helps control the problem. Often, aphids' honeydew exudate causes a black saprophytic fungus to grow over the foliage, and when the ants find it, they go nuts!
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