Issue: Octob1r 6, 2001

Pinon tree making fine spray below branches


Our pinon tree is dripping sap in large amounts. The tree grows over our flagstone patio, and the patio is covered with a fine spray of sap or pitch. Is there anything we can or should do to prevent this? -via internet (Santa Fe)


I suspect that the problem is pine aphids because you described the problem as a fine spray. The aphids that would be on your pinon look like clusters of small spiders on the branches (they have longer legs than most aphids and look like spiders). They feed on the sap from the tree and excrete a sugary substance called "honey dew." The honey dew is the fine spray that you are seeing on the patio. The answer to this problem is to reduce the number of aphids on the branches. You can use insecticides, but in many cases washing the branches of the pinon with a strong jet of water will knock the aphids out of the tree. The aphids will try to climb back into the tree, but many will not succeed. If you wash the branches frequently (once a week or so), you can reduce the population of aphids enough to control the problem. By the way, the reduced number of aphids will do little damage to the tree, so washing should be sufficient to solve the problem.

Composting leaves in the fall


What will happen to leaves I put into my compost this fall? Will they wait until spring when it gets warmer to decompose?


If you add green grass clippings, manure, or some other source of nitrogen to the leaves, they will decompose through the winter. The heat in the compost is generated by the composting organisms; it does not come from the air. Of course, the air may cool the compost and slow the decomposition process around the edges of the compost, but the center should generate enough heat to continue composting through the winter.

This depends on the balance of materials in the compost. A source of nitrogen, such as green grass clippings or manure, should be mixed with a source of carbon such as brown leaves or shredding branch trimmings. The nitrogen and carbon are the foods needed by the composting organisms such as fungi and bacteria. They will generate heat and decompose the landscape debris so that in the spring you will have a supply of compost to add to your garden as a soil conditioner.

Just remember that you will need to supply moisture to the compost and to turn the compost materials through the winter.

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Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

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