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Do your best to prolong the lives of declining shade trees
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Published: August 17, 2008
It is not a comfortable feeling to watch shade trees die or decline without being able to stop it. Sometimes we can and sometimes we cannot. The extended drought and soil moisture deficit has caused a sporadic decline in many large shade trees.
The dryness also causes other problems. Oozing of sap from the trunk that attracts wasps and hornets is common in oaks. Slime flux or "wet wood" often visible on the lower trunk is the secondary infection and trees will leak sap discharging this internal disease. We should take no action by trying to help a tree do what nature allows it to do on its own. We can, however, protect trees from impact injuries that damage the trunk. Lawn mowers and string trimmers are the single most cause of landscape tree decline. This includes all trees, especially the young.
Removing grass and weeds at the base and adding a mulch ring around the trunk is a common recommended practice to avoid injury from equipment.
Watering is something we can do if the soil is very dry and compacted. Water will move more efficiently into the root zone if soil is aerated. The drip or soaker hose method is preferred because the runoff and evaporation is far less than sprinklers.
Bagworms on conifers, especially Leyland cypress, Junipers and even Wax Myrtles are very active. Conifers don't recover well from heavy defoliation.
The worm inside a gray rough textured cocoon is made up of webs and tiny parts of the host plant. The strategy in control is by spraying to leave a foiler residue that is a toxic to the caterpillars as they feed.
Sevin, Malathion, Talstar or Mavrick are recommended insecticides. If there is a heavy infestation in a certain area the surroundings should also be checked close by. There is no need of spraying more than needed until the bagworms appear. If only a few bagworms are present within reach they can be pulled or clipped off. Early feeding stages are difficult to detect as the cocoons are well camouflaged with small green parts of the plants before drying out. Worms never completely leave the bags but instead will detach it and move it around while a portion of their body remains inside.
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