Arizona Cyprus Trees Problems

Arizona cypress (Cupressus arizonica) is a fast-growing tree that grows to a mature height of 50 feet with a 30 feet spread. The tree is a popular choice for creating natural fences. This evergreen tree has a conical crown, a smooth reddish bark and blue-green foliage. Arizona cypress thrives on the dry, rocky mountain slopes and canyon walls in its native habitat. The low-maintenance tree adapts well to better quality soil and more ample watering. However, Arizona cypress is susceptible to a number of diseases and pest infestations.

Cypress bark beetles (Phloeosinus cristatus) are native Arizona insects that can seriously damage or kill Arizona cypress trees. The insects are more likely to infest and damage trees that are drought stressed. Cypress bark beetles are about 2 to 3 mm long and reddish brown to black. The insects mate and reproduce in the weakened trunks and limbs of less vigorous trees, girdling the limbs and reducing the flow of nutrients through the tree. The best control option is employing cultural practices that lead to healthy and vigorous tree growth. There are no pesticides recommended for the control of the insects.

Cypress bark mealybug (Ehrhornia cupressi) is a pink mealy bug also referred to as a scale. The insects are covered with a loose white wax and can attack Arizona cypress trees among other tree species. The insects lead to the yellowing, browning and red color of the foliage of infested trees. As insects spread through the tree, the health and vigor of the tree declines and there is the appearance of waxy, white threads on the bark. Chemical control options of cypress bark mealybug in more heavily infested trees includes the use of horticultural oil.

Canker is a potentially lethal fungal disease of Arizona cypress caused by the fungus Seiridium cardinal. The canker is common on cypresses growing in hot, dry climates. The cankers appear on the twigs and branches and start to girdle the trees. Control of canker is difficult since fungal spores spread rapidly with rain, infected tools, insects and birds. Often the only remedy is to remove and destroy the entire tree in case of heavy infection. Mildly affected trees need heavy pruning and periodical spraying with a copper fungicide at the start of rainy season.