Italian Cypress Aphids

Cause of brown leaves, sticky residue, and dying Italian cypress in LA, Long Beach, and Orange County

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A new, highly destructive aphid pest targeting Italian Cypress trees has rapidly emerged in coastal Southern California. These 2-4mm brownish-gray insects feed in colonies deep within the canopy, injecting toxins that cause rapid, extensive foliage browning, dieback, and even tree death. Because of the prevalence of Italian Cypress trees in the area, they are able to spread at an alarming rate throughout urban and suburban communities.

What Italian cypress aphids do

Aphids feed by piercing tender plant tissue and sucking out sap. On Italian cypress, this feeding can cause foliage to look dull, stressed, or off-color, and heavy infestations lead to needle drop, thinning growth, and ultimately death. Aphids also produce honeydew, a sticky substance that can drip onto branches, nearby plants, walkways, and cars.

Signs to look for

One of the most common signs of aphids is sticky residue on the tree or on objects below it. You may also notice ants, which are often attracted to the honeydew aphids leave behind. In some cases, the tree may look faded, stressed, or patchy, especially if the infestation has been active for a while.

Why they show up

Italian cypress aphids are often more of a problem when the tree is already stressed. Heat, drought, compacted soil, and inconsistent watering can make the tree less able to defend itself. In Southern California, these conditions are common, which is why aphid problems can be more noticeable in long, narrow cypress plantings.

How to manage the problem

The best approach depends on the severity of the infestation and the condition of the tree. Proper watering, reducing stress, and monitoring the tree regularly can help, but the only truly effective solution is proper pesticide usage. A professional can evaluate whether treatment is needed and whether another issue is contributing to the decline.

Schedule a consultation

If your Italian cypress trees are showing signs of aphids, sticky residue, or stress, contact Mink Tree Consulting to schedule a consultation with an ISA Board Certified Master Arborist (BCMA). A professional tree assessment can help identify the problem early and protect the health and appearance of your landscape.