05/05/2026
Urgent Alert: Scale Insect Epidemic Threatens Reno’s Trees!!!
Reno, our beloved city of trees, is facing a silent but deadly threat: a widespread epidemic of scale insects. These insidious pests are not just a nuisance; they are actively killing our trees, and the problem is escalating. If you have Redbuds, Flowering Quince, Hawthorns, Flowering Pears, Flowering Plums, Cherries, Chokecherries, or other susceptible trees in your yard, now is the time to act. Your trees are at severe risk, and unchecked infestations will lead to their demise.
What Are Scale Insects and Why Are They So Dangerous?
Scale insects are masters of disguise. Unlike typical crawling or flying insects, adult scales often appear as tiny, immobile bumps or waxy coverings on the bark, twigs, and leaves of trees. They are sap-sucking parasites, relentlessly draining vital nutrients from your trees. This constant feeding weakens the tree, making it vulnerable to other stressors and ultimately leading to its death if not addressed promptly and aggressively.
The Silent Killers Among Us: Common Scale Pests in Reno
Several species of scale insects are contributing to this epidemic, each posing a unique threat to our urban canopy. Here are some of the most prevalent and destructive:
Kuno Scale
Kuno scale is a soft scale insect that has been particularly problematic on fruit trees like plums and pears, and can also infest roses and walnuts [1]. These scales manifest as small, rounded, shell-like bumps. The danger intensifies as female scales lay hundreds of eggs, protected beneath their bodies, ensuring the rapid spread of the infestation.
Life Cycle & Impact: The most vulnerable stage is the crawler (spring), when tiny, mobile insects emerge. They settle, begin feeding, and mature into immobile adults by fall, ready to overwinter and repeat their destructive cycle [1]. High populations cause severe water stress symptoms, premature leaf drop, twig dieback, and copious amounts of sticky honeydew. This honeydew attracts ants and fosters the growth of sooty mold, a black fungus that smothers leaves, blocks photosynthesis, and suffocates the tree [1].
European Elm Scale
Our elm trees, a significant part of Reno’s landscape, are under attack from the European Elm Scale. These scales overwinter in bark crevices, emerging in spring to produce vast quantities of honeydew [3].
Life Cycle & Impact: Overwintering as nymphs, they mature in spring, with females producing honeydew that drips onto everything below. Repeated infestations lead to yellowing leaves, early leaf drop, and severe branch dieback. Without intervention, European Elm Scale can kill mature elm trees [3, 6].
Pine Needle Scale
Our conifers, including pines and spruces, are not immune. The Pine Needle Scale (Chionaspis pinifoliae) appears as small, white, elongated specks on needles [4].
Impact: Pinyon needle scale, a close relative, is known to suck sap directly from pine needles. Heavy infestations can quickly overwhelm and kill smaller trees, while severely weakening larger ones, leaving them susceptible to other diseases and environmental stresses [5].
A Direct Threat to Your Redbuds, Flowering Quince, Hawthorns, and Stone Fruits
Beyond these, many other scale species are indiscriminately targeting a wide range of ornamental trees and shrubs. We are seeing significant infestations on:
• Redbud Trees: These beautiful spring bloomers are highly susceptible to various scale insects. Infestations can lead to stunted growth, branch dieback, and a significant reduction in their iconic flowering [2].
• Flowering Quince: Often admired for their early spring blossoms, Flowering Quince are also vulnerable. Scale can cause leaf yellowing, defoliation, and overall decline in plant vigor [7, 8].
• Hawthorns: These resilient trees are unfortunately prone to scale, borers, and spider mites [9]. Scale infestations on Hawthorns can result in weakened branches, premature leaf drop, and a general decline in health, making them easy targets for other pests and diseases [10].
• Flowering Pears, Flowering Plums, Cherries, and Chokecherries: These popular ornamental and fruit-bearing trees are highly susceptible to various soft and armored scales, including Kuno scale and other lecanium scales [1, 12, 13, 14]. Infestations can cause significant damage, including yellowing leaves, premature fruit drop, twig and branch dieback, and a general decline in tree health. The honeydew produced by these scales also attracts ants and promotes sooty mold growth, further compromising the tree’s ability to photosynthesize [1, 13].
The message is clear: if you have these trees, you MUST inspect them regularly.
Urgent Action Required: Management and Control
Controlling scale during an epidemic requires vigilance and a multi-pronged approach. The key is to target the vulnerable crawler stage and ensure thorough application of treatments.
Call 775-323-7755 for more information.
