A Beginner's Guide to Identifying Scale Insects

Scale insects are a type of insect that can be difficult to identify, but with a few key characteristics, you can become a pro at spotting them. They are small, usually between 1-5 millimeters in length, and have a waxy or powdery coating on their bodies.

One of the most distinctive features of scale insects is their shape, which is often rounded or oval. They have a hard, protective shell that covers their bodies, making it difficult to see their legs or antennae.

Scale insects come in a variety of colors, including white, yellow, brown, and black. Some species may have a distinctive pattern or coloration on their bodies.

To identify scale insects, start by looking for small, rounded or oval shapes on your plants. Check for a waxy or powdery coating on the insects' bodies and look for any distinctive patterns or colors.

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Citrus snow scales are relatively small, measuring 1.5 to 2.25 mm in length, and have a distinctive oyster shell-shaped armor with a brownish purple to black color.

The Citrus snow scale primarily attacks the trunk and large limbs of the tree, but can also be found on leaves, twigs, and fruit at high population levels. This scale insect species is present throughout the year, with all stages present at once.

The immature male scale armor is white with parallel sides and three longitudinal sections, one central with two marginal ridges. Adult males are winged and light yellow.

Florida red scales have a circular armor made up of three concentric rings, with a dark reddish brown color and a light brown center. Adult females are about 2.0 to 2.2 mm in diameter.

Florida red scales infest only the leaves, green twigs, and fruit, and are under biological control by the introduced parasite, Aphytis holoxanthus. Some additional insect predators also feed on Florida red scale.

Florida wax scales are highly convex and oval, with a thick layer of soft wax covering the adult female. This wax layer can be white, sometimes with a pinkish cast, and becomes dirty white with age.

Florida wax scales are seldom found in large numbers due to the presence of effective natural enemies. Large amounts of honeydew are secreted by this species.

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Identification Keys can be a bit overwhelming, but don't worry, I've got you covered. There are five keys in total, each designed to help you identify specific types of scale insects.

The Soft Scales key is a great place to start, but if you're looking for something more comprehensive, the Other Scales key is a better bet. This key covers 47 species from 11 families that are considered high-risk or have been intercepted at U.S. ports-of-entry.

To give you a better idea of what's included in the Other Scales key, here's a list of the families it covers:

The Mealybugs Key is a valuable tool for identifying species in three closely related scale insect families: mealybugs (Pseudococcidae), giant mealybugs (Putoidae), and ground mealybugs (Rhizoecidae).

This key was created to help with identification of species that were previously included in the Pseudococcidae or mealybugs family.

You'll need to know the family classification of your specimen to use this key, so if you're not sure, you'll need to go through the scale families key first.

The species included in this key were selected because they were intercepted more than five times at U.S. ports-of-entry between 1995 and 2012, or are considered likely threats for introduction.

Soft keys can be a bit tricky to use, but they're actually quite useful. They're a type of identification key that uses soft, flexible materials like rubber or plastic to create a key that can be easily bent or molded to fit into a lock.

One common type of soft key is the credit card key, which is made from a flexible plastic material. This type of key is often used by locksmiths and can be very effective.

Soft keys can be used to open a wide range of locks, including those with complex mechanisms. They're also relatively inexpensive compared to other types of keys.

A soft key can be made to fit a lock by heating it and bending it to the correct shape. This process requires some skill and patience, but can be very effective.

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The Other Key is a valuable resource for identifying pest scale insects that weren't covered in the Soft Scales or Mealybug keys. It's specifically designed to help you identify insects from 10 different families that are considered high-risk for introduction to the US.

These families include the flat grass scales (Aclerdidae), pit scales (Asterolecaniidae), and false armored scales (Conchaspididae), among others. In fact, there are 47 species from these families included in the key, which can be found in the fact sheet index.

If you're new to using identification keys, here are some tips to keep in mind: Start by familiarizing yourself with the layout and organization of the key.Read each question carefully and choose the answer that best matches the characteristics of the insect you're trying to identify.Work your way through the key step by step, using the process of elimination to narrow down the possibilities.

Some of the insects covered in the Other Key are particularly noteworthy for their impact on plants. For example, the Soft Brown Scale (Coccus hesperidum L.) can secrete large amounts of honeydew, leading to heavy sooty mold on adjacent foliage. This can be particularly problematic for young citrus trees, which can be killed by high populations of the scale.

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Florida red scale is a distinctive insect with dark reddish-brown armor featuring a light brown center. Adult females are 2.0 to 2.2 mm in diameter and produce bright yellow eggs under their armor.

The adult male Florida red scale is small and free-flying, while the female infests leaves, green twigs, and fruit. Florida red scale is under biological control by the introduced parasite, Aphytis holoxanthus.

Chaff scale has an irregularly rounded to oblong shape, measuring 1 to 1.75 mm in length, and is very flat. It's brownish to grayish in color and can be found on bark, leaves, and fruit.

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The Purple Lepidosaphes beckii is a type of scale insect that can be found on various trees in Florida.

This scale insect has a distinctive purple to dark brown armor that is elongated and curved, typically measuring 2 to 3 mm in length. The eggs are found under the scale cover and are pearl white in color, with the crawlers being less than 0.25 mm in length.

Purple scales prefer trees with dense canopies and can be found on leaves, twigs, and fruit. In most cases, chemical control is not required as biological control by parasitic wasps and ladybeetles provides adequate control.

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Mealybugs are a common problem in the Pacific Northwest, and they can be found both indoors and outdoors. They thrive in our mild climate, allowing some species to overwinter successfully.

Some species, like the New Zealand flax mealybug, can even survive the winter months on plants like Phormum.

Pine needle scale can be a real problem for growers, as it disguises itself as part of the plant's anatomy and feeds on profits.

Scale insects, like pine needle scale, can be found on ornamental plants and trees, and can cause significant damage if left unchecked.

Growers can set up an effective Integrated Pest Management (IPM) program to control scale insects, which involves a combination of techniques such as monitoring, pruning, and using insecticides.

Scale insects have a unique life cycle, with females giving birth to live young, and males often not being present or being very rare.

Scale insects can be controlled using a variety of methods, including horticultural oil, insecticidal soap, and neem oil.

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Pine needle scale is particularly problematic because it can be difficult to spot, as it resembles the plant's needles.

Scale insects can be managed through a combination of cultural, biological, and chemical controls, including pruning infested areas, introducing natural predators, and using insecticides.

Scale insects can cause significant damage to ornamental plants, including reduced growth, defoliation, and reduced fruit production.

Growers can use visual inspections to monitor for scale insects, looking for signs such as honeydew, sooty mold, and actual scale insects.

Armored scales are a type of scale insect that can be found on various plants, including citrus trees, euonymus, and camellias.

These scales are typically brownish purple to black in color, with a grey border and a central longitudinal ridge. Their armor is shaped like an oyster shell and has a membranous scale body beneath the outer covering.

Armored scales can cause significant damage to plants, including splitting of trunk bark, yellow spots on leaves, and sparse foliage from leaf drop.

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Florida red scale, a type of armored scale, has circular armor made up of three concentric rings and infests only the leaves, green twigs, and fruit of plants.

Predators such as Aphytis lingnanensis and Encarsia spp. are common biological control agents that attack armored scales.

Citrus snow scales primarily attack the trunk and large limbs of citrus trees, but can also be found on leaves, twigs, and fruit at high population levels.

Armored scales have a unique life cycle, with all stages present throughout the year. Prolonged feeding on the tree trunk can lead to splitting of trunk bark, a symptom more prevalent on young trees.

In managing armored scales, it's essential to scout for them in early spring to monitor for crawler activity. Many natural enemies help reduce scale abundance and damage, so if you notice evidence of predation and parasitism, you may decide to monitor the populations rather than treat with insecticides.

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Scale insects can be a real nuisance in landscapes and nurseries, feeding on leaves or branches of many ornamental plants.

They attach themselves to a plant and feed by sucking fluids through straw-like mouthparts.

Armored scales, soft scales, and felt scales are the primary families that can be pests of ornamental plants, and each group has its own unique characteristics.

Armored scales live beneath a waxy cover that is not attached to the adult body, making it easy to remove the cover and reveal the scale insect hidden below.

Soft scales, on the other hand, secrete a waxy layer over themselves that cannot be separated from their body, and they also excrete sugary honeydew.

Felt scales have waxy filaments and resemble mealybugs, making them difficult to distinguish from other pests.

Armored scales are typically small and inconspicuous, often blending in with plant bark, which can make them hard to detect until populations become very large.

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