7 Tiny Insects That Can Cause Big Problems in Your Landscape This Summer Insects, Mites & Diseases Tree & Shrub Care Summer is one of the busiest seasons in the landscape, and not just for plants. Some of the most damaging pests are active right now, measuring only a millimeter or two in length. Because they're so small, they're often overlooked until the damage becomes impossible to miss. Knowing what to look for early is one of the most effective ways to protect your landscape. Our local SavATree ISA Certified Arborists® routinely monitor and treat for these insects and help homeowners identify problems before they become serious. With a little attention, you can often spot the warning signs, too. Here's what to watch for this summer across the continental United States. 1. Aphids Size: 1-3 millimeters Aphids are among the most common sap-sucking insects in the landscape. They're active from late spring through summer and feed on a wide range of plants, including roses, ornamental trees, vegetables, and flowering shrubs. How to spot them: Look for clusters of soft, pear-shaped insects on new stem growth and the undersides of leaves. Depending on the species, aphids may be green, yellow, black, pink, or brown. Often, the easiest sign to identify isn't the insect itself but the sticky residue it leaves behind, known as honeydew. You may also notice black sooty mold growing on affected leaves or ants traveling up and down stems. Ants feed on honeydew and frequently protect aphid colonies. Why it matters: Aphid populations can grow quickly during warm weather. While small populations rarely cause significant damage, heavy infestations can distort new growth, cause yellowing of foliage, and stress young or already weakened plants. 2. Leaf Miners Size: Larvae approximately 2 millimeters; adults vary by species Leaf miners aren't a single insect species. The term refers to the larvae of several insects — including flies, moths, beetles, and sawflies — that feed between the upper and lower layers of a leaf. They're found throughout the country and commonly affect birch, boxwood, elm, oak, maple, holly, and many vegetable crops. How to spot them: Damage is usually easier to identify than the insect itself. Look for winding, pale trails or blotchy patches within leaves. These feeding tunnels, known as mines, are created as larvae move through leaf tissue. If you hold an affected leaf up to the light, you may be able to see the larva inside. Why it matters: Leaf miner damage is often cosmetic on healthy plants, but repeated infestations can weaken susceptible species such as boxwoods and birches. Because treatment timing is critical, early identification can make a significant difference. 3. Spider Mites Size: Approximately 0.5-1 millimeter Technically, arachnids rather than insects, spider mites earn a place on this list because they're among the most common warm-season landscape insects. The two-spotted spider mite alone feeds on more than 180 plant species, including ornamentals, fruit trees, vegetables, and vines. Hot, dry weather creates ideal conditions for rapid population growth. How to spot them: Place a sheet of white paper beneath a branch and shake it firmly. If spider mites are present, you'll see tiny moving specks on the paper. You can also look for stippled, bronzed, or faded foliage, along with fine webbing between leaves and branches. Why it matters: Spider mite damage can escalate quickly during dry weather, particularly on drought-stressed plants. Left untreated, severe infestations can cause leaf drop, decline, and long-term stress that affects overall plant health. 4. Thrips Size: 1-2 millimeters Thrips are slender, fast-moving insects that feed on flowers, vegetables, shrubs, and ornamental plants. They're particularly common on roses, gladioli, onions, and many annual and perennial flowers. How to spot them: Shake flowers or foliage over a piece of white paper and watch for tiny insects moving rapidly across the surface. You may also notice silvery or bronze streaking on leaves, distorted blooms, or tiny black specks of frass, or insect waste. Because thrips often feed inside flower buds, damage may appear before the insects are easily visible. Why it matters: In addition to feeding damage, some thrips species can spread plant viruses that may have long-term effects on plant health and appearance. 5. Leafhoppers Size: 3-6 millimeters Leafhoppers are wedge-shaped insects found throughout the continental United States. They feed on lawns, ornamentals, roses, grapes, vegetables, and many other landscape plants. How to spot them: Look for small green, yellow, or striped insects that move sideways when disturbed before quickly jumping away. On heavily infested plants, you may find tiny white shed skins on the undersides of leaves. Stippled, bleached, or faded foliage is another common sign. Why it matters: Leafhopper feeding is often cosmetic, but persistent populations can reduce plant vigor and spread diseases that affect the long-term health of valuable landscape plants. 6. Whiteflies Size: 1-2 millimeters Despite their moth-like appearance, whiteflies are closely related to aphids and feed by extracting sap from plant tissue. They're commonly found on tomatoes, squash, hibiscus, gardenias, and many ornamental plants. How to spot them: Disturb the foliage of an infested plant and watch for a cloud of tiny white insects rising from the leaves. Whiteflies typically gather on leaf undersides. Like aphids, they produce honeydew that can lead to sooty mold development. Why it matters: Whitefly populations can build rapidly and become difficult to manage once established. Some species can also transmit plant viruses, making early detection especially important. 7. Scale Insects Size: 1-5 millimeters, depending on species Scale insects are among the easiest pests to overlook because they resemble bumps or growths on the plant itself. They attach to bark, stems, and foliage, where they feed on sap and remain relatively immobile. How to spot them: Look for small, rounded bumps along stems, branches, and leaves that don't easily rub off. Soft scales often produce honeydew, while armored scales may appear dry and shell-like. Yellowing leaves, branch dieback, and declining vigor are common symptoms of infestation. Why it matters: Scale insects can weaken trees and shrubs over time, particularly when infestations go unnoticed for multiple seasons. Early intervention can help prevent long-term stress and decline. Small Insects, Big Consequences Many of the most damaging landscape insects are also the easiest to miss. Regular inspections can help you catch problems before they spread and reduce the risk of costly damage to your trees, shrubs, and other landscape plants. If you notice unusual leaf damage, discoloration, sticky residue, webbing, or declining plant health, don't wait for the problem to worsen. SavATree's ISA Certified Arborists® are trained to identify early signs of insect activity and develop customized treatment plans based on your landscape, the specific pest involved, and local growing conditions. The sooner a problem is identified, the more options you'll have to protect the health, beauty, and long-term value of your landscape. Contact us today to schedule a consultation with an expert arborist.