GOOD BUG – BAD BUG

Lady Beetles

These are among Florida’s most beneficial insects. Both adults and larvae prey on aphids, scale insects, mealybugs, mites and other soft-bodied insect pests. Adults are oval and most are orange or reddish with black markings, or black with yellow or red markings. Most species are about 1/4” long but range from 1/16 to 1/2 “. The larvae are elongate, somewhat flattened and covered with small spines. They are usually dark or black with brightly colored spots or bands. Some larvae are white and resemble mealybugs. Both adults and larvae are frequently found feeding among aphid populations.

Sevenspotted Lady Beetle	Sevenspotted Lady Beetle larva

Lacewings

These are common insects, found on grass, weeds, cultivated row crops and shrubs. Most are greenish with copper-colored eyes and are about 3/4 ” in length. The adults may be predaceous or may feed on pollen. The white eggs are attached to foliage by thin stalks that are about 1/4 ” tall to prevent the larvae from preying on each other. The larvae are elongate and have large, sickle-shaped mandibles. They are predaceous and feed primarily on aphids, thus the common name “aphidlion.”

Green Lacewing	Lacewing larva	Lacewing eggs

Syrphid flies

These are commonly found on flowers and are also known as flower flies. The flies vary greatly in color and size; most are yellow with brown or black stripes on the abdomen. Many syrphid flies resemble wasps, and others closely resemble bees, but do not sting. Adult flies feed primarily on pollen. Many syrphid larvae are predaceous, especially on aphids. The larvae are slug- or maggot-like, have no legs or visible head and are usually a greenish, translucent color.

Syrphid fly	Syrphid fly larva

Parasitic wasps

These wasps are very small – most are less than 1/8” long and usually are not noticed. They lay their eggs on or in the body of a host insect and the immature stage consumes the host’s tissues over a period of time, eventually killing it. Pupation may occur in or on the host. Some wasp larvae construct many small white cocoons on the body of their host. Other species pupate inside their host, and the emerging wasp leaves a small circular hole in the host’s body as evidence of parasitism. These wasps parasitize many harmful insects such as scales, whiteflies, aphids, leafminers and caterpillars.

Parasitic wasps	Parasitized aphid	Braconid wasp pupa

Stink bugs

Many stink bugs are harmful, but some species are predaceous. Stink bugs are usually oval or shield-shaped and brown, green or gray, but many are brightly colored. A common predaceous species in Florida is midnight-blue and orange. As a general rule, beneficial species can be identified by spines projecting from their thoraxes; plant feeders have round “shoulders.” Predaceous forms have short stout beaks while

plant-feeding forms have long thin mouthparts. They prey on many insects, especially caterpillars.

Green stink bug	Predaceous stink bug adult

Assassin bugs

These insects are generally black or brown, but many of them are brightly colored. They are 1/2” to 1” in length. The head is elongate with a short, curved beak. These bugs are usually found on foliage, where they attack many harmful insects. Caterpillars are their favorite prey. Many species will inflict a painful bite if handled.

Three legged Assassin bug	Assassin bug nymph

Ground beetles

Both the adults and larvae of ground beetles are predaceous upon harmful insects. As the name suggest, they are usually found on the ground, and are most active at night. Adult beetles are 1/4“ to 1” long and are generally black, but often are metallic-colored. They prey on some of our most serious lawn, vegetable and field crop pests including webworms, armyworms, cutworms, corn earworms, small mole crickets and others.

Mole Cricket –egg to adult	Ground Beetle

Earwigs

Many earwigs, especially the striped earwig, prey upon insects such as chinch bugs, small mole crickets, sod webworms and other insects that live on the soil surface. This large species is 3/4 “ to 1” long and brown, with longitudinal dark stripes on the thorax and wings. In laboratory experiments this earwig commonly consumed 50 chinch bugs a day.

Chinch Bug Nymphs	Earwig

Predaceous mites

Some mites prey upon spider mites, small insects and eggs. These large, active mites are about 1/25” long and are orange to brown. Predaceous mites are reared and released in greenhouses to reduce plant-feeding mite populations.

Predaceous mite

Spider mites

These are among the most common pests that attack ornamental plants in Florida. The two-spotted spider mite is the most common. They are not insects but are more closely related to spiders and ticks. Adult spider mites, spiders and ticks have eight legs. Mature mites are usually less than 1/50” long and are generally found on the undersides of leaves. Mite infestations are often not detected until the plants exhibit damage.

Spider mite	Spider mite damage

Mites have needlelike, piercing mouthparts that puncture the leaf and suck the plant juices. Damage from light infestations appears as yellow or gray stippled patterns on the leaves. The undersides of infested leaves usually have fine, silken webbing spun across them. Heavy infestations cause the leaves to turn yellow, gray or brownish and eventually drop off. Webbing may be spun over entire branches or, in the case of small plants, over the entire plant.

When the undersides of the leaves are examined closely with a 10X to 25X power magnifying glass, the small mites can be seen. The body contents sometimes show through their transparent body walls, giving them a spotted appearance. Cast skins may also be seen among the live mites.

The adult female lays several hundred eggs during her life. The eggs hatch in about three days. Immature mites molt three times before reaching the adult stage. Under optimum conditions (85º F), mites complete their development from egg to adult in seven to 10 days. There are many overlapping generations per year.

Spider mites are frequently found on azalea, camellia, chrysanthemum, citrus, ligustrum, orchid, pyracantha, rose, viburnum, and bedding plants. They are also a persistent pest of interior foliage plants. Mite damage is much more severe during dry weather.

Lacebugs

Lacebugs are small, broad flat insects about 1/8” long. Their bodies are usually brown and wings are clear with a fine, lacy appearance. Lacebugs have piercing-sucking mouthparts.

Damage appears on the top side of the leaf as a whitish speckling which is caused by the insects feeding on the underside of the leaf. Shiny black spots of excrement on the undersides of leaves are a good indicator of lacebug infestation. The most prevalent lacebug species are the azalea, hawthorn, pyracantha and sycamore.

Lacebug	Lacebug damage

Aphids

Aphids, or “plant lice,” may infest almost any plant. They are most common on camellia, crepe myrtle, gardenia, hibiscus, ixora, oleander, palm and rose as well as nearly all bedding and foliage plants. Aphids have piercing-sucking mouthparts and cause damage by sucking plant juices. However, their ability to transmit plant viral diseases may be more harmful than any direct feeding damage.

Aphids

Aphids are soft bodied, pear shaped insects. They are generally less than 1/8” long and are usually green, but many aphids are black, brown, pink, yellow or blue. Aphids are commonly found on young, developing leaves and stems in clusters or colonies of individuals. Their feeding distorts a plant’s new growth, and the leaves curl. Most aphids are wingless, but when colonies become overcrowded, winged forms are produced. The most distinguishing feature when identifying aphids are the two short tubes, or cornicles, that extend from the rear of the body.

Aphid damage

Aphids are unlike most insects. Almost all aphids are female, reproduce without mating and seldom lay eggs, instead giving birth to live young. Aphids can reproduce rapidly and produce many generations in a year. Each female aphid produces 50 to 100 daughters during her life and each daughter begins reproducing in six to eight days.

Scale

On many ornamental plants, scale insects are the most serious pests. Scales damage plants by sucking juices from them. Heavily infested plants appear unhealthy and produce little new growth.

Scales feeding on the undersides of leaves may cause yellow spots to appear on the top sides. These spots become large as the scales continue to feed. If the scales are not controlled, leaves will drop prematurely, sometimes killing portions of twigs and branches. Scales also feed on trunks and stems of plants.

Female scales never have wings and are disseminated primarily by infested plant stock. They are spread to a lesser extent in the crawler stage by man, birds, other animals and wind currents.

Scales are divided into two groups: (1) armored scales, and (2) soft scales. The armored scales secrete a waxy covering over their bodies. This covering is not an integral part of the insect’s body, but the scale lives and feeds under this cover that resembles a plate of armor. They vary in size from 1/16” to 1/8” in diameter and can be almost any color, depending on the species. Armored scales may be circular, oval, oblong, threadlike or pear-shaped. The female armor is larger than that of the male, while the shape and color may be similar to distinctly different, depending upon the particular species.

Examples of armored scales are the tea scale, Florida red scale, false oleander scale, oleander pit scale and white peach scale.

Tea scale damage	Tea scale

Soft scales also secrete a waxy covering that is an integral part of their body. Soft scales vary widely in color, size and shape. They range from 1/8” to 1/2” in diameter, and may be nearly flat to almost spherical. Examples of soft scale are hemispherical scale, green scale, pyriform scale and Florida wax scale.

Florida Wax Scale

Sooty mold

Sooty mold is a black fungus that grows on the excretion (honeydew) of aphids, mealybugs, soft scales and particularly that of immature whiteflies. This fungus detracts from the beauty of ornamental plants and reduces their photosynthetic activity. Sooty mold can be washed off the leaves with soapy water, or horticultural oil.

Sooty mold

Tropical sod webworm

This is the most common caterpillar attacking turfgrass. They attack all grasses, but Bermuda is preferred and Bahia is least desirable. The larvae are greenish with numerous black spots and are 3/4 ” long when mature. Sod webworms are usually not a problem until August in north Florida. Injured grass has notches chewed along the sides of the blades or is eaten back unevenly. They feed only at night and rest in a curled position on the soil surface during the day. The life cycle requires five to six weeks and there are several generations per year.

Tropical sod webworm larva	Sod webworm damage

Twolined spittlebugs

Adults are 1/4” long, and black with two reddish-orange, transverse bands on the wings. Eggs are laid in the thatch. The nymphs are white and live within a mass of frothy “spittle” they secrete on the grass. The life cycle requires two and one-half months and there are two generations per year. Both adult and nymphs withdraw plant sap with their piercing-sucking mouthparts. Damaged grass tips are yellowish, and eventually curl and turn brown.

Spittle mass	Spittlebug adult