by Eddie Powell | May 8, 2015
Florida soft scale. Photo credit: UF/IFAS.
Scale insects are one of the most serious problems homeowners face on ornamentals this time of year. The most common are armored scale, soft scale, and mealybugs. They cause damage by sucking plant fluids from the leaves, stems, and sometimes roots. Some species feed on the underside of the leaves which can appear as yellowing spots or chlorotic lesions. Heavy infestations can cause extensive leaf yellowing, premature leaf drop, branch dieback, and plant death.
The life cycle starts when the eggs are laid beneath a waxy covering or beneath the adult female. After the eggs hatch two to three weeks later, the nymphs (crawlers) move around the plant until they find a suitable feeding site. Crawlers then insert their straw-like mouthparts into the plant and begin to feed and grow. The male often develops wings and flies to locate a mate.
Armored scale nymphs. Photo: UF/IFAS.
Armored scale is distinct from other types of scales because they secrete a waxy covering over their body that is not attached to the body. The scale lives and feeds under this covering ranging 1/16 to 1/8 inch in size. They can be any color or shape, depending on the species. Armored scale does not produce honeydew.
Armored scale. Photo credit: UF/IFAS.
Soft scale also secretes a waxy covering but it is attached to the bodies. Soft scales vary in color, size, and shape. They are circular shaped and range from 1/8 to ½ inch in diameter. Because they consume so much plant sap, they excrete a lot of sugary liquid called honeydew. Honeydew is the sticky liquid found on the leaves.
Mealybugs. Photo credit: UF/IFAS.
Mealybugs are soft bodied insects that are often covered with cottony white filaments. They are 1/8 inch in size and feed on all parts of plants. Injured plants have discolored, wilted, and deformed foliage.
Sooty mold is caused when mealybugs and soft scales excrete large amounts of honeydew which provides an excellent medium for the growth of the black fungus. Sooty mold is not only unattractive; it slows down the growth of the plant as it interferes with photosynthesis. Over time, with the control of the insect population, the sooty mold will weather away. Ants can also play a big factor in controlling sooty mold as they will feed on the honeydew.
Sooty mold. Photo credit: UF/IFAS.
To control scale and mealybugs, avoid over-fertilizing and monitor your plants often. If the infestation becomes over-bearing, spray a fine mist of Horticultural Oil on the foliage. Avoid spraying in the summer heat because of damaging foliage. Other chemicals that can be used if necessary are Sevin dust and Malathion.
by Larry Williams | Apr 20, 2015
Mole cricket tunnels. Credit: N. Leppla, UF/IFAS
Many people treat their lawn with an insecticide when they see mole crickets in the spring or at the first sign of a brown area in their lawn. What they don’t understand is the biology of this pest.
Mole crickets spend the winter as adults in the soil. As temperatures warm in late February and March, adult mole crickets emerge and begin to mate. Male mole crickets construct a chamber in the soil and chirp to attract female crickets. Attracted females fly to the males. After mating, males die and females fly to a suitable area for egg laying. Mated females begin tunneling and laying eggs in the tunnels. They lay about four clutches of eggs in different areas, averaging 35 eggs per clutch. Female crickets die shortly after laying their eggs.
Use of insecticides during early spring is not recommended because:
- adult mole crickets are not easily killed
- they cause minimal lawn damage during the mating and egg laying process, and,
- reinfestation from subsequent flights is likely.
The best time to treat for mole crickets is during mid-June through July. This will be when eggs have hatched but before the nymphs (immature mole crickets) are large enough to do much damage. Proper timing of the insecticide application is very important to achieve control.
Mole cricket nymphs. Credit: J. Castner, UF/IFAS
If you are not sure if mole crickets are present, you can find out with a soap solution. Mix 1½ fluid ounces of a lemon scented liquid dishwashing soap in two gallons of water in a sprinkling can or bucket. Pour the soapy water over an area approximately four square feet and count the number of mole crickets that emerge. If they are present, it only takes several minutes for mole crickets to crawl to the surface after the soap treatment. Repeat the process around the yard where you suspect mole cricket problems. If you flush an average of two to four crickets per site, treat the lawn with an insecticide. Follow up with spot treatments if any crickets escape the first insecticide treatment. But don’t treat at all if there is no evidence of mole cricket activity.
There are a number of products for mole cricket control in home lawns. Look for insecticides that contain the following active ingredients: bifenthrin, carbaryl, cyfluthrin, deltamethrin, imidacloprid , lambda-cyhalothrin or permethrin.
Before using any product for mole cricket control first identify the problem as mole cricket damage by using the soap flush technique. Then choose an insecticide that lists mole crickets on its label. And finally, read the container carefully for use directions, application techniques, irrigation requirements and precautions.
by Beth Bolles | Jan 13, 2015
The Chinese privet, Ligustrum sinense, is a plant that is well known to many people as a great nuisance in the landscape. It is also a Florida noxious weed because of its invasive nature.
Originally grown as an ornamental that formed a hedge and tolerated poor conditions, the Chinese privet has now spread to natural areas and grows easily on disturbed soils. Plants are full of white fragrant flowers in the spring with abundant small black fruit forming late summer and remaining into the winter. Seeds are easily spread by wildlife to new areas but new plants can also grow from roots.
Privet may be best identified when it is in bloom.
Chinese privet easily forms a thicket, shading areas and impacting the growth of native plants. Homeowners can identify any plants growing on their property and work to manage Chinese privet when plants are not in seed. If you need assistance in identification, contact your local Extension office or view pictures online.
Even though homeowners will not find Ligustrum sinense in the nursery, cultivars of this plant may be found. One newer selection is ‘Sunshine’. This is a reportedly sterile cultivar that grows much smaller and has yellow foliage. Homeowners who choose to install ‘Sunshine’ may still need to be cautious since there has not been extensive research in Florida to verify that it will not become a future issue.
by Alex Bolques | Jun 17, 2014
Homeowner accounts of white fluffy woolly masses on woody ornamentals have been on the rise. They can appear on the ends of a wide variety of woody ornamental branches in the landscape. A closer inspection of these white woolly masses can provide the curious observer with a startling surprise. “It’s Alive!” It moves and seems to jump at you, most likely jumping away from you. Once you have recovered from the mildly frightful encounter, you ask yourself, “What was that?”
Adult citrus flatid planthopper, Metcalfa pruinosa
(Say). Credits: Photograph by: Lyle J. Buss, University of Florida
They are planthoppers (Metcalfa pruinosa), an insect in the order Hemiptera. The common name for this woolly looking planthopper is the citrus flatid planthopper (CFP). As the name implies, they occur on citrus but can also be found on many woody ornamentals and fruit trees. The adult planthopper wing arrangement is tent-like, meaning that the forewings are held over the insect abdomen in a tent configuration.
Nymph of the citrus flatid planthopper, Metcalfa
pruinosa (Say). Credits: Photograph by: Lyle J. Buss,
University of Florida
The nymph, young immature insect, produces the white woolly material that is characteristic of CFP. At first sight, they can be mistaken for mealy bugs, which may look similar since they are covered with cottony white filaments. They can also be mistaken for cottony cushion scale.
Mealybugs. Credits: James Castner, University
of Florida
Cottony cushion scales, Icerya purchasi, on twig.
Credits: James Castner, University of Florida
In both of these cases of mistaken identities, the insect will not jump or hop around. No chemical control is necessary although sooty mold can occur on heavily populated plants. In that case, a soapy water treatment can be applied.
Follow these links to more information on the citrus flatid planthopper, mealy bugs, and cottony-cushion scale.
by Larry Williams | Jun 3, 2014
Glistening webbing formed by tree cattle (psocids) Photo credit: Doug Caldwell, University of Florida
Many people are noticing small insects on trunks and branches of their trees. When disturbed, these insects move in a group and are commonly called tree cattle because of this herding habit. They are ¼ inch brownish-black insects with white markings.
Some people assume that these insects will injure their trees but they are harmless. They could be considered beneficial.
These insects are called psocids (pronounced so-cids). They have numerous common names including tree cattle and bark lice. They feed on lichen, moss, algae, fungi, spores, pollen and the remains of other insects found on the tree’s bark. As a result, they are sometimes referred to as bark cleaners.
Tree cattle may form webbing. This webbing is tight against the tree’s trunk and/or limbs. It appears suddenly. The webbing is used as a protection from weather and predators. Underneath you may find psocids.
The glistening webbing may attract a person’s attention resulting in the tree being visually inspected from top to bottom. A dead branch or other imperfections in the tree may be noticed and then wrongly blamed on the tree cattle. I’ve talked to homeowners that sprayed their trees with insecticides or that hired pest control businesses to treat the trees as a result of finding the webbing/psocids. One person told me that he cut down a tree after finding tree cattle. He wrongly assumed that these insects were pests that might move through the area and kill trees. He thought he was doing a good thing.
Adult female psocids lay eggs in clusters on leaves, branches and tree trunks. After hatching, the immature insects (nymphs) remain together under their silk webbing. Adults have wings which are held roof-like over their body. Nymphs are wingless. Psocids usually have several generations per year in Florida.
After seeing the webbing and/or insects, many people insist on spraying insecticides because they believe these insec
Under the webbing live hundreds of psocids. Photo credit: UF/IFAS Jim Castner
ts are damaging their trees. But as mentioned, they are bark cleaners and do not damage trees. If the silk webbing is considered unsightly, a heavy stream of water from a garden hose can be used to wash insects and webbing off infested trees. If nothing is done, the webbing usually goes away in several weeks.
Psocids can be found on many rough-barked hardwood trees and palms. Occasionally, they may be found on wood siding, fence posts or similar areas.
