While the azalea blooms are beautiful, it’s hard to remember what the leaves looked like last summer. But, if you look carefully, you may see some off-colored, bleached out leaves. Those are from a piercing-sucking insect. Its azalea lace bug, Stephanitis pyrioides. They overwinter as eggs on the underside of infested leaves or in the leaf litter or mulch under the shrub. Eggs hatch in late March and early April. The insect then passes through five nymphal instars before becoming an adult. It takes approximately one month for the insect to complete development from egg to adult and there are at least four generations per year. Valuable plants that are susceptible to lace bug damage should be inspected in the early spring for the presence of overwintering lace bug adults, eggs and newly hatched nymphs. Inspect these plants every two weeks during the growing season for developing lace bug infestations.
Damage caused by azalea lace bug, Stephanitis pyrioides (Scott), feeding. Photograph by James. L. Castner, University of Florida.
Both adults and nymphs have piercing-sucking mouthparts and remove sap as they feed from the underside of the leaf. Lace bug damage to the foliage detracts greatly from the plants’ beauty, reduces the plants’ ability to produce food, decreases plant vigor and causes the plant to be more susceptible to damage by other insects, diseases or unfavorable weather conditions. The azalea can become almost silver or bleached in appearance from the feeding lace bug damage.
Adult azalea lace bug, Stephanitis pyrioides (Scott). Photograph by Jamba Gyeltshen, University of Florida.
However, lace bugs often go undetected until the infested plants show severe damage sometime into the summer. By then several generations of lace bugs have been weakening the plant. Inspecting early in the spring and simply washing them off the underside of the leaves can help to avoid damage later and the need for pesticides.
Adult lace bugs are flattened and rectangular in shape measuring 1/8 to 1/4 inch long. The area behind the head and the wing covers form a broadened, lace-like body covering. The wings are light amber to transparent in color. Lace bugs leave behind spiny black spots of frass (excrement).
Lace bug nymphs are flat and oval in shape with spines projecting from their bodies in all directions. A lace bug nymph goes through five growth stages (instars) before becoming an adult. At each stage the nymph sheds its skin (molts) and these old skins often remain attached to the lower surface of infested leaves.
Azalea leaf with azalea lace bugs, Stephanitis pyrioides (Scott), and excrement spots. Photograph by James. L. Castner, University of Florida.
Azalea lace bug eggs are football-shaped and are transparent to cream colored. Lace bug eggs are found on the lower leaf surface, usually alongside or inserted into a leaf vein. Adult females secrete a varnish-like substance over the eggs that hardens into a scab-like protective covering. Other plant species, such as lantana and sycamore, may have similar symptoms. But, realize that lace bugs are host specific. They feed on their favorite plant and won’t go to another plant species. However, the life cycle is similar. Be sure to clean up all the damaged leaves. That’s where the eggs will remain for the winter. Start next spring egg-free.
The Multicolored Asian lady beetle (Harmonia axyridis) was introduced from Asia and intentionally and quickly established itself over the entire United States.
A Comparison
The Multicolored Asian Lady Beetle (MALB) adults can be distinguished from other lady beetle species by a pair of white, oval markings behind the head that form a black M-shaped pattern. Most adults have nineteen black spots on their forewings, but variability is common and spots may be missing. Adult MALBs consist of several color patterns (morphs), varying from solid orange to red with black spots.
This species is often mistaken for the seven spotted lady beetle (Coccinella septempunctata), which was introduced from Europe. Both species are usually found feeding on the same insect host and plants.
Photographer: James Castner, University of FloridaPhotographer: Russell F. Mizell, University of Florida
Both species tend to overwinter in large numbers. However, the Seven Spotted Lady Beetle overwinters under rocks, abandoned shrubs and forest edges. In contrast, the MALB is attracted to light and often aggregate and overwinter in dwellings, entering through cracks or crevices.
Due to the onset of winter and scarcity of food, MALB is more noticeable November to January in north Florida. As a result, they are a nuisance during the flight period, aggregating in walls and other parts of dwellings.
Once they enter your dwelling and experience warmth, they fly around and annoyance progresses. They produce a yellow, viscous, foul-smelling defensive substance when disturbed. The defensive substance usually leaves spots on furniture and the foul odor lingers in the air.
The solution
Seal building or caulked entry point to prevent infestation.
If beetles get inside your dwelling, a black light trap can be used.
Vacuum cleaners can be used to remove them, though, while effective, it will result in some spotting and foul odor.
In conclusion, though a nuisance, lady beetles are considered to be valuable natural enemies and should be tolerated and conserved when possible.
Supporting information for this article can be found in the UF/IFAS EDIS publications:
Citrus is one of the most cherished fruit trees in the Panhandle. Citrus owners are well aware that every year the main damage to their trees come from citrus leafminer (CLM). CLM is a small moth and its larvae feeds between the tissue layers of new leaf growth, causing serpentine mines to form under the leaf cuticle (Fig. 1). The feeding damage results in leaf curling and distortion, and severe infestations of CLM on young trees can retard the growth of trees. Another threat concerning CLM in Florida is that the mines provide an open wound for citrus canker to enter, a bacterial disease that has been found recently in the Florida Panhandle, Georgia, and Alabama.
Most commercial growers deal with CLM in young trees by a soil application of systemic insecticide before the flush season, followed by a foliar insecticide when the systemic drench’s toxicity is declining. Homeowners, however, have limited access to these chemistries. Garden systemic insecticides that include imidacloprid (Bayer’s Tree & Shrub Insect Control™, Merit®, etc.) and dinotefuran (Greenlight Tree and Shrub Insect Control™, Safari®, etc.) are among the few options for CLM control. For the best efficacy, those insecticides should be applied two weeks before the start of the flushing season to allow time for the insecticide to move from the roots into the canopy. To avoid leaching of insecticide away from the root zone, soil applications should be made within a 24-hour period without rain. Citrus trees usually have several flushes per year, depending upon cultivar, climate, and crop load. However, in the Florida Panhandle, most citrus cultivars have two major flushes in May and September.
Importantly, systemic insecticides are only efficient against CLM for small immature trees; therefore, the only products labeled for use against CLM on mature trees are foliar sprays. Horticultural oils or insecticides with spinosad (such as Monterey® Garden Insect Spray) are some options available for homeowners. However, achieving leafminer control with foliar applications on mature trees is challenging due to unsynchronized flushing of trees. Foliar applications should be timed with the appearance of the first visible leaf mines. In any case, be sure to READ THE LABEL and follow all the label directions.
Cultural practices, and non-insecticidal methods.
For isolated trees in a backyard, cultural practices and control through mass trapping are usually sufficient to control CLM and insecticide use is not recommended, especially for mature trees. One of the basic cultural practices is to remove any stems that grow below the bud union or from the rootstock, also called ‘suckers’ (Fig. 2). Those rootstock shoots compete with the scion shoots and are great reservoirs for CLM; removing them will help reducing CLM population. On isolated trees, mass trapping using CLM pheromone provide good results (Fig. 3). The mass trapping method is constituted of a delta trap baited with a lure that emits a large quantity of CLM sex pheromone. CLM males are attracted by the odor and are captured in the delta trap’s sticky liner. Those traps are commonly used by growers to monitor CLM populations, but for homeowners they are sufficient to control CLM on a single tree. This trap and a lure method should protect a single tree for approximately 3 months. Finally, the last option is the use of biological control. Several natural enemies are predators or parasitize CLM. In some case, biological control can reduce CLM populations by 90%. Primary predators of CLM include ants, lacewings, and spiders, as well as a parasitic wasp, Ageniaspis citricola that was introduced into Florida and has become established (Fig. 4).
New growth from the rootstock (called ‘suckers’, red arrow) are a source for CLM infestation and should be removed.
Baited pheromone trap for citrus leafminer (picture Danielle Sprague).
Homeowner accounts of white fluffy woolly masses on woody ornamentals, oak trees and Muhly grass have been on the rise. The good news is they are native insects that need a nursery for their young and will cause little harm to the host plant. The bad news is scientists know very little about the complete live cycle and role in the environment of these insects.
Within the cottony mass there are citrus flatid planthoppers, woolly oak aphids, or Muhly mealybugs. The adults have laid eggs or birthed their young on the leaves. The young nymphs have excreted large amounts of the woolly wax to protect them from predators and weather while they grow larger. Food from the plants is needed to grow, so these piercing-sucking insects are removing sugars from the host plant. But, typically it is not enough to significantly change the plant’s appearance, so most people are not alarmed until they notice “all the white stuff”.
Adult citrus flatid planthopper, Metcalfa pruinosa
(Say). Credits: Photograph by: Lyle J. Buss, University of Florida
The only one that moves quickly are the citrus flatid planthoppers. When a person reaches for the flocked branch, something small moves and seems to jump at you. Most likely the jumping direction is away from you, but it still may be startling. They are planthoppers (Metcalfa pruinosa), an insect in the order Hemiptera. As the name implies, they occur on citrus but can also be found on many woody ornamentals and other fruit trees. The adult planthopper wing arrangement is tent-like, meaning that the forewings are held over the insect abdomen in a tent configuration.
Stegophylla brevirostris Quednau colony on oak. Photograph by Susan E. Halbert
Woolly oak aphids are conspicuous pests on oak (Quercus spp.), because they are covered with large amounts of flocculent wax. Two genera of woolly oak aphids occur in Florida. One species, Stegophylla brevirostris Quednau, is common, and the other, Diphyllaphis microtrema Quednau, is rare. Florida woolly oak aphids are recognized easily by the large quantities of woolly wax that they secrete. Beneath the wax, aphid bodies are pale. Young nymphs are typically pale green, and they tend to be more mobile than adults. The majority of reports of woolly oak aphids indicate a preference for live oak (Quercus virginiana Mill.) as the host. These aphids are live-bearing females. It is not known how these aphids disperse, but possibly they are picked up and carried by birds and larger flying insects because of the sticky wax that surrounds the bodies of the aphids.
Muhly grass infested with mealybug. Photo: Beth Bolles
Muhly grass (Muhlenbergia capillaris) is a generally pest free plant in its native habitat, however, the native mealybug, Stemmatomerinx acircula, has made an appearance on plants in various landscapes. Insects feed on the leaves and are grey with white wax that may have some filaments. You may also see long ovisacs on the leaves which contain eggs and crawlers. With close inspection, you will notice they have legs and can move about.
So “what do you do?’ If the plant doesn’t appear to be suffering, let nature take its course. “This to will pass.” If someone demands perfection, use insecticidal soap to reduce the population. The soft-bodied creatures will dry up before they can become adults. To read more about these odd creatures of nature go to: https://entnemdept.ufl.edu/creatures/
There are numerous insects and insect relatives that can produce webbing, and webbing can be a sign that something unwanted is near. Arachnophobes might grow uneasy at the sight of a spiderweb, and gardeners might frown to see the tiny filaments that spider mites spin. Tree lovers might assume that webs on a tree are a sign that caterpillars such as the eastern tent caterpillar have taken up residence. But what about webs on a tree trunk?
Bark louse webbing. Photo courtesy of Evan Anderson.
If you come across a tree trunk coated in silk, chances are you’re looking at the work of a bark louse. Also known as psocids or tree cattle, these little insects eat all the stuff that sticks to a tree’s bark. Lichen, moss, algae, and dead bark can all end up as meals for a hungry bark louse. The good news is that while lichens don’t hurt trees, neither do bark lice!
Bark lice spin their webbing as protection from predators. They often produce large quantities of webbing, because there are often large quantities of bark lice present. The name ‘tree cattle’ comes from the fact that they form these large colonies, and move in a manner similar to cattle in groups. While swirling swarms of creepy-crawlies rarely make people feel at ease, don’t worry about these. Acting as a sort of clean-up crew, they will do their work, grow and mature, and move elsewhere by themselves.
There are often several generations of bark lice each year in Florida, so they may reoccur. No control is needed for these insects, though if leftover webbing is considered aesthetically unpleasing it can be removed by spraying with a sharp jet of water. For more information about bark lice, see our EDIS publication at https://edis.ifas.ufl.edu/publication/IN553.
Bark louse nymph. Photo courtesy of Evan Anderson.
It is late summer and many of us enjoy being outdoors in the landscape and taking early morning walks before the temperature rises for the day. There are precautions to take while being outdoors and the activities as many insects are very active, including the yellow jacket. Late summer and many of us being outdoor brings us increases the change of being stung by this insect. The Yellow Jacket sting can be painful and potential dangerous to certain individuals with strong reactions to stings.
Yellowjackets are pollinators and eat caterpillar pests! Credit: Whitney Crenshaw, Colorado State University, Bugwood.org
In the State of Florida there are two species of this Yellow Jacket Wasp, the Eastern Yellow Jacket and the Southern Yellow Jacket. It is difficult to distinguish between them and for this article I will refer to them as Yellow Jackets. Yellow Jackets most often colonize in the ground and are often found in lawns that tend to stay dry, landscape beds and edge of woodlands. Colonies of this flying insect can grow into hundreds or even larger numbers. Often by observation in morning or evening light the entry and exit point of the nest can be see with some luck. It looks like an extremely busy airport with lots of landings and departures. The unfortunate way to find the nest can occur by mowing the lawn disturbing the nest with many yellow jackets emerging from the nest to protect it. The colony quickly goes into defense mode with vibrations occurring nearby. This has occurred with me on more than one occasion. All modesty can be lost while run away from the nesting area with several yellow jackets stinging you move quickly move away. Clothing has been known to be shed to hopefully remove the yellow jackets busily stinging either under or on the outside of clothing.
Southern yellowjacket, Vespula squamosa (Drury), nest dug from ground.
Credit: Gerald J. Lenhard; http://www.insectimages.org/
During the early part of the spring and summer season yellow jackets are busy foraging for protein sources to feed to queen and young larvae. During the consuming of the insects, with many of those harvested being harmful insects to plants. The yellow jackets derive their sugar sources from the larvae secretions as they consume the proteins provided. This is part of the reason we do not often see Yellow Jackets in late spring and early summer. As the queen begins to reduce the amount of egg laying, hence the less numbers of larvae to feed and harvest the sugar for a wasp population at its peak creates a more aggressive need to find alternate sources of sugar. This is part of the reason why yellow jackets show up in greater numbers at outdoor sporting events and other places to look for additional sugar sources. Sugar water for hummingbirds is another backyard site for yellow jackets to work hard for the sugar. Even the birds are careful about approaching the feeders.
I do not advocate the destruction of yellow jacket nesting sites unless they are in proximity to human activity as this can set the situation of stings and potential health challenges for people. If you identify a nest location do not approach and call a company that specializes in addressing these types of stinging insects. Keep in mind that this insect provides a benefit in harvest of many harmful pests to plants yet do pose a potential threat. Be observant as you garden situations that seemed fine last month may have changed quickly.
