Insects use pheromones to attract their mates and communicate with each other. Ants use pheromones to tell fellow ants where to find food. Aphids use pheromones to warn each other about potential predators. And all insects use pheromones to call for a mate.
So what exactly are pheromones? Pheromones are substances that are secreted by an individual and received by another individual of the same species. In humans, pheromones are most commonly found in sweat and detected by the olfactory system. Most animals have a functioning vomeronasal organ inside their noses to detect and process pheromones. However, it is debatable whether adult humans possess a functional vomeronasal organ.
Although most of us may not be able to detect insect pheromones, scientists have been able to identify and synthesize the pheromones of many economically important insects. These pheromones are impregnated on rubber and plastic dispensers and placed in different types of traps depending on the pest. The pheromone traps attract males of the target species. These traps are commonly used for monitoring, but in some cases can be utilized to disrupt mating habits which can help control some pests.
The most common pheromone trap in this part of the country is probably a boll weevil trap. Growing up, I thought they looked like little green lighthouses. These traps consist of a yellow-green cannister with an inverted funnel on top that contains the pheromone. While you may not be growing cotton in your home garden, there are some other common insect pests you may want to monitor and possibly disrupt.
Pecan Nut Casebearer (PNC) – These moths are gray with a dark line of scales on their forewings. PNC moths are about 1/3 inches long. They lay their eggs on the outside of pecan husks in April/early May. Their larvae bore into the base of developing nuts and remain inside the nuts for four to five weeks to feed then pupate. A tent-type trap with pheromone can be hung in a pecan tree in April or May to help monitor for this insect. Depending on how many trees you have, multiple traps can be installed to possibly disrupt the mating cycle of this pest.
Asian Citrus Psyllid (ACP) – These tiny insects are about the size of the tip of a pencil (about 1/8 inches long). They vector the Huanglongbing (HLB) disease also known as citrus greening. This disease blocks the nutrient uptake tissue of citrus trees and eventually kills infected trees. Traps consist of a yellow sticky card with a pheromone bait sometimes impregnated on the twist tie hanger. The citrus industry has been heavily impacted by citrus greening, so monitoring for this pest is very important.
Clearwing Moth – There are numerous species of clearwing moths that bore into the trunks of fruit and ornamental trees and shrubs. One of the most common is the peachtree borer. These insects don’t look like a typical moth. Instead, they resemble wasps. Tent-type pheromone traps can be used to monitor for clearwing moths and potentially disrupt their mating habits. Another common clearwing moth is the ash borer (lilac borer). As their name would suggest, these moths bore into the wood of ash trees, but they also like various Ligustrum species and olive trees.
These are just a few of the species of insects that can be monitored by pheromone traps. To help with the timing of trap dispersal and placement, you should get a grasp of concept of “Degree Days”. Degree day accumulation is used to predict important life events for particular insects such as the average egg laying date, egg hatch date, and larval development. More information on calculating degree days can be found in the article “Predicting Insect Development Using Degree Days” from the University of Kentucky. Fortunately for us, we can skip some of the math by utilizing the AgroClimate Growing Degree Days Calculator. Simply select the weather station closest to you on the provided map and a graph will appear.
Welcome to the world of symbiotic serenity, where ants and aphids work in harmony to create a thriving ecosystem. Ants farming aphids is a fascinating phenomenon in nature, where ants tend to aphids, protecting and nurturing them like precious livestock, while aphids provide the ants with a sweet and nutritious honeydew secretion.
The relationship between ants and aphids is complex and benefits both parties. Aphids, which are soft-bodied sucking insects that feed on plant sap, secreting honeydew – a sugary secretion that aphids produce as waste from their sap consumption. This sweet substance is highly attractive to ants, who actively tend to aphids in order to obtain honeydew as a food source.
One of the most fascinating aspects of ant farming aphids is the behavior exhibited by ants when caring and protecting aphids. Ants are known to carefully tend to aphids, often referred to as “herding”. In doing so, they stroke the aphids with their antennae, stimulating them to release honeydew. Ants then collect and consume this honeydew, which serves as a valuable source of nutrition for them.
Aphids also benefit from this mutualistic partnership by relying on ants for protection from predators such as ladybugs, lacewings, and other aphid predators. In the presence of ants, aphids are less likely to be attacked by natural enemies, which allows them to feed and reproduce more freely. In addition, ants can transport aphids to new feeding sites, which helps aphids access fresh sources of sap.
However, this mutualistic relationship between ants and aphids can also pose problems for gardeners and homeowners. When ants protect aphids from natural enemies, this can result in increased aphid populations and plant damage. Therefore, it is important to control ant farming of aphids in order to manage aphid infestations effectively.
There are several methods gardeners/homeowners can use to manage ant farming of aphids:
Early detection is key. Regularly check for aphids at least twice a week while plants are growing rapidly.
Utilize natural enemies of aphids such as parasitic wasps, lady beetles, lacewing larvae, soldier beetles, and syrphid fly larvae. These insects can help keep aphid populations at an acceptable threshold.
Ant management is crucial. A band of sticky material can be wrapped around the trunk to prevent ants from reaching the aphids.
Prune and dispose of infested branches.
Insecticidal soaps and oils can be used to suffocate aphids. However, these products only kill aphids on contact. Other synthetic insecticides like malathion, permethrin, etc. are alternatives that can control aphids, but they may harm natural enemies and pollinators such as bees.
*Important to note, follow all manufacturers instruction when using chemical products.
In conclusion, ants farming aphids is a captivating example of mutualistic interactions in nature and serve as a compelling reminder of the wonders and intricacies of the natural world.
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.
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.
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 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.
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.
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.
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/