By Evan Anderson, Walton County Agriculture Agent:
Gardening is an attractive pastime, not only for homeowners but also, it seems, for every critter out there that wants a free meal. If a gardener isn’t trying to keep deer, rabbits, or moles out of their crops, they’re fighting against insects of many
Aphids come in many colors, but are a common (and unwelcome) sight on garden plants. Photo courtesy Evan Anderson.
different sorts. With as many different sorts as there are, it can be dizzying to try and keep track of them and to figure out what’s doing damage to which vegetables.
Just because you see an insect in your garden doesn’t mean it’s a bad one. There are many that can be friends to a gardener, patrolling the plants to snack on pests. It’s important to know what you’re looking at before you try to control them; you might end up killing off a helpful bug instead of one that’s a problem!
It can be helpful to look at the damage done by the insects that are plaguing your garden to figure out what kind they are. Piercing / sucking insects drink the fluids from inside plant tissues, and leave small dots or stippling marks, and may exude honeydew, a stick fluid that sometimes grows sooty mold on
Honeybees are an example of a good bug to find in your garden. They help pollinate crops. Photo courtesy Evan Anderson.
it. These bugs include aphids, scales, mealybugs, spider mites, stink bugs, and thrips.
Chewing insects are those that usually go after plant leaves. They chew holes, and if an infestation is bad, they might defoliate a plant very quickly! Caterpillars, grasshoppers, and some beetles are the worst offenders of this sort.
If you need help identifying or figuring out how to control an insect in your garden or any other horticultural topic, feel free to contact your local UF/IFAS Extension office!
An example of damage from piercing/sucking insects. Photo courtesy Evan Anderson.
Damage caused by azalea lace bug, Stephanitis pyrioides (Scott), feeding. Photograph by James. L. Castner, University of Florida. Severely damaged leaves become heavily discolored and eventually dry or fall off. Symptoms may sometimes be confused with mite injury, but the presence of black varnish-like excrement, frequently with cast skins attached, suggest lace bug damage (Johnson and Lyon 1991).
You may be noticing the color disappearing from your azaleas right now. Do your azaleas look bleached out from a piercing-sucking insect. The culprit is probably azalea lace bug, Stephanitis pyrioides. This pest overwinters in eggs on the underside of infested leaves. 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 foliage detracts greatly from the plant’s beauty, reduces the plant’s 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).
Adult azalea lace bug, Stephanitis pyrioides (Scott), and excrement. Photograph by James. L. Castner, University of Florida.
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.
Nymphs of the azalea lace bug, Stephanitis pyrioides (Scott), with several cast skins and excrement. 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.
For more information go to: http://entomology.ifas.ufl.edu/creatures/orn/shrubs/azalea_lace_bug.htm
An adult firefly showing off its characteristic beetle wings and bioluminescent abdomen. Credit: Art Farmer, Creative Commons.
Many of us have memories of warm summer nights watching fireflies. Some of us might have even chased and caught a few to put in mason jars for observation, fascinated by their glowing abdomens. Floridians have the best chance to see these unique insects, as we have more known species than any other state. Recently, I’ve had many folks say that they see less fireflies these days, which got me looking into how these creatures live and what researchers know about their numbers.
Fireflies are actually a type of beetle in the Lampyridae family. They go through complete metamorphosis, meaning their immature larvae look completely different than the adults. A very unique characteristic of the family is the ability to produce light, known as bioluminescence. They do this in a very efficient way, creating very little heat, through the reaction of luciferin and luciferase along with oxygen, some energy, and other compounds. These light-producing compounds serve a dual purpose, warding off predators and attracting mates. The larvae of all Lampyridae benefit from the offensive taste of the compounds while only some adult Lampyridae use bioluminescence to attract mates. Each species of firefly has specific patterns of flashes. Males have the showiest light displays while females use more conservative light shows to signal back to potential mates.
Firefly larvae taste bad to predators due to the compounds that produce light. Credit: Gerald J Lenhard, LSU, bugwood.org.
Larvae of fireflies live in the soil and feed on slugs, snails, earthworms, and other soft-bodied insects. The larvae develop in the soil during cooler months, preferring moist habitats, and emerge as adults in the late spring to early summer. Some species may emerge in the early spring. Adult fireflies feed on nectar and honeydew, though some females prey on smaller firefly species by fooling males close to them through light signaling. Adults with the ability to produce light are active at night, while non-bioluminescent adults are active during the day.
An adult firefly. Credit: Mirko Schoenitz, iNaturalist.org.
Entomologists specializing in fireflies have raised the concern that these classic summer-time insects are in decline. Reasons for the decline are associated with increased urbanization. Loss of suitable habitat and increased pesticide use, including broad-spectrum insecticides for home lawn insect control, negatively affect firefly larvae living in the soil. Researchers also point to urban light pollution as another cause. The ever-glowing night sky in populated areas, originating from house lights, ball fields, parking lots, and roadways, disturb firefly communication and reproduction.
UF/IFAS infographic about fireflies. Credit: UF/IFAS.
Homeowners can help fireflies by leaving small patches of unmanaged landscaped areas, such as along property lines, and only using insecticides when absolutely necessary. If pesticides are needed to control lawn and garden pests, the use of more selective, low-toxicity products is preferable. Turning off unnecessary outdoor lighting is another step homeowners can take to encourage firefly populations. Residents of homeowner associations can work together to minimize excess lighting community-wide, saving electricity and maybe even fireflies.
For more information on fireflies and best practices to control lawn and garden pests, contact your local county extension office.
Adult and nymphs of mole crickets. Photo: Julie McConnell, UF/IFAS
The best time to treat for mole crickets is during June through July. But don’t treat at all if mole crickets have not been positively found and identified in the affected lawn areas.
Don’t worry about the adults that are seen flying around lights in the evenings or about the mole crickets found dead in swimming pools this time of year. They are in a mating phase and are doing very little to no damage to lawns during late winter and spring.
We can take advantage of the fact that there’s only one generation per year in North Florida. The eggs will have all hatched by mid to late June. At that time, you’re dealing with young mole crickets that can’t fly and that are much more susceptible to the insecticides designed to kill them. Mole crickets spend winter as adults in the soil. In late February and March, adults emerge and begin mating. Shortly after mating, males die and females fly to suitable areas for egg laying. Mated females deposit eggs in tunnels. After depositing her eggs the female dies. Attempting to control adult mole crickets during this mating period a waste of time, money and product. Plus, adult mole crickets are difficult to control and can easily fly out of treated areas.
You can easily determine if mole crickets are the cause for your lawn problem by flushing them out with a soap and water mixture.
Mix 1½ ounces of a lemon scented liquid dish-washing 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. It only takes several minutes for mole crickets to crawl to the surface after the soap treatment if they are present. Repeat the process around the yard where you suspect mole cricket problems. If you flush an average of two to four crickets are flushed out per site, control may be needed.
There are a number of insecticides on the market to control mole crickets. But before using any product, first identify the problem as mole cricket damage by using the soap flush technique. Then choose a lawn insecticide that lists mole crickets on its label. And finally read the label carefully for use directions, application techniques, irrigation requirements and precautions.
For more information on mole crickets, including recommended insecticides and other non-chemical control options, contact the UF/IFAS Extension Office in your County or access the following links.
Insect Pest Management on Turfgrass
Mole Cricket IPM Guide for Florida
Spring is a wonderful time of year. After months of dreariness and bare branches, bright, succulent green leaves and flowers of every kind and color have emerged. So too, have emerged gardeners and outdoor enthusiasts ready to tackle all their home and landscape improvement projects planned over the winter. However, this is also the time, when folks first start paying attention to their plants again, that strange, seemingly inexpiable plant problems crop up!
All plant problems can be divided into two categories: biotic problems, or issues caused by a living organism (think insects, fungus, and bacteria), and abiotic problems, issues that arise from things other than biotic pests. It’s the first category that people generally turn to when something goes wrong in their landscape or garden. It’s convenient to blame problems on pests and it’s very satisfying to go to the local home improvement store, buy a bottle of something and spray the problem into submission. But, in many of my consultations with clientele each spring, I find myself having to step back, consider holistically the circumstances causing the issue to arise, scout for pests and diseases, and if I find no evidence of either, encouraging the person to consider the possibility the problem is abiotic and to adopt patience and allow the problem to correct itself. Of course, this is never what anyone wants to hear. We always want a solvable problem with a simple cause and solution. But life isn’t always that easy and sometimes we must accept that we (nor a pest/disease) did anything wrong to cause the issue and, in some cases, that we ourselves actually caused the problem to happen in the first place! To illustrate, let’s consider two case studies from site visits I’ve had this spring.
Cold damage on Boxwood hedge
Three weeks ago, I got a call from a very concerned client. She had gotten her March issue of a popular outdoor magazine in the mail, in which was a feature on an emerging pathogen, Boxwood Blight, a nasty fungus decimating Boxwood populations in states north of us. She had also noticed the Boxwoods in front of her house had recently developed browning of their new spring shoots across most the hedgerow. Having read the article and matching the symptoms she’d noticed to the ones described in the magazine article, she was convinced her shrub was infected with blight and wanted to know if there was a cure. Agreeing that the symptoms sounded similar and wanting to rule out an infection of an extremely serious pathogen, I decided to go take a look. Upon inspection, it was obvious that Boxwood Blight wasn’t to blame. Damage from disease generally isn’t quite as uniform as what I saw. The new growth on top of the hedge was indeed brown but only where the eaves of the house and a nearby tree didn’t provide overhead cover and, to boot, the sides of the hedge were a very normal bright green. Having gone through a recent cold snap that brought several mornings of heavy frost and knowing that the weeks before that the weather had been unseasonably warm, causing many plants to begin growing prematurely, all signs pointed toward an abiotic problem, cold/frost damage that would clear up as soon as the plant put on another flush of growth. The client was delighted to hear she didn’t have a hedge killing problem that would require either adopting a monthly fungicide regime or replacing the hedge with a different species.
Damage to ‘Sunshine’ Ligustrum from pressure washing siding with bleach.
The very next week, another client asked if I would come by her house and take a look at a hedge of ‘Sunshine’ Ligustrum that lines her driveway, whose leaves had “bleached” out, turning from their normal chartreuse to a bronzy white color. This time, having seen similar issues with this particular plant that almost always involved an infestation of Spider or Broad Mites, I figured this was a cut and dry case that would end with a call to her pest control company to come spray the offending bugs. However, though the leaf damage looked similar, I was not able to locate any existing pests or find evidence any had been around recently, rather it appeared the leaves had been exposed to something that “bleached” and burned them. Puzzled, I began asking questions. What kind of maintenance occurs on the plants? Have you fertilized or applied any chemicals recently? Nothing. Then, near the end of our conversation, the client mentioned that her neighbor had pressure washed their house on a windy day and that she was irritated because some of the soap solution had gotten on her car. Bingo. Leaf burn from pressure washing solution chemicals. This time I was guilty of assuming the worst from a pest when the problem quite literally blew in on the wind from next door. Again, the client was relieved to know the plant would recover as soon as a new flush of growth emerged and hid the burned older leaves!
This spring, I’d encourage you to learn from the above situations and the next time you notice an issue on plants in your yard, before you reach for the pesticides, take a step back and think about what the damage looks like, thoroughly inspect the plants for possible insects or disease, and if you don’t find any, consider the possibility that the problem was abiotic in nature! And remember, if you need any assistance with identification of a landscape problem and want research-based recommendations on how to manage the problem, contact your local UF/IFAS Extension office.
One of the interesting ants that I am seeing more commonly in landscape settings is the Trap jaw ant (Odontomachus sp.). This ant is so named because of it’s large mandibles (mouthparts) that spring shut capturing prey. These mouthparts can also be used as a defensive mechanism allowing the ant to spring away from something it encounters.
Trapjaw ants. Photo by MSU Ag Communications/Kat Lawrence
A nesting area is very recognizable after you have seen one because it looks like a collection of soil and small wood debris piled at the base of plants or old stumps. I have encountered nesting areas around living shrubs in many mulched areas of the landscape and under pots sitting on old tree stumps.
Nesting debris from the Trapjaw ants at the base of a Princess flower. Photo by Beth Bolles, UF / IFAS Extension Escambia County.
My first experience with the trap jaw ant was not very pleasant. I was working in a mulched area pulling a few weeds without gloves. I unknowingly disturbed the nest and received a pain sting similar to a paper wasp sting. The discomfort was short-lived and I personally did not have inflammation or inching a few minutes later. Of course, I identified the ant and have since become very familiar with recognizing nesting spots.
Although trap jaw ants are not native to our area, they do not rank in the same category as fire ants which are both economically and medically problematic. Since trap jaw ants are currently found in more natural areas of the landscape, homeowners should just be aware of their presence. Consider a pair of gloves or garden tools when rooting around in mulch. When a nesting area is disturbed, the large ants (about .5 inches) will be easy to observe as one of the more interesting ants we may encounter.