Saddleback Caterpillar – Image Credit Matthew Orwat
The reality of what happens deep down in the darkness of a fire ant mound hidden to human eyes or in the tunnels of a mole cricket where only creepy crawly things dare to enter may be too scary to believe.
University of Florida Institute of Food and Agricultural Sciences along with USDA introduced a tiny South American fly to the U.S. to help control the pesky imported fire ant. Literally, these introduced phorid flies cause the imported fire ants’ heads to fall off. They then use the decapitated heads to reproduce. The flies hover above the ants, dive in, latch on to the ant’s body and inject their eggs. The egg hatches, and a maggot wiggles its way into the ant’s head, where it grows for two to three weeks before secreting a chemical that dissolves the membranes holding the ant’s body together. In a few hours the ant’s head falls off. The maggot eats everything in it and then uses it as a pupae case. Gruesome, isn’t it?
Assassin bugs are frequently seen slowly crawling on shrubs in our landscapes. Most are brown to black but many are brightly colored. A common species is reddish-orange in the nymph stage. Assassin bugs feed on many harmful insects. Caterpillars are their favorite food.
They digest their prey before eating it. They do this by piercing their victim with their sharp beak, injecting digestive enzymes. This causes chaos on the unfortunate insect’s nervous system and liquefies the internal organs. The liquefied contents are then consumed, leaving only the shell of its kill. How tragic.
The larra wasp, an introduced predatory insect by University of Florida entomologists, enters a mole cricket tunnel. The female wasp will pounce on the mole cricket, wrestle with it and sting it on its soft underside. This immobilizes the mole cricket long enough to allow the wasp to deposit a single egg on its underside. The mole cricket recovers and burrows back into the ground. The wasp larva eventually hatches and slowly eats the mole cricket alive. Poor mole cricket.
We mere mortals should be aware of these horrifying happenings occurring in our own backyards. And we should be frightened by those people who attempt to kill every six-legged critter in sight because they have wrongly identified them as bad. In reality, less than one percent of all insects that exist are damaging to our plants. Most are of no consequence to our lawns, landscapes or gardens. And many are beneficial.
These beneficial insects are helping us gardeners battle the bad bugs during Halloween and year round.
Plants can become distorted for a wide variety of reasons. Sometimes nutrient deficiencies or toxicities can cause plants to become distorted. Sometimes excessive amounts of water or sunlight can cause plants to become distorted. And sometimes insect feeding damage can be the culprit.
Insects can cause plant mutations by feeding alone or by vectoring disease from one plant to another. The most recent and most detrimental example of insects vectoring disease is the Asian Citrus Psyllid, which has distributed Huanglongbing, also known as citrus greening, to most of the citrus acreage in Florida and across the United States. Fortunately, the panhandle is currently free from this detrimental disorder. However, we still have a plethora of insects that distort plants by one way or another. One group of plant altering insects are commonly known as planthoppers.
Planthopper adults range in size between 1/8 to 1/4 inches long. They are slender and frequently have an angular, pointed head. Coloration depends on species, but generally planthoppers are of green, brown, or white. Immatures look similar to the adults except they are smaller and don’t have wings. Immatures typically feed on the underside of leaves, where the humidity is higher and they are more protected from predators.
Three growth stages of planthoppers. Photo Credit: UF/IFAS Extension
Planthoppers feed on plant leaves and shoots by sucking out the contents. The damage that ensues from feeding depends on the host plant and the hopper species. A few species of hoppers transmit pathogens that can alter plant growth. Usually, adult hoppers are pests only when found in high numbers.
Feeding damage from some species causes small white spots (stippling) to appear on the upper leaf surface, usually beginning near the leaf midrib. Stippled areas eventually merge together into larger whitish blotches. In some plants, feeding damage causes a drying and yellowing (or browning) of leaf tips and some planthopper species cause curling or stunting of newly formed leaves. Oftentimes, white, papery skin castings will remain from the molting process on the undersides of leaves.
Planthopper feeding damage on sweet olive. Photo Credit: UF/IFAS Extension
Planthoppers are rarely present in large enough numbers to cause significant plant damage. Fortunately, planthoppers have many natural enemies including lady beetles, lacewings, damsel bugs, and spiders. Sticky traps are recommended to help monitor planthopper populations. Planthoppers are usually attracted to yellow sticky traps that can be placed among the plant leaves. Small populations can be managed using these traps. If greater populations are present, then insecticidal soap can control young planthoppers. Make sure to spray both the top and underside of the leaves.
Planthoppers are minor pests in the landscape, but they can cause alarming mutations in plant material. Contact your local Extension Office for help with diagnosis and treatment options.
Sometimes when we talk about the size of things we like to estimate and don’t worry too much about being precise, but there are times when as little as a half inch really is a big deal. When talking about landscape maintenance and pest management that half inch can be crucial.
Here are three examples of when less than an inch may be significant.
Bermudagrass lawn cut at half-inch different height. Photo: Julie McConnell, UF/IFAS
Mowing your turf. If you read Mowing Matters last month, you saw mowing height recommendations for common turf types grown in north Florida. We gave a range of heights, but besides referring to the handy chart, you need to pay attention to your specific site. If you begin to mow and the current setting is too low, shut down the mower and adjust the height.
In this picture you can see that just raising the deck up one-half inch prevented the entire yard from being scalped and put under additional stress. After less than a week of proper irrigation the scalped area recovered and the yard looked uniform to casual inspection.
Treating Mole Crickets. The common knee-jerk reaction to seeing adult mole crickets during a mating flight is to treat the lawn. However, when you see the adults they are past the stage of being susceptible to most pesticide treatments. It is also too early to target the next generation – after all you are witnessing mating flights, so time is needed for egg maturation, hatching, and nymph development and feeding before treatment will be effective. Depending on several factors such as temperature and soil moisture nymphs will become active anywhere from 2 weeks to 2 months after adults are seen.
Adult and nymphs of mole crickets. Photo: Julie McConnell, UF/IFAS
Before applying any pesticides, be sure to scout for appropriate life stage (nymphs approximately ½ inch long) and action thresholds of mole crickets by performing a soap flush (details can be found here Mole Cricket IPM Guide for Florida).
Turf Irrigation. It is important to calibrate your irrigation system and make sure that each turfgrass zone is putting out a minimum of one-half inch of water uniformly.
Why this amount? Research has shown that in most Florida soils application of one inch of water will reach the top twelve inches of soil. Healthy turfgrass roots are typically found in the top 4-6 inches of soil, so by applying one half-inch of water per irrigation cycle you should deliver water to turf roots.
To see an example of how to calibrate your system watch this short video demonstration by Dr. Laurie Trenholm, UF/IFAS Turfgrass specialist.
The Zika virus has made us all more aware of the need to avoid getting bit by mosquitoes when we travel to those destinations that have confirmed reports of Zika infected mosquitoes. The Centers for Disease Control and Prevention lists the countries and territories that have travel notices to consult prior to planning a trip or traveling.
The invasive mosquitoes Aedes aegypti (left) and Aedes albopictus (right) occur in the Americas, including Florida, and have been implicated in the transmission of Zika virus. Credit: J Newman, UF/IFAS/FMEL
You should use an insect repellant (following all label instructions) with any of these active ingredients:
DEET
Picaridin
Oil of lemon eucalyptus
Para-menthane diol
IR3535
Wear long-sleeved shirts and pants
Wear clothing that is pre-treated with permethrin or apply a permethrin product to your clothes, but not your skin!
Avoid getting bitten while you sleep by choosing a place with air conditioning or screens on windows and doors or sleep under a mosquito bed net.
According to the Georgia Department of Public Health you should also protect yourself against mosquito bites for at least a week after you return home from any location that has confirmed Zika. You may have an active infection without symptoms that can be spread to others through mosquito bites.
Now let’s talk about mosquito control in your own landscape.
Even though we don’t have confirmed Zika infection in Florida mosquitoes at this writing, mosquitoes in our state can transmit other diseases such as: eastern equine encephalitis, dengue fever, dog or cat heartworm, chikungunya, malaria, St. Louis encephalitis and west Nile virus.
Let’s first explore what kind of environment in your landscape and around your home is friendly to the proliferation of mosquitoes. Adult mosquitoes lay their eggs on or very near water that is still or stagnant. That is because the larvae live in the water but have to come to the surface regularly to breeze. The small delicate larvae need the water surface to be still in order to surface and breathe. Water that is continually moving or flowing inhibits mosquito populations.
Look around your home and landscape for these possible sites of still water that can be excellent mosquito breeding grounds:
bird baths
potted plant saucers
pet dishes
old tires
ponds
roof gutters
tarps over boats or recreational vehicles
rain barrels (screen mesh over the opening will prevent females from laying their eggs)
bromeliads (they hold water in their central cup or leaf axils)
any other structure that will hold even a small amount of water (I even had them on a heating mat in a greenhouse that had very shallow puddles of water!)
You may want to rid yourself of some of these sources of standing water or empty them every three to four days. What if you have bromeliads, a pond or some other standing water and you want to keep them and yet control mosquitoes? There is an environmentally responsible solution. Some bacteria, Bacillus thuringiensis ssp. israelensis or Bacillus sphaericus, only infects mosquitoes and other close relatives like gnats and blackflies and is harmless to all other organisms. Look for products on the market that contain this bacteria.
The hectic pace to contemporary life can justifiably be compared to the seemingly erratic behavior of insect pollinators. Darting from flower to flower with no apparently logical progression for choice of blooms, all the while emitting a mind numbing buzz.
Adult large carpenter bee, Xylocopa sp. Photograph by Paul M. Choate, University of Florida.
This incessant and unending grind of bouncing from task to task has created an atmosphere of tedium and monotony which has become the anthem of many adults. As quick as one chore is complete, another replaces it. Russian composer Nokoli Rimsky-Korsakov wrote what might be considered today’s theme song at the dawn of the 20th century. “Flight of the Bumblebee” catches the frantic haste at which this insect functions, as well as its commonly encountered cousin the carpenter bee.
Bumblebees and carpenter bees are very similar in behavior, coloration and size. The easiest way to differentiate these insects is by their abdomen, the body segment furthest from the head. Bumblebees have an abdomen thickly covered in fine hairs. Carpenter bees lack the fine hairs and have a shiny abdomen.
Xyloxop micans Lepeletier, as the large carpenter bee is known scientifically, is one of more than 500 species worldwide. Almost all members of this genus build their nest by burrowing into dead wood. In the wilds of the panhandle this usually means deadfall timber of almost any sort. Unfortunately, in the areas which include human structures, the nesting sites include wooden timbers and siding.
Unlike European honeybees, the carpenter bees are labeled as solitary bees. There may, however, be several nests in close proximity to these active insects.
Nests are composed of a single parent that lays eggs in a segmented tubular nest. The nest openings are a nearly perfect 5/8 inch (16 mm) hole. Each nest has only a single opening, but multiple tunnels will branch off the main passage. These bees do not eat the wood removed to create the nest channels. Sometimes the holes are not visible to the observer, but the wood emits a buzzing or humming sound when these bees are nesting in hidden locations. In many cases small quantities of saw dust can be found on the ground under the hidden nest.
Heavy or repeated infestations can weaken structural timbers and severely damage siding. Decay and breakage will ultimately follow an untreated incursion.
While the damage caused by carpenter bees can be quite expensive, they may attract an even more destructive predator. Woodpeckers, especially the native pileated woodpecker, dine on carpenter bee larvae at every opportunity. These feathery insect assassins are attracted to the vibrations and hums of the bees hidden in wood. In some cases, the wood acts as a resonator and amplified the insect noise which assures an aerial assault. When discovery of the larvae is confirmed, the woodpeckers attack with a ferocity seldom seen in nature. The rapid-fire staccato of their hammering is loud and devastating.
Structural supports are compromised far beyond the damage done by the carpenter bees, and at a quicker rate. Siding is often shredded and left completely useless.
Commonly available insecticides can help control the carpenter bee population and reduce the prospects of woodpecker damage. Unfortunately, this only adds one more item to the long list of chores and task of contemporary adults.
