Mother Nature has blessed Fort Lauderdale with many assets akin to paradise – from the subtropical climate to the lush green canopies. This is why we love it here so much. Unfortunately, so do some very nasty, uninvited pests, including the Fig whiteflies, mold, and iguanas.
Non-native ficus hedges and trees are under attack by fig whiteflies. First observed in Homestead in 2007, fig whiteflies have since spread through Miami/Dade and north to Broward County, leaving a wide path of defoliation along streets and property lines. A loss of leaves is the most obvious symptom of a whitefly infestation.
Researchers at the University of Florida report that whiteflies are seriously injuring host plants by sucking juices from them, which causes wilting, yellowing, stunting, leaf drop, or even death.
The adult whitefly resembles a very small moth with a yellow body and white wings with a faint grey band in the middle of the wings. Immature states (eggs and nymphs) can be found primarily on the underside of the leaves. The underside of infested leaves look like they are dotted with small, silver or white spots, which are actually the empty “skin” of the pupae after the adult, emerges.
“If your ficus shrubs and trees haven’t gotten fig whitefly yet, it’s only a matter of time before they do,” warns Gene Dempsey, Fort Lauderdale’s Forrester. “By the time you see the first leaf drop, your hedge or tree has probably been infected for about one month.”
The life cycle of the fig whitefly, also called ficus whitefly, is approximately one month. Eggs, which are usually laid on the underside of leaves, hatch into a crawler stage. The crawler wanders around the leaf until they begin to feed. From this point, until they emerge as adults, they are immobile and remain in the same place on the plant.
Although efforts to understand and control this pest are ongoing, there are several potential options. Dempsey, who successfully treated ficus plants in the City’s parks, offers this advice:
- First you have to determine if you already have fig whitefly. If the leaves of your ficus have not started falling off, shake your plant to see if small, gnat-like whiteflies emerge. You can also check the underside of the leaves for whiteflies in immature stages when they appear as small tan to light green discs with red eyes. A magnifying glass is helpful for detection.
- Monitor your ficus plants for early signs of an infestation, because it will be easier to manage the pest before it builds high populations and causes major damage.
- If you detect Fig Whitefly, you may want to consider a two-step treatment. The first step is to spray the hedge to immediately kill the adult whitefly population. Spraying is only effective for 7 to 10 days.
- The next step involves applying a systemic insecticide to the root zone. This can be done by what is called “soil drenches.” Mix the insecticide with water and pour it onto bare soil within the root zone of the plant. It is very important that the drench is applied to bare soil, not mulch or fallen leaves. Most systemic insecticides will offer protection for 6-9 months.
- If your ficus does not show signs of whitefly, you should still apply systemic insecticide.
Dempsey said the chemical Imidacloprid is “ the most popular and seems to have the greatest effect.” It is the active ingredient in Bayer Advanced Tree and Shrub Insect Control, which is readily available at garden centers.
Systemic insecticides recommended include Clothianadin, Thiamethozam, Imidacloprid and Dinetefuran.
Foliar application should be limited and only used for controlling the Whitefly population immediately, while giving time for the systemic chemicals to work.
It is important to note that the most Ficus shrubs and trees becoming infested are not native to South Florida, so don’t blame Mother Nature for this nuisance. Most Ficus plants used for landscaping are native to India, Asia and Africa, which is one of the reasons Dempsey never recommends planting Ficus. “They are not native and they have aggressive roots,” Dempsey said. “Even as a hedge, Ficus roots can cause problems with water and sewer lines.”
Using insecticides to control Fig Whiteflies poses environmental concerns, including the unintended consequence of killing butterfly larvae as well as natural enemies of Fig Whiteflies, like wasps. An environmentally friendly solution to the Fig Whitefly problem is to replace non-native Ficus plants with plants native to South Florida.
This report includes information provided by the University of Florida Tropical Research and Education Center.
Menacing Mold is Lurking
Heavy rains and high humidity make conditions perfect for mold growth. Spores from outside come inside our homes, looking for opportunities to grow. Refrigerator drain pans, soap buildup on shower walls and dusty air conditioner filters are mold hotspots.
By the time mold is visible, it has produced enough spores to contaminate the air in your whole house, creating serious, sometimes deadly health issues.
The first step in avoiding mold is to keep surfaces clean and dry. Fix leaky plumbing and sources of moisture as soon as possible.
A University of Florida report provides detailed information on basic mold prevention:
Mold is a form of fungi and a part of nature. Just as other plants produce seeds to reproduce themselves, mold produces tiny spores to reproduce itself. These spores are floating through outdoor and indoor air and water at almost all times.
Mold spores need three things in order to grow: moisture, nutrients, and warm temperatures. Warm and humid weather provides excellent conditions for mold to grow. This is why we have more mold problems in Florida than in cooler and drier states.
Mold can have harmful effects on human health. We can be exposed to mold either by touching it or by breathing air that contains mold spores. This exposure may cause allergic symptoms and health problems. Reactions differ from person to person, but can include sneezing, coughing, runny nose, sinus problems, nosebleeds, asthma, skin and/or eye irritation, headaches, difficulty concentrating, and even memory loss.
Mold is also destructive to buildings and property. When mold spores grow, they decompose and digest the surface that they are growing on. This results in damage to buildings and discoloration and deterioration of furniture, books, and other items.
As we have explained, for mold to grow, the conditions must be right. First, the mold spores must find their way into the home. Then, in order to grow, the spores need moisture, food, and warm temperatures.
Mold spores are so small that they are invisible to the naked eye. They exist almost everywhere, in indoor and outdoor air. It is not really possible to eliminate mold spores. Instead, we can prevent indoor mold growth by controlling moisture in the air, eliminating nutrient sources, and controlling temperatures.
Control moisture in the air. Moisture control is the key to mold control. Mold spores cannot grow without water. Moisture in our houses comes from many sources. Outdoor moisture can come into our houses either as damp air or as water. It enters through doors, windows, and other openings, such as cracks. We also make moisture inside our house by breathing, cooking, dishwashing, showering, and doing laundry. To prevent mold, dry out any excess moisture and try to prevent moisture from entering the home.
Keep your house clean and eliminate nutrients. Many materials in homes provide a ready source of nutrients for mold. Mold can feed on natural fibers used in clothing and furnishings, paper products, glues, such as those sometimes used in bookbindings, and materials in some grout. Some materials, such as ceramic tile, glossy paint, and glass, do not support mold growth when they are clean. However, the slightest amount of soil on their surfaces will supply the necessary nutrients for mold growth. Soap "scum" left on shower stalls and shower curtains can provide the required nutrients for mold growth. Smoke and cooking oils also can settle on walls and furnishings and provide a soil on which mold will grow. Walls, closets, basements, clothing, and other textiles where mold is likely to grow should be kept clean in order to discourage mold.
Control the temperature in your home. Mold thrives at temperatures between 77°F and 86°F. Hot summer weather encourages mold growth. Air conditioning will reduce the interior temperature of homes, but if the air is humid, the temperature may not be uniformly low enough to stop mold growth. Pay special attention to the areas inside cabinets and closets and behind draperies and furniture. These places are often warmer than the rest of the house. Humidity will be trapped in these areas unless there is a way for air to circulate in and out.
Everyday Mold Prevention Tips
As we have shown, the best way to prevent mold growth in your house is to keep your house clean and dry. Here are some more tips from experts to prevent mold growth:
- Clean your house regularly.
- Remove food stains from furniture as quickly as possible.
- Clean showers and tubs weekly (or more often) so that mildew cannot grow on soap scum and moisture.
- Use fans to circulate the air.
- Keep closet doors open so air will circulate.
- Check the temperature and humidity in your house regularly. Try to keep indoor humidity below 60% relative humidity (ideally, it should be at 30-50%). Use a moisture or humidity meter to measure the relative humidity level. You can buy a small and inexpensive one at your local hardware store.
- Watch for condensation and wet spots. Fix moisture problems as soon as possible.
- Fix leaky plumbing.
- Perform regular heating, ventilation, and air conditioning (HVAC) inspections and maintenance. Keep HVAC drip pans clean, flowing properly, and unobstructed.
- Clean and dry wet or damp spots within 48 hours.
- Don't let foundations stay wet. Provide drainage, and slope the ground away from the foundation.
Credit: Hyun-Jeong Lee and Virginia Peart, University of Florida
Iguanas are not native to South Florida. Lacking a natural predator, the population is soaring. Because they feed on bird eggs and vegetation, iguanas pose a serious environmental threat.
Iguanas also carry salmonella, which doesn’t doesn't sicken them, but can be transmitted to unwary humans.
The iguana invasion is blamed on impulse shoppers who abandon the pets when they get too big.
Concerned residents are asking the State to classify iguanas as “reptiles of concern.” This would require an implanted microchip in the reptile and a $100 licensing fee, making the iguana a less likely purchase by impulsive shoppers who release the pets when they get too big.
If you don’t want to handle a nuisance wildlife problem yourself, you can hire a private trapper to solve the problem. The Yellow Pages list trappers under Animal Removal Services. Call several companies to get the best price quote because prices will vary. The Broward County Animal Care and Regulation Division does not handle nuisance or healthy wildlife calls.
A University of Florida report offers detailed information on Iguanas:
Due to Florida's prominence in the exotic pet trade, iguanas imported as pets have escaped or been released, and are now established in South Florida. This has created unique problems for Florida's homeowners and businesses.
South and Central Florida's subtropical climate allows these large herbivorous (plant-eating) lizards to survive, reproduce, and become part of the Florida environment. Three large members of the iguana family (Iguanidae) have become established in south Florida. These are the common green iguana (Iguana iguana), the Mexican spiny-tailed iguanas (Ctenosaura pectinata) and black spiny-tailed iguana (C. similis).
Large male spiny-tailed iguanas are often misidentified as alligators by startled homeowners because of reduced dorsal spines and dark color. There are many other large lizards established in Florida that some people misidentify as iguanas. The brown basilisk (Basiliscus vittatus) is a large (up to 2 feet) lizard that is often mistaken for an iguana and occurs in the same areas as introduced iguanas. Knight anoles (Anolis equestris) commonly reach between 12-18 inches. Jamaican giant anole (Anolis garmani) males can reach 12 inches. People in South Florida often call these large green anoles "iguanas" or "iguanitos." Occasionally escaped pets that have not established breeding populations are seen by surprised neighbors. These include large lizards like many of the monitor lizards (Varanus sp.).
Damage caused by iguanas includes eating valuable landscape plants, shrubs, and trees, eating orchids and many other flowers, eating dooryard fruit like berries, figs, mangos, tomatoes, bananas, lychees, etc. Iguanas do not eat citrus. Burrows that they dig undermine sidewalks, seawalls, and foundations. Burrows of iguanas next to seawalls allow erosion and eventual collapse of those seawalls. Droppings of iguanas litter areas where they bask. This is unsightly, causes odor complaints, and is a possible source of salmonella bacteria, a common cause of food poisoning. Adult iguanas are large powerful animals that can bite, cause severe scratch wounds with their extremely sharp claws, and deliver a painful slap with their powerful tail. Iguanas normally avoid people but will defend themselves against pets and people that try to catch them or corner them.
Suggested Ways to Deal with Iguanas
Many people enjoy sharing their living space with a few iguanas. Learn to appreciate these exotic creatures. Do not feed iguanas in your yard. This will attract more iguanas and can create problems for both you and your neighbors by creating unnatural concentrations. Do not become a nuisance to your neighbors by feeding iguanas. Pans of cut fruit will attract rats and raccoons as well as iguanas. Be a considerate neighbor and good environmental steward.
Protect valuable plants with cages or screen enclosures. There are currently no repellents registered for preventing feeding damage from iguanas.
Avoid planting species that are preferred food for iguanas.
Remove protective cover such as dense thickets and piles of landscape timbers or rocks. Sheet metal guards of trees, palms, and dock pilings will prevent them from climbing. Fill vacant burrows with concrete and sand during the day when the animals are likely to be away from the burrow. Electric fences on seawalls and docks may deter or stop iguanas from climbing up on to them. Persistent harassment will also encourage iguanas to move to safer pastures.
Raccoons, fish crows, vultures, feral pigs and other predators dig up iguana nests and eat the eggs. Raccoons, snakes, hawks, owls, egrets, herons, cats, and dogs kill the majority of hatchling and juvenile iguanas. After young iguanas reach about two feet in length, they have fewer natural enemies. Automobiles and people are the main cause of mortality of adult iguanas. Alligators may occasionally take adults in the water. In tropical America, large predators like ocelots, pumas, jaguars, anacondas, boa constrictors and people eat adult iguanas. Dogs occasionally catch iguanas in the open and can overtake them before they escape into the water or down their burrows to safety. Freezes keeps iguanas limited to the southern half of peninsular Florida.
Capture and Removal
Iguanas can be captured and removed from private property at any time without special permits. They are considered exotic unprotected wildlife. They may be caught by hand, noose pole, net, or traps. Only live traps and snares are legal in the State of Florida. Check with local authorities for any local ordinances that may limit control options. Babies can be caught by hand or with a thread or monofilament noose on a long bamboo pole. These can be sold or given to pet stores or exotic pet wholesalers.
It is illegal to release iguanas in Florida (39-4.005 Florida Administrative Code). Iguanas are not native to Florida and so are not protected in Florida, except by anticruelty laws. Green iguanas are listed in the Convention on International Trade in Endangered Species II because of their economic importance and over-harvest for the international pet trade in their native range. In Florida, all captured iguanas must be kept in captivity as pets or captive breeding stock, or must be destroyed. Feral adult iguanas rarely make acceptable pets. They never tame sufficiently and are dangerous. Remember, they can deliver severe bites, scratches and blows with their muscular tails.
Trapping, either with live traps and snares, should be considered a last resort. Traditional live animal traps baited with grapes, pieces of ripe melon, papaya, or mango can be very effective, especially if the traps are prebaited for some time prior to setting the trap. Prebaiting simply means securing the door open and placing food in the trap so the animals get used to entering the trap for food. Once they are regularly entering the trap, release the door and set the trap normally. Florida law requires that animal traps be checked at least once every 24 hours. When trapping iguanas, or any animal, check the trap as often as possible. Iguanas will often get cuts and abrasions when trying to escape from traps. Covering the trap with a burlap bag or old blanket when setting it may reduce this behavior by making the animal feel less exposed or vulnerable. There are many other types of live traps that may catch iguanas, such as funnel entrance traps, etc.
Iguanas and many lizards hold their heads up, to better watch for predators, as they walk or run. This behavior makes them ideal candidates for snares. The 24-inch locking snares normally sold for trapping muskrats, mink, or rabbits are large enough for any iguana. Set snares at burrow entrances, holes under fences, along seawalls, or any place that iguanas regularly congregate or move. See Figure 12 on how to set a snare. Snares can kill by strangulation if they are set to do so or the animal struggles too long. Snares are not discriminating and can kill pets or wildlife if they are not carefully set and monitored. Snares set for iguanas should only be set during the day because iguanas are only active during the day, while cats, raccoons, and opossums are generally nocturnal.
During winter cold fronts, cold-stunned iguanas can sometimes be simply picked from branches or picked up off the ground after they fall from the trees. Using boats along canals and in the mangroves when the temperatures are in the 40s°F has been very successful. This is a very effective method to reduce local iguana populations.
Credit: W. H. Kern, Jr., University of Florida