by Matt Lollar | Apr 14, 2016
Scales on a Chinese Elm.
Scales on a Chinese Elm.
Last week as I was basking in the shade of the Chinese Elms (Ulmus parvifolia) in my yard, I noticed some strange lumps on the twigs. Upon further investigation, I realized the “lumps” were scales. Scale insects are serious pests of a number of ornamental plants. Here in Florida there are 13 different families of scales with the most common being armored scales, soft scales, and mealybugs. Scales have piercing-sucking mouthparts which they use to siphon fluids from the leaves, stems, and sometimes roots of many ornamental plants. Heavy infestations cause extensive leaf yellowing, premature leaf drop, branch dieback, and eventually plant death.
Scale Biology
The life cycle of a scale begins with eggs being laid beneath wax coverings or beneath the adult female. Eggs typically hatch in 1 to 3 weeks. The newly hatched nymphs, called crawlers, move around a plant until they find a spot to feed. Once a feeding site is located, their piercing sucking mouthparts are inserted into the plant and the crawlers begin to feed and grow. The males of many scale species develop wings as adults and fly to other plants to reproduce.
The magnolia white scale. Credits: University of Florida
Armored Scales
Armored scales get their armor by secreting a waxy covering over their bodies that is not attached. The scale lives under this covering and uses it as a protection to feed under. Armored scales can be almost any color or shape and range anywhere from 1/16 to 1/8 inch in diameter. For females, these shapes range from circular to oval to long and slender. The males typically have coverings that are more elongate and smaller than the females. As adults, the males are tiny, winged, gnat-like insects and are rarely seen.
Hemispherical scale on coontie. Credits: Lyle Buss, University of Florida
Soft Scales
Similar to armored scales, soft scales secrete a waxy covering, but it is attached to their bodies. Soft scales can be a number of colors, shapes, and sizes and range anywhere from 1/8 to 1/2 inch in diameter. Their shapes vary from spherical to nearly flat.
Mealybugs. Credits: James Castner, University of Florida
Mealybugs
Mealybugs are soft-bodied insects that possess a covering of flocculent, white, waxy filaments. They are about 1/8 inch in length and usually pinkish or yellowish in color. Mealybugs have piercing-sucking mouthparts which they use to siphon fluids from the leaves, stems, and sometimes roots of many ornamental plants. Mealybug damage produces discolored, wilted, and deformed leaves.
Scale and Mealybug Management
- Cultural Control – Plant inspection prior to purchase or installation is the first line of defense against a scale or mealybug population. Make sure to inspect the undersides of leaves and plant stems. Infested sections of plants can be pruned and plant material should be cleaned from the planting area and discarded. Also, you can increase air flow and decrease humidity by proper installation and pruning. Over-fertilizing can also increase pest populations.
Larva of a brown lacewing. Credits: Lyle Buss, University of Florida.
- Biological Control – Predators, such as ladybugs and green lacewings, are usually present in large enough numbers to suppress scales and mealybugs to a desirable threshold. However, broad-spectrum insecticides and bad weather can reduce predator numbers. Look for signs of predation by inspecting dead scales for jagged holes in their waxy coatings. If predation signs are present, use more selective chemical controls and oils as opposed to broad-spectrum products.
- Chemical Control – Timing is everything when it comes to managing scale and mealybug insects. Crawler activity is more pronounced with the flush of new plant growth in the spring. Before application, prune infested plant parts off first to promote greater penetration of insecticides into the foliage. Contact products (acephate, bifenthrin, carbaryl, etc.) must be applied to inhibit the crawler stages of these insects and systemic products (acetamiprid, imidacloprid, thiamethoxam, etc.) can be used on the sessile growth stage. Plants should be sprayed thoroughly to the point of drip or “run off” from leaves, twigs, and stems. Repeated applications may still be necessary even if the timing is right, as crawler populations are often large and crawlers like to hide under old waxy scales. Systemic drenches are also a viable option. With good spray coverage, horticultural oils can kill scales at all stages of growth. Refer to the product label for phytotoxicity and temperature guidelines. Even after successful treatment, the outer coatings of the scales may remain on the plant material for weeks, which can be unsightly. The best way to determine if scales are dead is to squeeze them. They will be dry when squeezed if they are dead and they will ooze liquids if they are living (they were at least alive to the point of being squashed).
For insect identification and additional information on scale control, please see:
A Guide to Scale Insect Identification
UF/IFAS Featured Creatures
Your County Extension Office
by Matthew Orwat | Apr 7, 2016
This spring, most garden plants are putting on lots of tender new growth. The lush foliage is like a free lunch to aphids, whiteflies, mealybugs and thrips. Before broad spectrum insecticides are used to control these pests, consider the impact on beneficial insects. Insecticides that don’t measurably harm predatory beneficial insects include insecticidal soaps and all season horticultural oils, which kill soft-bodied insect pests at application. Here are several common beneficial predatory and parasitic insects that help keep the pests at bay.
Assassin Bug Zelus longipes
Assassin bugs are predators of several leaf feeding and sap sucking insects including the fall army worm and the Asian citrus psyllid. They trap their prey by holding onto it with their forelegs and secreting enzymes into the prey to dissolve the interior tissue. Then they ingest the dissolved tissue.
Lady Bug or Lady Beetle
These insects most commonly feed on aphids, most insect eggs, whiteflies, small caterpillars, scale and mealybugs. They provide a measurable benefit to gardens since they are such generalized feeders. The Lady Beetle larva look substantially different from the adult stage.
Third instar larvae of Hippodamia convergens. Photograph by Luis F. Aristizábal, University of Florida
Newly emerged adult Hippodamia convergens showing typical body markings. Photograph by Luis F. Aristizábal, University of Florida.
Soldier Bug
A different but closely related species of the stink bug, this predator uses its piercing / sucking mouthparts to feed on larval beetles and caterpillars.
Dorsal view of an adult spined soldier bug, Podisus maculiventris (Say), feeding on a mating pair of sumac flea beetles, Blepharida rhois (Forster) (Coleoptera: Chrysomelidae). Photograph by Lyle J. Buss, University of Florida.
Lacewings
The green and brown lacewing is often found around aphid infestations. The larva is the major predator, they make the biggest dent on aphid populations. In addition to aphids, lacewings also feed on scale, mealybugs and several species of insect eggs.
Adult brown lacewing (Neuroptera: Hemerobiidae). Photograph by University of Florida.
Larva of a brown lacewing (Neuroptera: Hemerobiidae) preparing to attack and feed on an aphid. The black-colored aphid to the right was probably parasitized by a wasp. Photograph by Lyle J. Buss, University of Florida.
Predatory Gall Midges
This aphid predator is easily overlooked because it is so small, and resembles the flower fly. They also feed on scale, thrips and mites.
Adult of the predatory gall-midge, Feltiella acarisuga (Vallot). Photograph by David R. Gillespie, Agassiz.
Larva of the predatory gall-midge, Feltiella acarisuga (Vallot). Photograph by Lance S. Osborne, University of Florida.
Flower Flies (Hover Flies)
Flower Flies actually resemble honeybees or bumblebees. People often run from them! The adult is an important pollinator for many crop species and feeds on nectar and aphid honeydew. This time it’s the larva which is predatory and is a voracious feeder of aphids. Large concentrations of larvae substantially reduce aphid populations in aphid infested gardens and fields.
Larva of Allograpta obliqua (Say), a hover fly. Photograph by James F. Price, University of Florida.
An adult male hover fly, Allograpta obliqua (Say). Graphic by Division of Plant Industry.
Parasitic Flies
There are many types of parasitic flies which parasitize a variety of insect pest species. They may inject their eggs into the host, or lay the egg on the surface of their host. Usually they are very small and not noticeable.
Parasitic Wasps
Most parasitic wasp species are tiny, fast and hard to notice. The average gardener is not aware of their rather plentiful existence. They are a common killer of grubs, caterpillars, whiteflies and aphids. They either insert their eggs into the organism or lay eggs on the surface of their host.
A group of adult Cotesia congregata (Say) wasps feeding on honey solution placed on the underside of a tomato leaf. Photograph by Justin Bredlau, Virginia Commonwealth University.
Big Eyed Bugs and Minute Pirate Bugs
While big eyed bugs and minute pirate bugs are not related, they perform similar functions in gardens and agricultural systems by feeding on chinch bug nymphs, psocids, leafhoppers, aphids, thrips, and mites. They are found in variety of ecosystems and do their job anonymously.
Adult bigeyed bug, Geocoris sp., feeding on a whitefly nymph. Photograph by Jack Dykinga, USDA
The minute pirate bugs are black with white markings. They prey on many small insects and eggs, including thrips. About 70 species exist in North America. Photograph by James Castner, University of Florida
References:
by Mary Salinas | Nov 9, 2015
Are you plagued with mosquitoes in your yard? Does it seem like you have a greater infestation than your neighbors? There may be some solutions to solve the problem other than using pesticides that negatively impact beneficial insects in your landscape.
Asian tiger mosquito. Photo credit: Susan Ellis, Bugwood.org.
Mosquitoes are not only annoying, they can transmit serious 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 mosquitos. 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!)
Mosquito larvae. Photo credit: Ari Farajollahi, Bugwood.org.
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.
For more information:
UF/IFAS Mosquito Information Website
Biological Control of Mosquitoes
by Matt Lollar | Sep 23, 2015
Armyworms come in a wide range of colors and sizes. A few of the prominent species living in Florida are beet, southern, and fall armyworms. And the term “living” is not an exaggeration, because Florida is one of the lucky states where it is warm enough for armyworms to overwinter. They are the snowbirds that never leave!
Armyworm damage on a lawn. Credit: Purdue University
Armyworms are notorious for unanticipated invasions. They feed on most turfgrass species and most vegetable crops, but they prefer grassy vegetable crops such as corn. Armyworms feed in large groups and their feeding has been described as “ground moving” in lawns. They feed during cooler times of the day (morning and evening) and they roll up and rest under the vegetative canopy (in the thatch layer in turf and in the base of leaves in vegetables) during the heat of the day.
Armyworms are difficult to control because of their spontaneity. However, in the lawn they hide in the thatch during the heat of the day. Over watering and fertilization can increase the amount of thatch. It is important to follow UF/IFAS guidelines for home lawn management. A good weed control program can also help to deter armyworms, because weeds serve as an alternate food source.
Numerous chemical control options are available, but softer chemicals such as horticultural oils and insecticides containing the bacteria Bacillus thuringiensis are recommended as a first line of defense. Insecticides should be applied in the morning or evening during feeding time. For additional control strategies and basic information please visit the UF/IFAS Armyworm Publication Page.
Armyworm feeding on a young corn plant. Credit: University of Illinois
by Sheila Dunning | Aug 13, 2015
University of Florida researchers maintain a constant vigilance on the potential for mosquito-borne illness concerns. UF/IFAS Florida Medical Entomology Laboratory in Vero Beach tracks rainfall, groundwater levels, mosquito abundance, wild bird populations and virus transmission to animals including horses and sentinel chickens. When mosquito infection rates reach the levels that can infect humans, alerts are sent out. Through the Florida Department of Health, the Centers for Disease Control and Prevention Health Alert Network issues advisories on a weekly basis to those counties at risk. Such an alert was issued for Gadsden, Polk and Walton Counties for the week of July 19-25, 2015. Unfortunately, the first 2015 confirmed human case of West Nile Virus illness in Florida occurred in Walton County shortly thereafter. It was just another reminder for people to take action to reduce their potential for mosquito development in their landscape.
With all the quick afternoon thunderstorms and frequent irrigation events, now is the time to check out where the water is collecting in your yard. The female Culex nigripalpus mosquitoes lay their eggs in temporary flood water pools; even very small ones such as pet watering bowls, bird baths and upturned Magnolia leaves. Dumping out the collection containers every couple of days can greatly reduce the population.
Becoming infected with West Nile Virus is not easy. Mosquitoes usually obtain the virus by feeding on infected wild birds, many of which have migrated from areas that have ongoing West Nile Virus outbreaks. Once the mosquito has drawn infected blood from the bird, the virus goes through a temperature-dependent incubation period within the mosquito. Then, when the infected mosquito “bites” a human or horse the virus mixed in saliva is released into the blood stream of the second host. West Nile Virus is not transmitted from one human to another. Nor is it transmitted from bird to human or from horse to human.
Thanks to a devoted set of researchers and government public health officials, here in Florida we are able to monitor mosquito-borne illnesses quickly and effectively. Additional partners, such as local veterinaries, sentinel bird stations and the Florida Fish and Wildlife Conservation Commission (FWC) serve as reporters for virus population. Should an individual come across dead birds without an obvious cause, reporting them to the FWC at www.myfwc.com/bird/ is the best thing to do.
As for protecting yourself, here are a few pointers:
Stay indoors at dusk (peak mosquito biting time).
If you must be outside, wear long sleeves and pants and/or mosquito repellents containing the active ingredient DEET.
Repair torn door and window screens.
Remove unnecessary outside water sources.
Flush out water collected in outdoor containers every 3-4 days.
Disturb or remove leaf litter, including roof gutters and covers on outdoor equipment.
For additional information, contact your local Extension office about obtaining a free Florida Resident’s Guide to Mosquito Control.
by Sheila Dunning | Jul 7, 2015
There are more than 100 species of plants and animals living in Florida that are in danger of extinction. These trees, flowers, reptiles, amphibians, birds, fish, mammals and invertebrates are listed as either threatened, endangered or species of special concern. As stewards of the land we must question, “What could the loss of a torreya tree, a lupine, a salamander, a butterfly, a woodstork, a right whale, a manatee, a sea turtle or a black bear do to our environment and our quality of life?”
Biological diversity is the variety and variability of species present in an ecosystem including the complex interactions of the many species. Regardless of their size or apparent significance, each species has a role in the circle of life and the food web. Preservation of all species is important. No one knows which ones hold the answers to the future of human existence on this planet.
Many significant developments in medicine have come from obscure plant and animal species. Modern day research includes a vaccine against leprosy being developed because of the nine-banded armadillo and horseshoe crabs being used in developing laboratory tests and finding remedies for several bacterial diseases. In agriculture, genes from wild species may provide the resistance for plant diseases, insects or even weather extremes that could save us from crop failure or possible starvation. There is an interdependence among living things. The extinction of one species may have a domino-like effect on other species. Stability of an ecosystem depends on bio-diversity.
To protect our future and the future of wildlife, the Endangered Species Act became federal law in 1976. This act is intended to protect and promote recovery of plants and animals that are in danger of becoming extinct as a result of human activity. The Environmental Protection Agency is responsible for ensuring the endangered species are protected from pesticides.
Pesticides can kill endangered plants and animals directly or indirectly. Birds mistaking them for food may eat granules, baits or treated seeds. Water contaminated with pesticides ranging in concentrations of less than 0.1 to 1.0 parts per million (ppm) can kill fish. Animals that eat treated crops, drink or wade in contaminated water or feed on tainted prey can be killed indirectly. Some pesticides can build up to lethal levels as predators consume multiple poisoned prey species.
There are certain things you can do to lessen the harmful effects of pesticides on fish and wildlife. Read all pesticide labels carefully to find out whether the use of the product requires special steps to protect endangered species. Determine if the site is designated as the current habitat of an endangered species. Find out this information by visiting http://www.epa.gov/espp/ and http://myfwc.com. When you have a choice of pesticides to use, choose one that is less or non-toxic to fish and wildlife. Read and follow the “Environmental Hazards” section and use the special precautions and measures to minimize harmful effects. Treat only the areas that need to be treated. Leave a buffer zone (untreated area) between bodies of water and treated areas. It is your legal and moral responsibility to protect endangered species by careful use of pesticides in and around their key habitat areas.
Information for this article was derived from University of Florida publications “Pesticide Effects on Nontarget Organisms” by Frederick Fishel and “Applying Pesticides Correctly” by Thomas Dean and Norman Nesheim.
