Distorted Leaves Caused by Mites

One of my favorite native plants is winged sumac.  I like this plant not only for its ornamental beauty, but also for its fruit that can be dried and used as seasoning and to make tea.  So you can understand my concern when one of my prized winged sumac plants had distorted leaves.

Eriophyid mite damage on winged sumac

Eriophyid mite damage on winged sumac. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

After doing a little research and speaking with one of our UF/IFAS Specialists, I was able to determine that the leaf distortion was caused by eriophyid mites.  Mites are not insects and are more closely related to spiders.  They normally have four pairs of legs, however eriophyid mites only have two pairs of legs.  They are microscopic, elongate, spindle-shaped, and translucent.

Eriophyid Mite

An eriophyid mite. Photo Credit: USDA, Agricultural Research Service.

Eriophyid mites cause galls (sometimes called witch’s broom) on various species of ornamental shrubs.  Symptoms include early and late bud distortion, distorted leaves, and possibly plant death.  In fact, the species Phyllocoptes fructiphilus is the vector for the viral disease of roses called Rose Rosette Disease.  Sometimes the damage can be confused with herbicide damage.

Control options are currently being evaluated for eriophyid mites in the home landscape.  Removing distorted plant material and removing it from the site can help prevent the spread of mites.  If you suspect eriophyid mites are the cause of your distorted plants then samples should be collected.  To collect samples: 1) Prune off symptomatic plant material and immediately place into a vial with rubbing alcohol; 2) label with collection date, plant species, and location; 3) mail to the Landscape Entomology Lab in Gainesville at P.O. Box 110620, Gainesville, FL 32611.

For more information on eriophyid mites and the sampling process, please see the fact sheet “Unusual Galls on Woody Ornamentals” from Erin Harlow and Dr. Adam Dale.

For more information on other mites that could be infesting your landscape, please go to this link from the Mid-Florida Research and Education Center in Apopka, FL.

Mosquito Control in Your Landscape

 

A natural disaster such as Hurricane Michael can cause excess standing water which leads nuisance mosquito populations to greatly increase. Floodwater mosquitoes lay their eggs in the moist soil. Amazingly, the eggs survive even when the soil dries out. When the eggs in soil once again have consistent moisture, they hatch! One female mosquito may lay up to 200 eggs per batch . Standing water should be reduced as mush as possible to prevent mosquitoes from developing.

You should protect yourself by using an insect repellant (following all label instructions) with any of these active ingredients or using one of the other strategies:

  • DEET
  • Picaridin
  • Oil of lemon eucalyptus
  • Para-menthane diol
  • IR3535
  • An alternative is to wear long-sleeved shirts and pants – although that’s tough in our hot weather
  • 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.

Now let’s talk about mosquito control in your own landscape.

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.

 

For more information:

Mosquito Repellents

UF/IFAS Mosquito Information Website

 

Beneficial Wasp is Effective Control for Tomato Hornworm

Beneficial Wasp is Effective Control for Tomato Hornworm

This tomato hornworm is being parasitized by beneficial wasps. Photo credit: Henry Crenshaw

Why would anyone allow dozens of wasps to thrive in their garden? Why would they let caterpillars keep moving through their pepper bushes? Don’t they know you can spray for that?

As Extension agents, one of the tenets we “preach” in gardening is the concept of Integrated Pest Management (IPM). This technique involves a series of insect control measures that begin with the “least toxic” method of control, using chemicals as a last resort. One of those least toxic measures is “biological control”, in which a natural predator or parasite is recognized and allowed to remove a pest insect naturally. It is important to be able to recognize some of the more common garden predators and parasites. Many times these insects look strange or dangerous, and they are mistaken for pests and killed.

One such beneficial insect to the home gardener is the braconid wasp (Cotesia congregatus). Most people shudder at the mention of wasps, but these tiny (1/8 inch long), mostly transparent wasps are of no danger to humans. Quite the opposite–they are an excellent addition to gardens, especially if you are growing tomatoes or peppers. One of the major pests to these favorite vegetables is the tomato hornworm (Manduca quinquemaculata), a fat green and white-striped caterpillar.

The beneficial wasp can control hornworms because females lay eggs under the caterpillar’s skin, after which the eggs hatch and larvae feed on the hornworm. After eating through the caterpillar, they form dozens of tiny white cocoons on the caterpillar’s skin. The tomato hornworm is rendered weak and near death, and the vegetable crop is saved.

If you happen to find a tomato hornworm covered in these small oval cocoons, consider yourself lucky. Let the process continue, allowing the new generation of beneficial wasps to hatch and continue their life cycle. They will control any future hornworms in your garden, and the whole process is fascinating to watch!

For questions on integrated pest management, beneficial insects, or growing peppers and tomatoes, call your local County Extension office.

 

 

 

Feeding Caterpillars Aren’t Always Cute

Feeding Caterpillars Aren’t Always Cute

Looks, as the old saying goes, can be deceiving. It is a cautionary pronouncement from experience, usually painful and expensive, to serve as a warning to those who follow and hopefully avoid similar complications if they listen.

In most situations a threat in nature can be easily identified and avoided with a little effort. Except for those situations where the careless or clueless individual blunders into problems, a little observation and logic dictates the potential outcome from a close encounter.

Yellow jackets have stingers, so they must stink something. Alligators would not have all those large and pointed teeth unless they needed to bite something.

Those assumptions are easily deduced by anyone who uses even the slightest quantity of judgement and forethought. Unfortunately, there are occasions where the potential agony is disguised by bright colors and a benevolent appearance.

Such is the case with the caterpillar of the Io moth. Automeris io, this insects entomological name, is a large native moth.

This insects’ range extends from south central and maritime Canada to the eastern half of the U.S. It is found in every Florida County, even into the Keys.

The wingspan of this moth can reach an impressive three and a half inches. Males of this species tend to have a slightly brighter appearance than the females.

Both sexes have large eye spot on each hindwing as a defense device. When revealed, the spots appear as the eyes of predatory creature meant to bluff other aggressors into retreating.

Adults of this species live only a week or two, so reproduction is a priority activity.  Luckily, at least for the parents, there are plenty of host plants in north Florida.

Oaks, sweetgums, redbuds, and ash are among the choice meal sites for the developing caterpillars. The eggs are commonly laid in clusters of 20 or more and the caterpillars go through five development stages before reaching adulthood.

Unlike the parents which are active almost exclusively at night, the larvae spend their days hidden in the tree leaves they are consuming. These caterpillars are quite animated and active, frequently seen moving inline from one feeding site to another.

Initially orange, they change to a lime green as they mature. They also develop clusters of spine strategically place across their plump bodies.

Photo Caption: The colorful Io moth caterpillar is covered by fragile spines. Each contains a painful venom for anyone who physically contact this insect larvae.

Distinct from their parents’ eyespot bluff, the spines are a serious defense designed to assure the caterpillars reach maturity unmolested by birds or other predators which would otherwise find them a suitable snack option.

Unlike a pit viper which injects venom via a syringe-like fang or a stingray which retains its barb in a venom saturated sheath, this caterpillar’s spines work differently. Each spine contains a sac filled with the defensive solution.

When contact is made with the hollow spines, deliberately or accidentally, the fragile structure breaks and releases the toxin.  The pain is almost instantaneous, intense, and can be a serious health treat for those who have an allergic reaction.

Not usually seen on the ground this caterpillar can be encountered on lower limbs, to the detriment of the unlucky individual. The colorful, toy-like appearance hides a very different reality.

To learn more about north Florida’s stinging caterpillars, contact the local UF/IFAS County Extension Office. Click here for contact information.

 

 

Growing Squash in the Home Garden

Are you interested in growing squash in your garden?  Do you know the difference between summer squash and winter squash?  Check out this very informative instructional video on growing squash in your home garden by Walton County Agriculture Agent Evan Anderson.

 

 

Late Spring Signals Leaf Gall for Some Camellias

Camellias are a Panhandle favorite, as the flowers can highlight a landscape with bright, vibrant colors in fall and winter. However, spring time can bring about these colors in a negative way, in the form of leaf gall.

The camellia is native to Asia and brought to America in the late 1700’s. These plants have proven to be a dependable addition to the southern landscape with minimal care. When camellias are correctly planted and cared for, minimal disease problems arise. However, camellias can contract leaf spot, dieback, root rot and bud and leaf gall.

Camellia Gall Credit: Patty Dunlap, Gulf County Master Gardener.

 

Leaf and bud galls are caused by the fungus Exobasidium vaccinia. The gall appears as thickened, waxy and enlarged leaves or buds during the cool spring months. One or several leaves on a single shoot may be affected. Once you’ve found infected leaves, no chemical control will be effective. Actually, no fungicide has been found very effective in combatting this condition. However, control can be accomplished in the home garden by simply pinching off and destroying infected leaves. Disease activity usually stops with warmer weather. A best management practice to curb infection is to reduce overhead watering during cool, wet weather periods of spring. Great news, this condition does not cause any long-term issues with the plant.

For more information regarding fungal issues in landscape plants, contact your local county extension office.

Fun camellia fact: The young leaves of the species, Camellia sinensis, are processed for tea, one of the world’s most popular drinks. Please see UF/IFAS EDIS publication, “Tea Growing in the Florida Landscape” by Jonathan H. Crane and Carlos F. Balerdi: http://edis.ifas.ufl.edu/pdffiles/HS/HS30800.pdf

Supporting information for this article can be found in the UF/IFAS EDIS publication, “Camellias at a Glance” by Sydney Park Brown: http://edis.ifas.ufl.edu/pdffiles/EP/EP00200.pdf

UF/IFAS Extension is an Equal Opportunity Institution.