by Sheila Dunning | Aug 19, 2016
With all the media discussion of “bad” insects, like mosquitoes, many of the good guys are forgotten. One that has been very active this summer is the blue mud dauber, Chalybion californicum. These wasps are metallic blue, blue-green or blackish in color with very short narrow waists. During the summer, female blue mud daubers build nests by bringing water to abandoned mud nests made by other species of mud dauber wasps. They form new mud chambers, stock them with paralyzed spiders and a single egg, then seal the chambers with more mud. Their offspring stay in the chamber, feeding on the spiders, and then pupate in a thin silk cocoon. They spend the winter in the nest, emerging the following spring as adults.
Blue mud daubers are solitary wasps and not known to be aggressive. When the females have carried water to an old black and yellow mud dauber’s nest, she softens it and remolds it to her needs. The result is a very lumpy version of the originally smooth nest. Next she must fill the nest with food for her future offspring. The blue mud dauber prays on spiders.
If orb weavers, lynx or crab spiders are plentiful, the blue mud dauber is able to land on their web without getting entangled and pluck the web to simulate an insect in distress. When the spider rushes to capture its prey, the poor arachnid becomes the victim of the wasp’s paralyzing sting and is quickly flown to the mud nest. However, the preferred host of the blue mud dauber is the southern black widow. Even without the elaborate web game, this wasp can control a dangerous nuisance. Once at the nest with her spider victim, the blue mud dauber stores the paralyzed arachnid at the bottom of a mud cell and lays a single egg onto its body. When the wasp larva hatches it consumes the remaining body of the spider. With a full belly, the mature larva spins a papery silken cocoon within the mud nest and begins to pupate. The following spring an adult wasp chews a round hole in the end of the mud cell and exits it’s winter home.
As adults, the blue mud dauber feeds on nectar from flowers and honeydew secreted by insects. Should you encounter a large congregation of this normally solitary wasp, don’t be alarmed. It is probably just a bunch of male blue mud daubers gathering together to sleep it off, after a heavy day of “drinking.”
So, rather than having to cover yourself in DEET just to spend the evening on the patio, brave the heat (with water bottle in hand, of course) and spend the daytime hours watching the blue mud daubers prepare their nest for next year’s young. Maybe the media will pick up on wasp that are reducing black widow populations, rather than the dangers of mosquitoes.
by Molly Jameson | Aug 12, 2016
Ants can be treated with spinosad in vegetable gardens. Photo by Molly Jameson.
There’s nothing worse than sinking your fingers into your garden soil to dig up a potato, plant a seedling, or pull up a radish, and be met with a sharp, painful sting, and little red critters rocketing up your arms. If you are a gardener in the panhandle, my bet is that you know exactly to what I refer: fire ants!
Fire ants are certainly not native to our area. These guys are an invasive species from South America that are very resilient, and many are territorial, with the potential to drive out any native ant populations. Fire ants arrived in the 1930s, and can now be found throughout most of the southeastern United States.
So when you end up with fire ant mounds engulfing your carrot patch, what can be done? Since fire ants in your garden mean fire ants in your food, the least toxic control methods are of high importance and conventional broadcast bait treatments and mound treatments should be avoided. Even in your lawn, be careful when using strong insecticidal bait treatments, as these can harm the native ant populations that help control the spread of fire ants. This can then lead to a strong resurgence of fire ant populations that can outcompete the native ants.
Although completely controlling fire ants in an area is not possible, there are sustainable management techniques that can help. Some fire ant colonies have a single queen while others have multiple queens. Either way, in order to eliminate a fire ant colony, all queens in the colony must be killed. Fire ants are omnivorous, in that they eat plants, insects, sugars, and oils. The catch is that they are only able to ingest liquids, so solid food must be brought into the colony, where larvae regurgitate digestive enzymes onto the food, breaking it down into liquids. Therefore, any method of control by ingestion will need to be in liquid form, or the ants must be able to bring the material into the colony, without first being exterminated.
Fire ants can become a problem around and in raised vegetable gardens. Photo by Molly Jameson.
There are some commercially available products that contain boric acid or diatomaceous earth. These products may reduce populations, but eliminating whole colonies with these products can be a challenge.
The use of a nervous system toxin called spinosad is effective on fire ant populations and is considered safe to use in vegetable gardens. This toxin comes from a bacterial fermentation process, and is therefore considered organic. But be aware, even though there are organic products with ingredients derived from botanical sources such as rotenone and nicotine sulfate, they should not be used in vegetable gardens. When using chemical methods of control, always follow the directions on the label carefully.
One physical method of control is the use of hot water. Three gallons of scalding water, which is between 190 to 212ºF, has been used on colonies with a success rate of 20 to 60 percent, when applied in several treatments. You will want to slowly pour the water on the colony, being extra careful not to get burned, and avoid injuring any surrounding plants. If you are like I am, and you often leave your garden hose in the hot sun, you can spray the ant colonies with the hot water, as you wait for the water to cool off enough to water the garden. Hot water control takes persistence, but you can eventually drive the ants out.
Another method of physical control is excavation. This requires digging up the mound, putting it in a bucket, and taking it to another location. Apply talcum or baby powder to your shovel handle and bucket to help prevent the ants from escaping and crawling up to sting you.
One reason fire ants are so rampant in the United States is that they have little competition or natural enemies. Scientists have released multiple species of phorid flies, natural parasites of fire ants in South America, and a few species have become established. Scientists at UF/IFAS are currently researching additional fire ant biological control methods, such as the use of a fungi, which has shown promise.
Remember, not all ants in the garden are bad guys! Many species act as roto-tillers, aerating and redistributing nutrients in the soil. They also play a role as decomposers as they assist in turning dead insects into soil nutrients. Ants can disturb garden pests by attacking them or interrupting their feeding, mating, and egg laying processes. Additionally, ants are a food source for wildlife, such as other insects, frogs, lizards, birds, spiders, and even some mammals.
by Mary Salinas | Jul 7, 2016
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
The Florida Department of Health has recommendations for preventative action to take when traveling to any location that has confirmed Zika virus.
- 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.
For more information:
Zika, a Mosquito-Transmitted Virus
Mosquito Repellents
UF/IFAS Mosquito Information Website
Florida Container Mosquitoes
by Mary Salinas | Jul 7, 2016
Peppers and tomatoes are in the same plant family – solanaceae or more commonly known as the nightshade family – and can be susceptible to some of the same diseases. This is true of Tomato Spotted Wilt Virus (TSWV). The solanaceae family includes potatoes, eggplant, tobacco, petunia, tomatillo and deadly nightshade in addition to pepper and tomato.
Pepper with TSWV. Photo credit: Mary Derrick, UF IFAS Extension.
This virus is spread by very small insects known as thrips. They acquire the virus as larvae when feeding on an infected plant and then transmit the disease when they fly to other susceptible plants as adults.
Initial symptoms are yellowing and distortion of the leaves. The leaves can also display yellow or brown circular ring spots. The severity of the virus can depend on the particular cultivar of pepper, its age and the environmental conditions in which the pepper is growing. Fruit can develop yellow, brown or ring spots as well.
TSWV infection showing ring spot on leaves and lesions on fruit. Photo credit: Mary Derrick, UF IFAS Extension.
If you think your pepper has TSWV, consult your local extension agent to confirm the diagnosis. But once infected, there is no treatment for the plants and they should be pulled up and disposed of in the trash to prevent other susceptible plants from becoming infected.
For more information:
Some Common Diseases of Pepper in Florida
by Blake Thaxton | May 17, 2016
In the last few weeks, more garden pests have arrived! It is a fact of life in northwest Florida that we will have a few things in our garden including heat, moisture (humidity and rainfall), and BUGS! With a cooler spring the arrival of some of the troublesome pests in the garden seemed to be delayed a few weeks. It was nice while it lasted but the insect pests are here to stay until frost in the fall or winter (at least we hope for a frost this year).
There are thousands of insects that you can see in your garden. It’s wise to identify them before making a decision to spray an insecticide or remove them by another method. Insect samples can be taken to your local county extension office for identification.
In this article we will just discuss one of the top insect pests in the vegetable garden, caterpillars, and what you can do about them.
Mature larva of the cabbage looper. Photograph by John L. Capinera, University of Florida.
Beet armyworms, fall armyworms, hornworms, cabbage loopers, southern armyworms, tomato fruitworms, and other caterpillars love to feed on tomato foliage and fruit. They will show up eventually on tomato plants in the garden, if not this year then in the future. These larvae are immature moths and cause a lot of damage if left unchecked. The homeowner can control them effectively with Organic Materials Review Institute (OMRI) approved pesticides. A bacterial biological insecticide called Bacillus thuringiensis, also referred to as B.t., can be very effective in controlling these caterpillar pests. B.t. is a stomach toxin to these pests and will cause them to quit eating and starve to death. The key to using B.t. effectively is to routinely apply it before the caterpillars hatch from their eggs as the smaller caterpillars are easiest to control. Larger caterpillars are more difficult to control.
For more information related to using OMRI pesticides:
Organic Vegetable Gardening in Florida
Insecticides for Organic Commercial & Backyard Vegetable Production
by Matthew Orwat | May 12, 2016
Burweed, Soliva Sessilis. – Image Credit: Joseph M. DiTomaso, University of California – Davis, Bugwood.org. Creative Commons License
This spring, lawn burweed has been an especially noticeable problem in lawns. Extension offices throughout Northwest Florida have been fielding many questions and finding solutions to lawn burweed infestations!
On the top of my list of lawn related annoyances is stepping into a patch of burweed, Soliva sessilis, which is in the sunflower family and is also known as spurweed. The leaves are opposite along the stem and sometimes resemble parsley. The main ways in which burweed can irk the casual gardener are sticking to socks, sneaking in with the dog, or littering flower beds with its nuisance. It can also hide in the house and reappear when shoes are removed. This causes pain in both the foot and the ear.
Aside from herbicides, maintaining a healthy vigorous lawn will prevent weeds from taking over. If your lawn is reasonably healthy and only a few instances of this weed exist, try to mechanically remove them and encourage the lawn to outgrow them.
If cultural methods aren’t sufficient, science has given us several options to control this irksome pest. Herbicides containing the active ingredients dicamba, 2,4-D or atrazine are good at controlling burweed as a post emergence control when applied from December through March. Be careful to use reduced rates on centipede and St. Augustine lawns, and never use more than the labeled rate since injury can occur when using these products on these species. Later applications have less effect on burweed because as it matures it is harder to control. Additionally the burs, once present on the lawn, are hard to remove. As the daytime temperatures rise to 90ºF, some of these herbicides may cause lawn damage. Try to keep the spray residue outside of the root zone of desirable plants to avoid injury and always follow label directions.
Be aware that burweed reproduces by seed, so mowing it down will only increase the problem by burying the seed for fall germination. Although we are now in the month of May, control of actively growing burweed might still be warranted if it is still flowering and setting seed. As temperatures warm up burweed will die, as it is a winter annual. In cases where it is already dying, control is not warranted since the natural cycle of winter annuals is concluding.
If an infestation of burweed has occurred this year, take note. The best time to apply pre-emergent herbicides to control burweed is in October. A widely used preemergence product for burweed control is isoxaben, which is sold under the brand name of Gallery as well as others. It prevents the weed from emerging from the ground when it germinates and can be used on St. Augustine, centipede, bahia and zoysia lawns, as well as in ornamental shrub beds. In northwest Florida, this herbicide needs to be applied in October for best results. A second application later in the season might be warranted. For more information about control, please consult this excellent article on lawn burweed management.
The active ingredients mentioned above are present in a variety of ‘trade name’ products* available from your local garden center, farm supply or co-op. Be sure to read label instructions carefully and contact your local extension office for any assistance. I hope all the northwest Florida lawn managers prevent burweed during the upcoming fall so that lawns will be burweed free next spring.
Happy Gardening!
If orb weavers, lynx or crab spiders are plentiful, the blue mud dauber is able to land on their web without getting entangled and pluck the web to simulate an insect in distress. When the spider rushes to capture its prey, the poor arachnid becomes the victim of the wasp’s paralyzing sting and is quickly flown to the mud nest. However, the preferred host of the blue mud dauber is the southern black widow. Even without the elaborate web game, this wasp can control a dangerous nuisance. Once at the nest with her spider victim, the blue mud dauber stores the paralyzed arachnid at the bottom of a mud cell and lays a single egg onto its body. When the wasp larva hatches it consumes the remaining body of the spider. With a full belly, the mature larva spins a papery silken cocoon within the mud nest and begins to pupate. The following spring an adult wasp chews a round hole in the end of the mud cell and exits it’s winter home.
