Bites and Stings

By Ann Barnes, EMGV

The past week has been a tough one for this gardener. First, I disturbed a hidden fire ant mound and received multiple stings on both ankles. Two days later, while weeding near my mailbox I came too close to a new wasp nest and was stung through my garden glove. Fortunately, I have a well-stocked first aid kit handy and was able to treat the stings and return to the garden. Are you prepared for bites and stings that may happen when you’re outside?

Mosquitoes, ticks and chiggers bite in order to feed. While their bites can cause itching and may carry disease causing organisms, these insects are not venomous. To avoid bites from these insects, use repellent and wear clothing that covers the skin. Remove ticks promptly. Itchy bites can be treated with an anti-itch cream. Seek medical attention if you have symptoms of a mosquito or tick borne illness (such as headaches, fever, nausea, and muscle aches).

Bees, wasps, and fire ants sting as a defense, injecting venom with each sting. While bees can only sting once, wasps, yellow jacket, hornets, and fire ants are capable of multiple stings. Stingers are modified egg-laying structures, so only females are capable of stinging.

Fire ants swarm when their mound is disturbed. Many ants may climb onto a person, attach to the skin with their mandibles, and will begin stinging within 10 seconds. Fire ant venom causes a burning sensation. After several hours, white pustules develop at the site of the stings. If you are stung, quickly move away from the area and brush all ants from your body. Carefully wash the area and apply cold compresses. To reduce the chance of infection, avoid breaking the pustules open. Pain can be treated with over the counter analgesics, and itching with an anti itch cream.

The best defense for fire ant stings is avoidance. Wear protective clothing and avoid visible mounds. Be alert for foraging ants when weeding gardens or walking in tall grass.

Bees, wasps, and other related insects are not deterred by insect repellents, so avoidance is the best protection from stings. Protective, light colored clothing is also recommended. Avoid wearing perfumes or using highly scented soaps when working outside. Do not swat at bees or wasps. Picnic areas and garbage cans can attract some kinds of stinging insects, while others are fond of flowering plants. Be cautious and observant when near areas that wasps and bees may find attractive. Wasps, in particular, can be aggressive in guarding their nests, particularly in late summer and fall.

Bee and wasp stings can be very painful. Other symptoms include redness, swelling, and itching. If you are stung, try to remove the stinger by scraping, NOT squeezing, the area. Squeezing or using tweezers could cause more venom to be released. Ice the area or use cold compresses to reduce swelling. A topical analgesic or anti itch cream can be used if necessary. Oral analgesics or antihistamines can be taken if necessary.

Be prepared, be observant, but don’t let the fear of insect bites keep you from enjoying the outdoors!

Warning: if you or another person is stung by an insect and has any of the following symptoms:
difficulty breathing (wheezing or shortness of breath)
difficulty swallowing
nausea
weakness
dizziness
hives
confusion
loss of consciousness
SEEK MEDICAL ATTENTION IMMEDIATELY!

Sources:

The Buzz About Insect Bites and Stings

Using Insect and Tick Repellents Safely

Fire Ant Stings

Bees and Wasps

Non-Honey Bee Stinging Insects in North Carolina

Other things that might bite if you encounter them in your yard:

Spiders

Snakes

Caterpillars and Wheel Bugs

Dragonflies and Daydreams

by Andrea Laine

This summer my Durham garden has been graced by two large blue dragonflies with wingspans of almost three inches.  I do not recall ever noticing a lingering presence of dragonflies anywhere else I have gardened. So I was struck with delight when one day’s sighting led to another and another and another.

I’ve enjoyed watching them for weeks now.  From my second-story home-office window I see them zoom around in circles and spirals like vintage planes at an air show.  They are fast and yet delicate. Sometimes they fly in unison, which is especially eye-catching when rays of sun make their lacy wings seem to sparkle. Other times they fly solo, zig-zagging from one garden spot to another, from one perch to another. Pointy objects seem to be their favorite perches: the tip of the orange beak of a larger-than-life blue heron sculpture that marks the entry to my front walkway; or atop the silver metal antenna of the 1990 Toyota parked in the driveway.

Today as I paused waiting for my watering can to fill, one swooped over and hovered before me at (my) eye level as if to say hello. Or at least, let us formally acknowledge one another’s existence. No longer could I just be mesmerized by their daily dance; My curiosity was piqued. I had to learn more about this unique and colorful creature.

Dragonflies belong to the scientific order Odonata, meaning “toothed ones,” and the suborder Anisoptera, meaning “different wings.”  Their hindwings are distinctly larger and differently shaped than their forewings. There are hundreds of dragonfly varieties in the United States.  The anatomy of wings and their venation can be very complicated. Most dragonflies can be identified to the level of genus and many to the level of species by just knowing the wing venation.

I have sunny, hot days to thank for a dragonfly’s presence.  Many dragonflies maintain an internal temperature as high as 110 degrees F. This is accomplished by the burning of calories during physical exertion and by staying in the sun. A cold dragonfly preparing to get the day started will shiver its wings to create heat in its thorax until it has warmed itself enough to take flight. On cool or cloudy days, dragonflies will disappear to protected perches.

Dragonflies live to eat and mate. They are formidable and efficient hunters aided by excellent eyesight, resilient and maneuverable wings, spiky legs that can snag live prey, and a powerful thorax serving both the wings and the legs.  Their prey includes mosquitoes, moths, beetles, butterflies and damselflies.

Dragonflies have no sense of hearing, cannot smell and are unable to vocalize. Their antennae are tactile sensors, picking up even slight movement. Antennae also help dragonflies measure wind direction and wind speed.  They can fly up to 35 mph and they mate while flying in the air.

To drink, a dragonfly will thrust its body onto the water’s surface and absorb water through its exoskeleton. I haven’t witnessed my visitors doing this, but perhaps they are making use of a couple of 12-inch saucers I leave in the garden to collect with rainwater for thirsty beneficial insects like bees.

Dragonflies undergo three stages of development: the egg, the larva (nymph) and the adult.

The eggs are laid underwater in plants in ponds or marshy areas. When a nymph is ready to mature to the adult stage, which could be one to three years after hatching, it sheds its larval skin and crawls up a plant stem, a rock, a tree trunk or a dock to exit the water.

The adult dragonfly tends to emerge from the water very early in the morning to protect itself from predators, particularly birds. The mortality rate at this juncture can be very high.  And, as adults they live just a couple of months.  Knowing that makes me appreciate even more that this particular pair of dragonflies chose to live in my garden this summer.

Sources:

More about the biology and behavior of the dragonfly:  http://mndragonfly.org/defined.html.

Also, http://agrilife.org/dragonfly/

Photos of dragonflies: http://www.carolinanature.com/odonata/  (a link recommended by ces.ncsu.edu)

The Book of Dragonflies of the East, a fully illustrated guide to all 336 dragonfly and damselfly species of eastern North America  http://press.princeton.edu/titles/9538.html

 

Insect Pests We’re Noticing Now – Cankerworms

If you’ve been outside in the past week or so, you’ve probably noticed little green inchworms. While my 9 year old daughter thinks they’re adorable, they are actually pests called cankerworms. Two species, spring and fall cankerworms, hatch in early spring. The larvae (those inchworms we’re seeing) feed on young leaves before dropping to the ground on a silk thread. The larvae then pupate in leaf litter through the summer. When the adults emerge, the females climb trees and deposit eggs on twigs. Fall cankerworm adults climb in October – November, while spring cankerworm adults emerge in early spring.

While these cankerworms will generally not kill a tree, they can defoliate enough branches to cause the tree to be unsightly, and could potentially weaken trees.

While control of these pests would be difficult and costly at this time of year, banding your trees and applying a sticky substance called Tanglefoot (TM) in the fall can trap the adult females and prevent them from laying eggs. This video from NCSU shows how to apply the bands to a tree. Workshops have been held in Durham during previous fall months, and will be publicized here when scheduled in the coming autumn.

Scouting for Insect Pests, June Edition

Squash Bugs

squashbugweb

Photo: growingsmallfarms.ces.ncsu.edu

Squash bugs, which have overwintered as adults, are actively laying eggs now. Egg clusters can be found on the undersides of leaves. Remove and crush the eggs to reduce the population of squash bugs.

squash_bug_eggs
photo: Whitney Cranshaw, Colorado State University, http://www.insectimages.org

Nymphs and adult squash bugs suck sap from plants and can quickly destroy squash vines. Adults and nymphs frequently hide under damaged leaves and at the base of plants. Keeping debris and mulch away from the base of plants reduces cover for the bugs and may also reduce damage. In fact, Clemson University suggests the following method of trapping adults and nymphs: “The secretive nature of squash bugs can be used to your advantage in controlling these pests. Place a small, square piece of old shingle or heavy cardboard under each squash plant. As bugs congregate under it for protection, simply lift the trap and smash them with your hoe (or shoe).”

http://www.clemson.edu/extension/hgic/pests/plant_pests/veg_fruit/hgic2207.html
http://www.ext.colostate.edu/pubs/insect/05609.html

Mealybugs

mealybug

Photo: ucanr.edu

These pests can be a problem on ornamental plants in the landscape as well as on houseplants. Female mealybugs are oval shaped, soft-bodied, wingless, and covered with a fluffy wax. Males are gnat-like and have wings and a waxy tail. Eggs are contained in a fluffy, waxy mass. Mealybugs feed on sap from plants. They excrete waste called honeydew, which promotes the growth of sooty mold. Small infestations can be controlled by wiping away the insects with a cotton swab dipped in isopropyl (or rubbing) alcohol or nail polish remover or with insecticidal soap.

http://www.ces.ncsu.edu/depts/ent/notes/Ornamentals_and_Turf/flowers/note19/note19.html

Spotted Wing Drosophila

 

on-raspberry-1024x730

Photo: Jesse Hardin, North Carolina State University

The Spotted Wing Drosophila damages fruit crops by cutting a slit into healthy fruit and laying eggs inside. Spotted Wing Drosophila prefers softer fleshed fruits like berries, cherries, and grapes. These insects are less than 4mm in length, and their larvae can be found inside fruit, causing softness and holes.

How can I manage SWD (Spotted Wing Drosophila) in my garden?
While SWD infested fruit may be unpalatable, larvae are not harmful if consumed. Ripening and ripe fruit are susceptible to SWD attack, but flies do not appear to be attracted to unripe fruit. Good cultural management can reduce SWD damage. Good cultural control includes:
1.Excellent sanitation: fruit should be harvested frequently and completely. Any unmarketable fruit should be removed from the field and either frozen, “baked” in clear plastic bags placed in the sun, or hauled off site to kill or remove any larvae present. When you done harvesting for the season, strip any unwanted fruit from plants and destroy it.
2.Canopy and water management: Prune plants to maintain an open canopy. Do not overwater plants. Leaking drip irrigation should be repaired, and overhead irrigation should be minimized.
3.Exclusion: Fruit can be covered with fine mesh bags or paint strainers prior to ripening to exclude flies. Bags should be tightly sealed. Placing a foam plug between branches and the sealed based of bags is useful to prevent plant damage and maintain a tight seal.
4.Regular fruit sampling: Fruit should be observed regularly for infestation before and during harvest.

While cultural control may be sufficient to reduce SWD infestation below damaging levels, insecticides are currently the most effective tool to reduce or possibly prevent SWD infestation. Insecticides can only be applied to plants for which they are labeled. The label is the law! County extension agents and university
specialists can assist with selecting effective, appropriate insecticides. There are some organically acceptable insecticides available for SWD, but they are less persistent than conventional materials and may need to be applied more frequently. (per http://www.ces.ncsu.edu/wp-content/uploads/2013/04/Homeowner-Factsheet-2013.pdf)

http://swd.ces.ncsu.edu/swd-biology/

This video shows how to make a Spotted Wing Drosophila trap to assess the presence of these pests in your garden.

Finally, Japanese Beetles are active. Beetle traps are more effective at attracting Japanese Beetles than controlling them. If you do use traps, locate them far from plants you wish to protect. Per NCSU: Homeowners can take advantage of the beetles’ aggregation behavior by shaking plants to dislodge beetles each morning. Without beetles already on a plant, it is less likely that beetles will aggregate there later in the day. Picking beetles off by hand will also reduce the accumulation of beetles that results in severe damage. They can be easily knocked into a widemouth jar of soapy water.  In some settings, flowers or plants can be protected with cheesecloth or other fine mesh.

http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note44/note44.html