Spring Means the Appearance of Stinging Insects
By Kimberly Schofield
As the temperature warms, we will soon see paper wasps actively constructing nests. There are two species of paper wasps, Polistes exclamans which is brown with yellow markings on the head, thorax and bands on the abdomen and Polistes carolina which is reddish-brown in color. Both have smoky colored wings and are ¾ to 1 inch in length.
In the spring, the fertile queens find a nesting site and begin to build a nest. Paper wasp nests are composed of wood fibers that are chewed and formed into open hexagonal cells arranged in a comb-like shape. The female will lay a single egg inside each nest cell. Their nests are oriented downward and are suspended by a single filament. Their nests can be found in such areas as underneath eaves, in structures, or around plants. Adult paper wasps prey on insects such as caterpillars, flies and beetle larvae, which they feed to developing larvae. This makes them a beneficial insect.
Some Control Options
Non-Chemical Options
Since paper wasps feed on caterpillars and other insects, they are considered beneficial insects and no control is needed. However, some people may be highly allergic to their venom, so removal of the wasps nest is necessary. Nests can be knocked down from eaves using a high pressure water spray.
Chemical Control Options
Also pressurized sprays of insecticidal soaps and oils can be used. Residual insecticides can also be used, such as those containing the active ingredients deltamethrin or cyfluthrin.
Be sure to take precautions when treating, so the wasps will not attack nearby people or pets.
Another stinging group of insects that might cause alarm in areas are swarms of bees. Swarms of bees occur most commonly during the early spring when new queens decide to form a new nesting site. These bee swarms are less likely to be aggressive so we usually do not have to worry about stinging. However, these swarms tend to cause uproars in urban areas, if the nest settles in a backyard tree or on a porch. Also if the bees find a way to invade structures and take up residence in walls or attics, it could lead to a pretty expensive removal. If nests are not removed, the wax, honey and dead bees may produce odors that can attract other pests such as mice, ants, or cockroaches.
Some people prefer to leave their wild bee swarms alone. However if you wish to take action, the safest course is to hire a beekeeper to remove the swarm or hire a professional to eliminate it before they discover a way into structures. For more information about bees, please visit http://honeybee.tamu.edu.
Mention of commercial products is for educational purposes only and does not represent endorsement by Texas AgriLife Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this publication was printed. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.
Excess Rain Means Pesky Mosquitoes
by Kimberly Schofield
Due to the all of the April and May rainfall in Texas, we are now experiencing a higher population of another pest insect, the mosquito. Mosquitoes are a diverse group of flies that are found worldwide, with about 85 species living in Texas.
Mosquitoes develop through complete metamorphosis with an egg, larva, pupa and adult stage. Mosquito eggs may be laid individually or in clusters on the surface of water or in dry locations that will periodically flood. The eggs hatch into larvae that eat bacteria, fungi and other organic debris in the water. The larvae will develop into pupae, which do not feed. The adult stage will emerge from the water to take flight.
Adult male and female mosquitoes feed on nectar, honeydew and fruit juices. The female mosquito will consume blood in order to develop her eggs. This causes the female mosquitoes to be the most DANGEROUS ANIMAL in the world, since they are capable of transmitting such diseases as Malaria, West Nile Virus, Eastern Equine Encephalitis, and Yellow Fever worldwide.
Some Control Options Outdoors:
The number one way to reduce mosquito populations in your yard is source reduction! Mosquitoes need as little as a bottle cap full of water to complete their lifecycle, so all areas where water collects needs to be emptied or changed weekly. If standing water is eliminated in your backyard, then the overall mosquito population in your area will be reduced.
1. Areas containing water should be changed or emptied weekly, such as wading pools, buckets, bird baths, pet dishes, ponds, boat covers, irrigation systems, and French drains.
2. Holes or depressions in trees should be filled with sand or mortar.
3. Leaky pipes and faucets should be repaired.
4. For standing water that can not be drained, one suggestion is to use mosquito dunks containing Bacillus thuringiensis israelensis (Bti) to kill the mosquito larvae.
Mow tall grasses and reduce the amount of foliage to reduce the resting sites for adult mosquitoes. Insecticides can be applied to trees and shrubs, such as those containing permethrin, in order to kill adult mosquitoes.
Some options to prevent mosquito bites:
1. Avoid wearing dark colors, since mosquitoes use visual cues to locate hosts.
2. Avoid exercising or yard work in the heat of the day, since mosquitoes are attracted to carbon dioxide and perspiration.
3. Avoid wearing fruity or floral fragrances in perfumes, deodorants, hair products, or sunscreens, since these scents are more attractive to mosquitoes.
4. Wear long, loose-fitting clothing to avoid mosquito bites.
5. Chemicals can be applied to the skin to prevent bites. DEET, has been an effective repellent that can be applied to the skin to repel mosquitoes. There are also other mosquito repellents on the market such as picaridin, oil of lemon eucalyptus, oil of eucalyptus, and soybean oil-based repellents that can be applied to the skin.
Reminder for Safe Pesticide Practices
It is always important to remind ourselves of proper safety when mixing and applying pesticides. Always keep in mind that just because a chemical may seem like a safe material, when concentrated it will not necessarily be safe or less toxic to humans or other animals! We must do our part to protect ourselves and our environment by reading and following the pesticide label directions!
Personal protection equipment depends on the job and the pesticide label, but some good suggestions are to wear a long sleeved shirt, long pants, waterproof gloves, a wide brimmed hat, waterproof boots, an approved respirator with the right cartridge when mixing dust or wettable powders and safety goggles when applying pesticides.
When mixing pesticides, weigh the material carefully, fill the tank with water until half full, and then add the concentrate while water is swirling. Remember to stand above the fill hole to prevent splashing onto face or eyes. After application, rinse the container three times and pour rinses into a mixing tank.
For application, wait until the pesticide needs to be applied, then read the entire label, and wear full coverage protection required by the label. DO NOT attempt to spray when there are gusting or heavy winds, if rainfall is imminent within 6 hours of spraying or if you are feeling angry and frustrated. Also do not smoke, eat or drink while applying any pesticides.
For pesticide disposal, buy only the amount of pesticide you need for the season. It is important to try to only mix the amount of material needed for the treatment. If there is too much, then apply excess material to labeled site or border row. The improper disposal of pesticide containers can lead to ground water contamination. To prevent ground water contamination, use returnable containers and take them back to the dealer when empty. If non-returnable containers are used, then triple-rinse the containers immediately after use (residue can be difficult to remove after it dries) and pour it into the spray tank. Puncture non-returnable containers and store them in a covered area until they can be taken to a container recycling program or a permitted landfill. Contact the Ag Container Recycling Council at http://www.acrecycle.org for more on a recycling program. If bags are used, shake them out, bind or wrap them to minimize dust, and then take them to a permitted landfill.
In case of spill, remove contaminated clothing and wash chemical from skin with soap and water. Launder contaminated clothing separately from other clothing. Follow recommended cleanup and sanitization procedures printed on the pesticide label. Contain spill with containment soil, soda, or absorbent materials. Use cat litter, clay sawdust, soda ash or absorbent cleaning compound to soak up excess pesticide. Always have someone with you as you apply pesticides, in case of an accident. If symptoms of poisoning arise, seek medical help and take the pesticide label or container with you to the hospital.
Pine Sawflies on the Loose!
An outbreak of pine sawflies defoliating pine trees in Lamar, Kaufman and Hunt counties have been reported, mainly on the loblolly pine. It has been tentatively identified as blackheaded pine sawfly, Neodiprion excitans. The blackheaded pine sawflies cause periodic, widespread defoliation of pines throughout the southern United States.
Sawflies are the only suborder of wasps, in the order Hymenoptera, that are plant feeders. The larvae are greenish in color with dark longitudinal stripes and orange to black heads. These larvae can chew the needles down to the fascicles at the base of the needle bunches.
According to the Texas Forest Service entomologists, Joe Pase and Dr. Don Grossman, most affected trees should recover and re-leaf with no treatment. According to Pase, “The larvae feed mostly on 2nd year needles and leave the current year’s growth intact. The result is that few trees die from the defoliation. When tree mortality occurs, it is usually from attacks by pine engraver beetles (pine bark beetles) responding to stressed trees. Even then, few trees are attacked by pine beetles. Because the new growth on the trees this year has not progressed very far, the trees look especially bad, but I think most of them will come through OK – they just need a little time for the new growth to develop.”
If you feel that chemical treatment is necessary, then applications of carbaryl or a pyrethroid insecticide such as those containing bifenthrin or permethrin are suggested. A power, or hose-end, sprayer may be necessary to treat taller trees. Sprays should not be applied when wind speed is greater than 5-7 mph, in order to avoid drift. The services of a professional arborist will be needed to treat large trees. Note that B.t. and spinosad are not effective against sawflies, since they are not true caterpillars.
There is usually more than one generation a year, so watch for additional feeding in late May or June. Trees that have been previously attacked may experience re-infestation by the 2nd generation. However, diseases and natural enemies usually keep later sawfly generations under natural control.
Sources: Joe Pase III, Entomologist, Texas Forest Service, jpase@tfs.tamu.edu and Mike Merchant, Texas AgriLife Extension Entomologist, http://insectsinthecity.blogspot.com/.
Mention of commercial products is for educational purposes only and does not represent endorsement by Texas AgriLife Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this publication was printed. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.
Kimberly Schofield
Program Specialist-Urban IPM