ISSUE 10 July 6, 2000
MOSQUITOES FLOURISH WITH RAINS
With all the rainfall in the past three weeks, mosquito populations are building rapidly. Typically, adult emergence of mosquitoes gets underway 10 days following the flooding rains. In the southern Red River Valley, the rains from two weeks ago have brought on large populations just in time for July 4th. Communities and farmsteads around the region are experiencing the same problems.
Many attempts to manage mosquitoes focus on controlling the larvae. This is the time when they are confined and most concentrated. However, with the saturated soils and most recent rains, there can be numerous breeding sites around, and difficult to treat them all adequately. Where standing water is a problem around the home or farmstead, treatment programs may use Bacillus thuringiensis var. israelensis (sold as Mosquito Dunks®,
Bactimos®, Teknar®, and Vectobac®) and methoprene (Altosid). Mosquito Dunks® are packaged as briquets and are slow release (working for about 30 days). Also, they remain effective even with the alternate wetting and drying that occurs in these ponding sites. Local availability of the products may be the challenge.
Controlling adult mosquitoes is a big task because of their mobility. Generally, the larger the area treated, the more successful the control. Even then, the results are temporary, as new adults migrate into the area or emerge from breeding sites. Around the home, control is most practical for short term reductions of mosquitoes, such as for a summer picnic. In those cases, treat 12 to 24 hours prior to the event. This insures the spray has dried on
vegetation before people are present. It will also reduce the mosquito population before the guests arrive.
For most homeowners, sprays containing malathion , carbaryl (Sevin®), permethrin, and resmethrin should be directed at vegetation where mosquitoes rest during the day. Treat at dusk or early in the morning. Around a farmstead, there is one other option. Farmers who use Tempo® to treat grain bins will discover, when they read the label, that this product is approved for use to treat landscape areas (shrubs and tall grass) for the control of
several nuisance pests, including mosquitoes. This product should be used only by licensed applicators. It is NOT approved for application to edible crops in the garden.
Municipalities that are looking into treating for mosquitoes have two options for the method of application, ground or air. Ground applications are made as ULV (ultra low volume) or thermal fogs. Aerial applications also use low volumes. If a municipality is considering aerial treatment there are two agencies that MUST BE CONTACTED:
FAA Flight Standards District Office
Fargo, North Dakota
The pilot must complete an application that describes the aircraft, the pilots experience, the area to be sprayed and potential flight hazards.
North Dakota State Department of Health
Air Quality Division
Bismarck, North Dakota
The municipality to be sprayed must obtain approval. Information required includes: target pest; aerial applicators name, address, and phone, name of insecticide, concentration, rate and method; proposed date of treatment; date and method of public notification; and signature of public official accepting responsibility.
Insecticides approved for these types of applications include: malathion, permethrin, resmethrin, and naled. Because public health issues are a factor, applicators need to be knowledgeable and competent in this field.
Finally, the best protection from mosquitoes is still the use of personal repellants containing DEET. Protection lasts from 1 to 5 hours. Follow these general guidelines for their use:
- Read all directions before using this product;
- Do not spray in enclosed areas;
- Do not apply over cuts, wounds, or irritated skin;
- Do not apply to eyes and mouth;
- Do not apply to the hands of young children;
- On children, use a product containing less than 20% DEET. Do not spray directly over the face;
- Avoid breathing DEET aerosol;
- Do not use near food.
Use just enough repellent to cover exposed skin and clothing. Do not use under clothing. Reapply as necessary, but avoid overexposure.
WHEAT MIDGE EMERGENCE UNDERWAY
IN NORTHERN COUNTIES OF NORTH DAKOTA
All regions of the state where wheat midge are established have emerging females present. It is time to intensify scouting in central counties where peak emergence is underway. In northern counties, female emergence is just getting underway. Peak emergence in these areas would be expected early next week. If wheat fields are heading, then scouting in the evening is important. Due to the lower populations across the area, it is expected that fewer fields will have great enough numbers of midge to justify control. Finding those fields where populations are at threshold will be more of a challenge.
EUROPEAN CORN BORER MOTHS EMERGING
European corn borer moth activity had been relatively low based on blacklight captures. That is now beginning to change. Moths are being captured more regularly and at higher numbers throughout the southeast areas of ND. In emergence cages holding infested stalks from last year, moth emergence has been very consistent biginning with the past weekend.
It is time to begin monitoring corn for first signs of egg laying and early larval feeding. Next weeks newsletter will review treatment thresholds and decision making for ECB control..