The Project Team is well-aware of the concerns an aerial spray operation can create over urban areas and is committed to providing as much information as possible to the public on the timing and location of all spray activities . Notices of spraying will be given no more than 24 hours before a spray is planned through radio, television and newspaper announcements. The weather is the most crucial factor in determining if a spray will occur on a particular day. Successful control of gypsy moth using Btk requires at least 6 hours without precipitation to allow the insecticide to adequately dry and stick to foliage that will be consumed by the caterpillars. If it does rain during this period, some of the Btk will be harmlessly washed away into the soil out of reach of the gypsy moth.
Wind speed is also a critical factor to the actual delivery of the spray from aircraft.
The morning is usually the most calm period of the day, however, spraying can be done with some wind. Specific weather conditions are required to allow the delivery of the insecticide at the desired concentration. Monitoring of weather will be done using the Environment Canada weather network supplemented by ground weather stations to give site-specific weather data. Because of the uncertainty of weather, planned aerial spraying for any particular day may be cancelled at the last minute. Determining the Aircraft Flight Paths Aircraft apply insecticides in a series of parallel swaths over a spray zone.