D.G. Embree


Executive Summary

This report is written as a response to the 1991 survey, the Improved Pesticide Applications Wish List conducted by the Forest Pest Management Institute ( now Great Lakes Forestry Centre, Canadian Forest Service, Dept. of Natural Resources, Canada) at Sault Ste. Marie, Ont.

Of the 52 "wishes" related to insecticides, and 59 similar "wishes" for herbicides, the first priorities to be addressed were the needs for the development of:
1. improved operational spray block and swath marking techniques to guide the spray pilot ( ie. to assist the pilot to position the aircraft accurately in relation to the previous swath, and boom on and off at the proper time;
2. a guidance and marking system for ground sprayers to ensure that successive swaths are correctly spaced, and
3. a system that would record spray aircraft performance in relation to specific points within a spray block ( air speed, ground speed, height, spray mix flow to boom, wind speed, wind direction, booms on and off, temperature, boom pressure, atomizer rpm, Loran C or GPS position, line number, and relative humidity).

The most obvious response to these priorities is the use of Differential Global Positioning Systems which provide incredibly accurate position fixes from signals emanating from a complex of satellites and fixed ground station towers. Associated guidance equipment enables spray aircraft to be flown directly to spray blocks. Visual displays define spray lines and the respective position of the aircraft. Flight patterns in relation to spray areas and swath lines are recorded and can be displayed on computer printouts. Similar equipment is available for ground sprayers.

Rapidly changing technology has made available a number of visual aids which are designed to enable spray pilots to maintain steady flights over variable terrain while at the same time observing and operating computer equipment. The suitability of each of these aids has not as yet been fully assessed. Proper training and aptitude of pilots are essential for the implementation of this technology.

The limited distribution of ground station towers, also a problem, is expected to be solved beginning in 1997 through an increase in the number of towers and the establishment of a master control station for North America. The rapidly changing technology suffers from growing pains, and although a number of additional problems exist, there appears to be no underlying reason a completely workable and efficient technology can't be developed.

Appendices to the report summarize the salient features of spray navigation equipment of 11 manufacturers.

Spray deposit models PKBW2 (Picot, Kristmanson, Basak-Brown, Wallace), FSCBG ( Forest Service, CramerBarry- Grim) and AGDISP( AGricultural DISPersal) have the capability of determining where the spray cloud is likely to go. The difficulty of measuring air stability, and wind speed over the spray block is a problem, but not an unsolveable one.