Tracing insecticide spray droplets by sizes on natural surfaces. The state of the art and its value

Abstract

Recent trends in integrated chemical and biological pest control call for further refinement of the effectiveness of existing chemical pesticides by more efficient spray application. One aspect of improving spray efficiency is by the use of the correct range of droplet sizes. In this way the volume of spray, and the amount of active ingredient used, particularly in ultra-low volume techniques, can be further optimised, and when combined with correct application time, gives maximum biological efficiency with minimum disturbance of the environment. This necessitates a study of the size spectrum of droplets deposited on rigorously defined biological targets which in turn calls for an investigation of suitable tracer methodology. Additional details of the previously published fluorescent particle method are discussed, and its reappraisal shows that it is a unique method capable of estimating droplet sizes on all biological surfaces, especially insect larvae. The reversibly soluble fluorescent pigment method based on the relative balance between soluble and insoluble state of the pigment proves highly successful in imprinting fluorescent droplets on broad leaves, particularly on cotton.

Determining the drift potential of Venturi nozzles compared with standard nozzles across three insecticide spray solutions in a wind tunnel

“…If optimised for drift avoidance, this can also reduce environmental losses. 26 Increasing concerns of pesticide spray drift exposure has encouraged the adoption of nozzles using a venturi process to entrain air into the spray. 27 These so-called air-induction (AI) nozzles often also utilise a pre-orifice chamber to help increase the droplet size and act as drift-reducing technologies (DRTs).…”

A conceptual model for assessing ecological risk to water quality function of bottomland hardwood forests

“…Numerous studies conducted to quantify spray drift (Himel and othes 1965, Barry and Ekbald 1978, Uk 1977, Wiesner 1984 have determined that drift is a probability problem driven by wind speed and direction, droplet density and size distribution, evaporation rate, volume and amount of pesticide applied, and atmospheric turbulence, thus making it extremely difficult to predict inadvertent pesticide inputs to uontarget ecosystems. However, the potential of nontarget BHRE receiving spray drift appears to be large because target agricultural areas are commingled and contiguous to BHRE throughout the TVU landscape.…”

THE DISTRIBUTION AND RECOVERY OF AERIAL ULTRA‐LOW VOLUME SPRAYS FOR CONTROLLING NYMPHS OF THE AUSTRALIAN PLAGUE LOCUST, CHORTOICETES TERMINIFERA WALKER

“…In addition, their use has certain advantages over the use of techniques of tracin droplets on natural surfaces with fluorescent pigments (Himel 1969;Himel and Uk 1975;Uk 1977). The fatter can yield more accurate information on spray de osit, but they are not particularly suitable for large-scale field use, as in these trials, because they require eLborate preparation of the spray mixture and analysis of the samples.…”