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Working towards more efficient application of pesticides
Author(s) -
Matthews Graham A,
Thomas Neale
Publication year - 2000
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/1526-4998(200011)56:11<974::aid-ps231>3.0.co;2-4
Subject(s) - pesticide , environmental science , arable land , pesticide application , agricultural engineering , sprayer , integrated pest management , crop , environmental engineering , agronomy , agriculture , ecology , biology , engineering
The present status of Integrated Crop Management requires the judicious use of pesticides to optimise yields. However, considerable concern about the possible impact of pesticides on the environment and the need to minimise the dosage applied has led to a conflict between the requirements for efficient application and avoiding spray drift. The requirement for no‐spray buffer zones for certain pesticides has encouraged wide‐scale adoption of coarser sprays to reduce downwind drift. However, use of larger spray droplets in coarse sprays does not always provide efficient delivery of a pesticide to foliage, so a higher dosage may be required to achieve effective pest management. Within treated fields a higher proportion of the pesticide may be lost to the soil when coarse sprays are applied, thus increasing the risk of adverse effects, such as infiltration and potential risk to ground water within a treated field. The need, therefore, is for a method of optimising pesticide delivery whilst minimising the risk of both exo‐drift downwind to neighbouring land and endo‐drift losses within a treated field. One approach is to optimise nozzle selection for most of the field and change to a coarse spray for the downwind edge of the field, while the area treated within a field can be restricted to the specific parts infested with weeds by patch spraying. Some farmers now use air assistance to improve projection of spray droplets into a crop canopy, especially the downward‐directed air curtain used in arable crops, but many food crops have a complex crop architecture which requires a more site‐specific targeting of a pesticide if minimal dosages are to be applied. A new nozzle concept directs a fan‐shaped air jet at a shallow angle at the spray sheet emerging from a hydraulic nozzle. This affects droplet production and provides a finer spray entrained within the air flow directed at the crop. Wind tunnel assessments with a prototype nozzle indicate less potential drift despite application of smaller droplets. The main advantage of linking the air flow to individual nozzles is that they can be positioned to project spray more selectively in relation to crop architecture and pest habitat. © 2000 Society of Chemical Industry