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Conference paper, 2007

Use of oil and/or soap in spray application to control pests in fruit and berry production

Björkholm, Anna-Mia; Nilsson, Johan; Svensson, Sven Axel


Use of oil and/or soap in spray applications to control pests in fruit and berry production Björkholm, A-M; Nilsson, J; & Svensson, SA Department of Agriculture, SLU Alnarp, Sweden Pesticides with physical mode of action, like oils and soaps, have a long history in plant protection against pest in fruit and berry crops. Although modern agrochemicals are widely used for crop protection, oils and soaps have been reconsidered as useful pest control agents or as base mixtures with plant extracts and other natural substances, for the past years, especially in organic production. They are environmentally friendly, but harmful to many pests. However, pesticides with physical mode of action are effective only when they have a direct contact and thorough coverage on the targets. Their practical use is frequently questioned by growers, due to great variations in control efficiency. The presumption is that the unsteady efficiency of oils and soaps can be explained by the general application quality in practice, which is not corresponding to the pesticide demands. This is likely to be true for dense canopies such as fruit and berry crops. The objective of this research was to determine effective application methods that could increase spray penetration, deposition and coverage in fruit and berry crops, aiming for efficient biological control. Investigations were focused on three crops: strawberries, raspberries and fruit trees. For each crop, experiments were conducted with different application parameters in growers’ fields. In an introductory Master Thesis, the concentration factor was studied in experiments with six spray mixtures containing combinations of physical (oils or soaps) and chemical (plant extracts) acting pesticides to control white flies (Aleurotrachelus socialis) in cassava Manihot esculenta. Pesticide concentration influenced, as expected, the general mortality. Further more, different pest development stages were more sensitive to certain pesticide types. Before field experiments, tests were also conducted to determine how to use the soap as an emulsifier to make stable oil-water mixtures, often regarded as a problem by growers. In cooperation with Department of Physical Chemistry, Lund Institute of Technology, Lund, Sweden, stable and uniform spray mixtures were obtained with a standard sprayer agitation when a pre-mixture of soap and oil with the ratio of 1:1 was used. The efficacy against aphids and thrips in greenhouse was then investigated with different concentrations of spray mixtures containing the oil and soap. High application rates were required to reach full coverage even if the pests were fully exposed. In field experiments, raspberry beetles (Byturus tomentosus) were treated with oils which is a normal practice in organic raspberry production. A vertical boom sprayer with Twin Cap nozzles (Lechler) was used. One nozzle produced a coarse spray quality (for penetration) and the other a fine spray quality (for coverage). Other tests included air assistance and various nozzle types and application rates, studied with fluorescent tracers. Strawberry thrips (for example Frankliniella occidentalis) were treated with soaps which is a normal practice in organic production and occasionally in Integrated Production. Band sprayers of three nozzles per row were used to deliver sprays with different mixture concentrations and application rates. In other experiments, comb- or finger-like crop openers in combination with nozzles directed in different directions were also tested to improve spray penetration into dense strawberry crops. In organic apple production tests, oils were sprayed with standard sprayers to control aphids, spider mites and different moths (for example, winter moths Operophtera brumata and codling moths Cydia pomonella). Spray penetration, coverage and deposition were studied with various application rates, nozzle types, spray qualities and other factors. Along with the investigation of pest control efficiency, the risk of harming beneficial fauna by spraying oils and soaps was also investigated in the past season when fauna samples were collected in raspberries


application technology; oil and soap;

Published in

Book title: 9th Workshop on Sustainable Plant Protection Techniques in Fruit Growing - SuProFruit - Book of Abstracts
ISBN: 978-91-85911-09-7
Publisher: Swedish University of Agricultural Sciences


9th Workshop on Sustainable Plant Protection Techniques in Fruit Growing - SuProFruit

Authors' information

Björkholm, Anna-Mia
Swedish University of Agricultural Sciences, Agrosystem
Mickelåker, Johan
Swedish University of Agricultural Sciences, Agrosystem
Svensson, Sven Axel
Swedish University of Agricultural Sciences, Agrosystem

UKÄ Subject classification

Food Science
Agricultural Science
Fish and Aquacultural Science

URI (permanent link to this page)