Fysikaliskt verkande växtskyddsmedel

Physically active pesticides, such as mineral oils, vegetable oils and soaps, have been used by integrated and organic fruit and berry growers in recent years. The use will most probably increase, as one of several future tools to replace and complete some of the chemical pesti-cides. Physically active pesticides can be effective only if they contact pests thoroughly, un-derlining the importance of high quality application technologies. The objectives of the project are, based on applied research, to produce knowledge of physical active pesticides and of suitable application technology for these, within fruit and berry pro-duction. The effect on the beneficial fauna should be studied as well. Series of experiments were carried out; evaluation of pesticide efficacy in field experiments, determination of application rates, laboratory studies, survey of fauna population, construction of sprayers etc. Variables investigated were dosage, concentration, application rate, and appli-cation method. Most field experiments were conducted at commercial farms. One study shows that a stabile oil spray liquid, without tendencies to separation, was obtained by premixing oil and soap (emulsifier) at a 1:1 ratio. Oil spray was applied to control rasp-berry beetle (Byturus tomentosus) in a field experiment. In general, efficacy results were promising, although dosage and application rate were not correlated. The effect on beneficial fauna was not significant while a small difference was noted between treated and control plots. Apple coddling moth (Cydia pomonella) was treated in a pilot study (without replica-tion), showing a limited reduction of the pest. Several evaluations of spray liquid penetration into canopies were made in strawberry, rasp-berry and apple. A fluorescent tracer was added to the spray liquid to quantify deposits. The application quality on sprayed leaves were analysed and visually graded with UV-light. Test results indicated that spray deposit was insufficient at the lower leaf surfaces in the canopy centres, despite of efforts with locating nozzle at different positions, using crop tilters, or in some case using the air assistance. The best deposition result was achieved in apple canopies, probably because air assistance already was used as a standard procedure. Research reports, completed by field and laboratory studies, show that physical active pesti-cides have effects on pests. The effect is however limited, compared to traditional chemical pesticides. This implies a number of high demands within different disciplines; demands that have to be fulfilled to achieve the sufficient effect. Action should only be made against insects with sensitive stages in their life cycle, and they have to be exposed enough to be targeted by the spray liquid. This requires increased knowledge on behaviours of pests, further developed prognosis/warning systems, and, eventually, repeated spraying with sophisticated application methods. Importantly, further research is needed, including completing plant protection ac-tions with different mechanisms, as pheromones, support of beneficial fauna and other pre-cautious contributions.