Getting the best out of Spray Oils

To get the most out of an insecticidal spray oil, you should be observing these universal rules:

• Read the label carefully and follow its directions!

• If permitted, apply low rates often, rather than a high rate once

• Use a high spray volume to ensure good coverage on the target plant parts

• Make sure the spray tank is well mixed, but don't overdo the mixing. You don't want the emulsion so stable that when you spray it, the oil doesn't separate from the water and runs off the leaf.

• Target the undersides of leaves where pests like mites, whitefly and aphids tend to congregate

• Target vulnerable life stages of pests like eggs, early instar larvae and crawlers. Usually this is in early spring time for most pests.

• If your crop has a history of a certain pest and you observe a few of them around, spray at that point with a low rate, and follow up again in 7 - 10 days. Don't wait for the population to build up to high levels.

• For summer applications, apply the oil in the evening after the plant surface has had a chance to cool slightly from the daily heat. The next best time to spray is early in the morning before the sun gets up in intensity.

• Avoid spraying oils on plants with a valued bloom appearance e.g. table grapes. The oil will flatten the bloom changing the appearance.

• Spray oils work very well in combination with other soft products like Bt's.

• Don't use disruptive insecticides, like organophosphates or synthetic pyrethroids because these often cause secondary pest outbreaks or subsequent pest 'flaring'. This is because they kill beneficial insects which were helping to control the pest in the first place.

• Don't spray oils if sulphur-based products have been used in the previous 3-4 weeks or are likely to be used in the following 3 weeks.