TeddyGreenFingersHorticultural oil (white oil)
Óleo de verão · efficacy moderate · evidence strong · bees caution_dusk
How it works
A fine oil film blocks the breathing pores of insects and smothers eggs. Purely physical, so no resistance develops.
Recipe
Ready-made summer oil per label, or 25 ml light vegetable oil + 5 ml soft soap per litre, shaken hard and used immediately.
How to apply
Total coverage of stems and leaf undersides, especially in the crevices where scale hides. Citrus: any time growth is not flushing. Deciduous fruit: a winter wash on bare wood kills overwintering eggs.
Targets — pests
Scale, Mealybug, Red spider mite, Overwintering aphid eggs, Whitefly
Targets — diseases
Not recorded — the field is blank rather than guessed.
Supplies: Horticultural summer oil, Potassium soft soap, 5 L pressure sprayer
Days to harvest after spraying: 7
Best months: November, December, January, February
Cautions
Not above 30 C or in strong sun. Never within 3 weeks of sulphur. Avoid on blue-leaved conifers and some ferns.
The thing people get wrong
Scale insects look like dead bumps and people assume the treatment failed - the shells stay glued on after the insect inside is dead. Scratch one off with a nail: if it is dry and hollow, you won it.