Wait 24 to 36 hours to make sure the plants are not sensitive to horticultural oil. Some plants, like junipers, cedars and Japanese maples can be damaged by oil. If there does not appear to be bleaching or yellowing on the test leaves, go ahead and spray the whole plant. Do not spray plants with horticultural oil when it is windy as the oil could drift to other plants that do not need to be sprayed and damage them. This is because the oil will not make good contact with the plant and could be washed off before it kills the scales. When the relative humidity is 90 percent or higher, horticultural oil should not be sprayed on plants because it will not evaporate quickly enough. If the temperature is over 100 °F (38 °C), the plant leaves could be damaged. Alternatively, if the temperature is below 40 °F (4 °C) the oil will not cover uniformly, making it much less effective. The leaves on plants that are stressed or wilting from lack of water are more likely to be damaged when sprayed with horticultural oil. In addition:  Do not spray oil on young, new plant stems or leaves as it will likely damage them. Plants that have been treated with sulfur for fungal diseases within the previous 30 days should not be treated with horticultural oil. The oil could cause a plant-damaging reaction when it comes in contact with the sulfur. Horticultural oil is not very toxic to people or animals but it can irritate the eyes and skin.
اختبر الزيت على ورقة أو اثنتين. تجنب الرش في الأيام العاصفة. لا ترش النباتات والأوراق مُبللة. تجنب رش الزيت في الأجواء عالية الرطوبة. تجنب رش زيت البساتين على بعض النباتات. ارتدِ النظارات الواقية قبل رش الزيت.