they are in a garden bed with roses and citrus could this be a transfer of disease from them
21 November 2011 12:36 AM
It is likely the black sticky substance on the leaves is Sooty Mould. There would have been at some stage a sap sucking insect e.g scale, aphids or thrips on your tree. The leaves and shoots fed on by these insects tend to wilt, become twisted and curled. When feeding, they produce honeydew, a sticky substance which over time develops into a black sticky coating on the leaves. Other plants in your garden such as citrus, roses and other ornamentals can be attacked also by these insects. You can control insects eg. aphids, thrips, mealybug with products such as PestOil, Yates Nature's Way Vegie & Herb Spray Concentrate on edible crops. There is a 1 day withholding period with PestOil and no withholding with Yates Nature's Way Vegie & Herb Spray Concentrate. At this time of the year it is always best to monitor the plants in your garden for insects and get them under control before they get out of control. Keep your plants healthy by regular watering and fertilising which will help to keep those nasty pests at bay.