A friend remarked the other day, “Your bay-tree has scale.” I hadn’t quite pin-pointed the problem, it just looked slightly black & mouldy. With some trepidation I goggled his suggestion of white oil, hoping it wasn’t chemical based. Surprise surprise, it was just oil & detergent, once mixed it goes white, daar, that was obvious.
White oil: 1/2 cup cheap vegie oil, 1/8 cup mild (uncoloured) dish detergent
Mix until white (emulsified) & dilute for use, 25ml to 1 litre of water. Place in a spray bottle, shake, generously spray all over & under affected plant–on a mild temperature day.
Apparently it suffocates the scale insects, that gather around joints, stems & under the leaves. The scale secrete honeydew on the leaves, attracting ants & also cause the sooty mould or black fungus to grow.
Looks pretty tragic but I have just sprayed it- I will wait with baited breathe for a result!