i recently noticed scales on my tree and have used a horticulture oil after reading other posts. Can anyone tell me how long it normally takes before the problem is corrected? Also, do the scales dry up and vanish? How will I know if the problem is rectified?
Wait about 2 weeks and rub your fingers over the scale. If they are dead they will flake off like little flakes. Keep a close eye on it and if you suspect scale again respray. Using the light oil (not dormant oil) it won't hurt the tree to spray 2 or 3 times over several months. Watch for the newly hatched tiny crawlers. They are the easiest to kill. Be sure you sprayed really well in the leaf axils and buds because crawlers can hide in tiny places. Good luck.
Actually a good horticultural oil such as Ultra Fine or Volk oils, kill scale very quickly. After a day you should be able to easily flake the dead scale off by simply rubbing them off, or do nothing at all. When using a horticultural oil caution needs to be heeded. Never spray oils during the heat of the day, as this will cause the tree to drop its leaves. Spraying on a cool cloudy day, or in the early evenings are both safe times to use oils. Lastly, horticultural oil sprays also controls, aphids, mealy bug and spider mites, three common pest on citrus trees. - Millet