How do I treat scale on our agapanthus, grevillea and gardenia?
We live in a wet area of south east Queensland (Peachester in the Sunshine Coast Hinterland). The area is generally cool and wet - to date we have received 1.4 metres of rain for 2013. We have found a black scale appearing on the leaves of our agapanthus, some prostrate grevillea and gardenia. Co-incidentally, the affected plants are growing near large infestations of bird nest fungus. We are not sure if there is any relationship between the two. I have a photo of the scale on a grevillea leaf. I can also provide a photo of the fungus.
Thank you for sending the photo. It does look like brown olive scale. This scale can be seen on both the leaves and stems of the plant. Early summer is the peak egg hatching time with another generation hatching in autumn. If it is scale, you will notice a lot of ant activity as they will be attracted to the honeydew that is produced from this sap sucking insect. When you mention the fungus on your birds nest, I am wondering if you are confusing it with the spores that are produced underneath the leaf of the birds nest. If you could send a photo, that would be good. Thank you.
From your friends at Yates Gardening
Answered: 8 Mar, 2013