HelpfulGardener.com

Hi,


I live in northern California.

My orange has been having this problem since I bought this house two years ago.with white cotton-shaped thing on the back of the leaves and black "dusts" on the front of the leaves that are infected.

The tree still bore oranges every year since I moved in but I would like to get rid of the problem since it's spread to my lemon tree nearby.

I tried safer Insect Killing Soap but it didn't help.

Could someone please help me identify the disease and recoommend a solution?

Thank you.

Dominique
[img]https://img85.imageshack.us/img85/6991/imgp7331.jpg[/img]
[img]https://img85.imageshack.us/img85/3548/imgp7333.jpg[/img]
[img]https://img196.imageshack.us/img196/787/imgp7338.jpg[/img]

This is just a wild guess, since I haven't seen the tree, but could it be cottony cushion scale? Here's an article by the UC Davis Extension Service that includes a picture of the insect:

https://www.ipm.ucdavis.edu/PMG/r107301611.html

The black stuff might be sooty mold, which commonly grows on honeydew, which is secreted by insects such as scale, aphids and whiteflies. Here's a link to just one article about it:

https://collier.ifas.ufl.edu/CommHort/CommHortPubs/Sooty%20Mold__2005.pdf

Thank you both for the information.

The infection is pretty wide spread.

The white stuff is only seen at the back of the leaves. Not at the front of the leaves, branches or trunks.

Since I am new to gardening, could someone please give me a specific product I can use (e.g. brand and name of the spray)?

And what pictures would be helpful in correctly identifying this disease? I can upload more.

Thanks a lot.

Dominique

I have the exactly same problem on my orange tree, don't know what to do, seems like the new leaves is healthy, so I try to cut out the infected leaves as much as possible, and the wash the black mold away from orange, it's really annoying, the white powder fly out when I touch them get closer. is there any better way to get rid of them?