It may be after Labor Day, but some of your plants may still be wearing white, breaking that long-standing fashion “rule”! While many of us don't adhere to this old rule for our wardrobes these days, you may care about white stuff on your plants this time of year. 

There are several white colored pest insects and diseases that you could be noticing on your plants.

Scales

Several types of scale insects are white. Each has their own host preferences, or plants they feed on.

• Cochineal scales feed only on cacti, usually prickly pears. On the outside they are white and waxy but...