I have had a bunch of trouble with scale type insects in the past. Matter of fact, I almost lost my Variegated Eureka Lemon to a bad case of scale. Scale insects are one of the hardest to control in horticulture. There are SO many kinds that affect SO many different types of plants. For instance, you have Tea Scale (Fiorinia theae Green) on Camellias. It is the most common and probably the most destructive insect pest of Camellias. They are sometimes hard to find because they infest the undersides of the leaves. They harm the plant because they suck juices form the plant itself. Symptoms of infestation include yellow chlorotic splotches on the upper leaf surface.
ADULT TEA SCALE
It's almost a gimmee that your camellias will get scale, but you can keep it from progressing to major proportions with proper control measures. Scale infestations are more difficult to control when populations are heavy. You should take action and make spray applications when the first sign of scale is seen. Horticultural Oil sprays and Insecticidal Soaps will help control the scale if applied properly. Always follow label directions. This IS the LAW! Both of these products are considered a contact insecticide. For them to be effective, the plants must be thoroughly covered. This way they smother the insect. Hort oils should only be applied during the Spring and Fall when the temperature is above 40, but less than 85 degrees. Spraying in the heat of the day may result in leaf burn.
When it comes to Citrus, we can REALLY Tip the scales here: Snow Scale (Unaspis citri), Florida Red Scale (Chrysomphalus aonidium), Purple Scale (Lepidosaphes beckii), Glover's Scale (Lepidosaphes gloveri), and Chaff Scale (Parlatoria pergandii). Some of the soft scale insects include Caribbean Black Scale (Saisseta neglecta), Brown Soft Scale (Coccus hesperidium), Cottony Cushion Scale, (Icerya purchasi) and Florida Wax Scale (Ceroplastes floridensis).
Luckily the only scale from this list that I have had to deal with is the Brown Soft Scale and the Cottony Cushion Scale.
I found this interesting information about the Cottony Cushion Scale from the University of Florida Website:
The adult female cottony cushion scale is capable of self-fertilization and lays about 500 to 800 eggs. Eggs are laid within an egg sac and are red and oblong. The eggs can hatch within a few days during the summer months but can take up to two months during the winter. The cottony cushion scale population increases most rapidly during the drier months and requires about four months for a generation. Fortunately, there is a heavy natural mortality among the eggs and the first instar nymphs.
Want to see what one looks like?
These things are usually big enough I can just smash them. They are kind of ugly, don't you think?
BROWN SOFT SCALE
The Brown Soft Scale is what almost took out my lemon tree. Brown Soft Scales are protected from insecticides or sprays by waxy coverings, so spray control measures should be aimed at unprotected crawlers. Spot treatments should be applied when scales are present. Applications of insecticidal soap or horticultural oil will kill scales, but at least three treatments are needed to control an infestation. Repeat every six to seven days until scales have been eradicated. Dead scales do not fall from plants, so you'll have to examine plants to determine whether the scales are dead or alive. Crush the scale - if it's dry, the scale is dead; if the body is juicy or leaves a streak when smeared on a piece of paper it was alive. How's that for being gross?!
The major point I want you to take from today's post is this. Take the time to inspect your plants regularly, the old adage of "An ounce of prevention is worth a pound of cure" really hits home here. Scale insects are a real pain to deal with, if they get out of control it can be almost impossible to eradicate them. Look for anything unusual, small bumps, discoloration, or anything small that is crawling. If you do all this, you too can "Tip the Scales" in your favor!