Why are your croton leaves turning yellow and dying? It could be that you have Croton Scale. What is Scale? Although it sounds like a disease, Scale is actually the name of a few thousand different insects that suck the life out of plants! There are 8,000 different species of scale and all belong to the family Coccoidea. All these species are broken down into 3 groups. Soft-bodied, Hard-bodied, and Armored.

So, what's with the name scale? The name is given because of their scaley or shell-like coating that protects them. They are closely related to aphids but look more like blisters on plants if you aren't looking carefully. Similar to aphids, they are sap sucking insects and some species even make honeydew as a biproduct like aphids do. By penetrating the plant, they make the plant more susceptible to disease. In large infestations, they reduce the ability of the plant to provide nutrients to its leaves causing them to appear diseased and eventually die.

Croton scale is a relatively newly discovered scale. Discovered in South Florida in the early 2000's, there are not very many publications that provide sufficient information on them. Even management is still somewhat unclear. As with most insects, Scale species have different host plants. Meaning that this Scale may not be problematic to other plants in your garden. But other species of Scale may be.

So, what is the recommended management? First, let’s discuss how scale even gets to your plants and how you can prevent them. Interestingly enough, adult Scale are generally immobile. They don't really move from their feeding location. Nymphs on the other hand, are mobile and will leave their hatch site in search of a good place to feed.

So how do Scale insects find their desired plant? I am not 100% sure. There may be an answer out there that I just can't find. Some online resources talk about nymphs moving far distances by wind, humans, and even birds. Another resource points out that storebought potting soil, or plants from a nursery that has a Scale infestation may bring them into your garden.

Once they are in the garden, they can prove tough to deal with. The waxy shell-like coating makes them resilient to pesticides. Currently, Horticulture Oil is the recommended treatment. Horticulture Oil is really only effective against nymphs and less likely to reduce adult Scale numbers. Horticulture Oil works through direct contact so care must be taken to treat the entire affected areas of plants. Most experts say that systemic plant treatment by certain pesticides through root absorption is the most effective. However, this treatment can take some time to work and likely will not save a plant that is heavily infested. You can find more information about systemic treatments on various websites, and I don't want to pretend like I know enough about them to give recommendations.