How do I control cap lice?

Cap Lice are a family of aphids, but they are much harder to control. These small, sticky creatures look like woolly white dots and have a protective shield that makes them resistant to many types of pesticides. Don’t worry, there are plenty of effective ways to fight off cap lice. They are only about 4 millimeters in size and often nestle on the leaves of your houseplant. Once they have settled, they bite into the plant and suck out all the nutrients, which the plant desperately needs. It is crucial to take quick action to save your houseplant.

Preventing Cap Lice

There is no specific way to completely prevent cap lice. However, it is essential to regularly check your plants for unwanted visitors and deal with them immediately when you spot them. This prevents them from spreading further and compromising the health of your plant.

Different Types of Cap Lice

Cap lice can be divided into three different types:

1. Parthenolecanium Corni - This is the ‘common’ cap louse and is found on many different ornamental plants and houseplants.
2. Loccus Hesperidum - Also known as the flat cap louse. This type has a flatter shield and a different color, such as yellow-green, yellow-brown, or light gray with dark spots and speckles.
3. Saissetia Coffeae - The half cap louse, which is just as large as the other varieties but is dark in color. It has a preference for coffee plants and carnations.

Spread of Cap Lice

Cap lice never come alone; the most common varieties are brown or gray in color. They always have legs, except for the fertilized females, which do not. A single cap louse can lay up to 3,000 eggs in a few weeks, all protected under its shield. Cap lice are often carried to new plants via clothing or wind.

Location of Cap Lice on the Plant

Cap lice don’t like to be in the spotlight; they prefer to hide. They often hide well in the plant and are therefore often overlooked. This can be dangerous because by the time you spot the infestation, the plant may already be irreparably damaged. They don’t have a specific preference for a location on the plant but are most commonly found around the veins on the underside of the leaf.

Harmfulness of Cap Lice to the Plant

As mentioned, cap lice nestle on the plant and bite into it to suck out all the nutrients. This causes the plant to discolor, drop its leaves, and grow poorly or not at all. An additional problem of cap lice is honeydew, which is an excess of sugars and a food source for sooty mold. This underscores the importance of quick action once you discover that your plant has cap lice.

Controlling Cap Lice

There are countless ways to control cap lice. You can treat them with spirits, green soap, garlic, cold coffee, and much more. The easiest method is to submerge the plant in water for about 15 minutes. This way, you can remove the entire infestation at once. However, check first if your plant can tolerate this! Spraying with just water won’t help because the shield of the cap lice offers protection. Another effective method is treating them with alcohol. Dampen a cotton pad with alcohol (don’t use sweetened alcohol) and rub all the places where cap lice are present. After about a minute, you can easily remove all the cap lice. Be thorough because if you miss one, there is a risk of a new infestation.

Avoid removing cap lice by hand, as this can spread the eggs and cause a new infestation. It’s important to work thoroughly and carefully when dealing with these unwanted insects.