Question:
Some of the leaves of our Yew Pines have a white, fluffy, cotton-like material on them, while others are very sticky and covered with black mold. I’ve been unsuccessful in washing the foliage off and spraying it with soapy water. What is it, and how do I get rid of it?Answer:
- Your Yew Pines, Podocarpus macrophilia, are infected with Mealybugs.
- Mealybugs are a global pest affecting plants grown both indoors and outdoors. In the Bay Area, they pose few problems except for African violets, orchids, cacti, some indoor foliage plants, and Podocarpus.
- They should not be confused with Woolly Apple Aphid, which attacks pyracantha, cotoneaster, and apple trees.
- The white threads or filaments protect the insect and resemble cotton candy on a stick. There are many different species of mealybugs. The female is a soft-bodied insect, gray in color, oval-shaped, and measuring up to one-eighth of an inch in length. Some species are covered with a white, fluffy, waxy material.
- Additionally, they are wingless and move from one host to another by crawling. The female lays between two and six hundred eggs, while other species give birth to live young.
- The male is small, has wings, and possesses a long, waxy tail.
- Mealybugs are typically found in the leaf crevices at the base of the stems or petioles of plants with long leaves like Podocarpus.
- They are sucking insects that feed on the leaves, extracting plant juices and producing a clear, sticky residue known as honeydew.
- This residue can lead to the formation of Black Sooty Mold. You may notice a steady stream of ants running up and down the main trunk as they use the honeydew as a food source. There are many controls available for Mealybugs; however, they require repeated applications. On houseplants, Mealybugs can be controlled using a cotton swab dipped in rubbing alcohol or a solution of insecticidal soap.
- For Podocarpus, I recommend using Bayer Advanced Tree and Shrub Protect and Feed, as it controls a wide range of insect pests, including Mealybugs, in landscape trees and shrubs, as well as in containers.
- It has a distinct advantage over other solutions because it is applied to the roots annually rather than sprayed on the foliage.
- The insecticide and fertilizer combination is applied to the soil, where it is absorbed by the roots when the soil is watered. Once absorbed, it moves up through the plant, providing year-round protection. It even translocates into the new growth after the initial application. It will take about a week to ten days to work its way up your Podocarpus.
- For large shade trees, it may take up to three months to reach the top. The diameter of the main stem determines the number of stems required in plants with multiple trunks.
- The label provides all the specifics. The fertilizer is essential, as it encourages new growth that covers or masks the unsightly existing foliage; otherwise, the Black Sooty Mold will gradually disappear over time.
- The Bayer Advanced Tree and Shrub Protect and Feed solution is a simple, one-step answer to controlling Mealybugs.