Bumps on Branches of Magnolia
Will you please look at the attached photos and tell me if you know what is attaching itself to my tree. It is a pink magnolia or I have heard it called a "tulip tree." It looks like little bumps all over the tree. When I pull them off them are filled with black stuff and a red liquid. I'm worried it will kill my tree.
The branches of your magnolia are covered with scale. This common pest of magnolias can be very difficult to control. The insect’s hard shell covering protects it from weather, many pesticides and predators.
These insect suck plant juices causing leaves to yellow and brown. Severe infestations can greatly stress the tree causing twigs and stems to die.
The scale insects secrete excess plant sap as a clear, sticky liquid called honeydew. This honeydew often drips onto surrounding leaves and twigs. Sooty mold often grows on the honeydew resulting in blackened leaves and stems in summer. The honeydew and sooty mold do not directly harm the plants, but the sooty mold blocks the sunlight causing the fungus covered leaves to yellow and eventually drop. The clear sticky honeydew, sooty mold as well as the ants, bees, wasps and flies that feed on the honeydew are additional things that are often observed with this pest.
Knowing the insect’s life cycle will help with control. The females lay their eggs under the hard scale covering. The eggs hatch into translucent immature scales, known as nymphs or crawlers, that are most active in September. These crawlers move around the tree looking for a place to feed. This is a good time to use several applications of eco-friendly products like insecticidal soap or Neem to kill the crawlers.
Dormant oil sprays can be used in late winter before buds swell and growth begins. Be sure the temperatures are at least 40 degrees when you spray and for the following 12 hours. Otherwise you can cause more damage to the tree than the scale insects.
Systemic insecticides like Bayer trees and shrub insecticide are available. These are applied to the soil, absorbed by the plant and eventually kill the scales.
No matter what type of control method you use, timing is critical for success. And as always be sure to read and follow label directions carefully.
Best of luck as persistence is also key to controlling this pest.