Control of Insects and Mites on Ornamentals

DRESENT INTEREST in grow' ing ornamental plants has created a demand for information on the control of the insects, mites and other pests attacking them. Requests for this information come from home gardeners, florists, nurseries and contract applicators. Until recently very little attention was given the problem since there was no satisfactory way of estimating monetary losses of ornamentals due to insect depredations. Ornamental plants are subject to attack by many species of insects. To maintain shrubs and trees in a healthy, attractive condition it is usually necessary to protect them from insect pests. Because many of the newer insecticides are often specific in controlling insects it is important to learn how to recognize the specific pest. This is helpful to understand the actual importance of the insect and to decide on the best measures for control. The following information is intended to serve only as a guide to help combat some of the general insect problems. It is not possible to include a long list of specific insects or the list of host plants. Whenever ants are observed in numbers on a plant one should suspect the presence of soft scales, mealybugs, aphids or whiteflies. These sucking insects excrete a sweet liquid called "honeydew" which is attractive to ants. This sticky material is unsightly and makes an excellent medium for the development of a black fungus called "sooty mold." The presence of this fungus also should cause one to suspect that the plant is infested with one of these insects. This fungus retards the growth of the plants to some extent by reducing light, thus interfering with By DR. L. C. K U I T E R T