Thus far our spring has been mild in temperature and blessed with periodic moisture. These mild conditions have helped many trees produce abundant foliage. Abundant foliage may look pleasing, but can also offer an expansive pallet of food for many chronic insects like aphids, mites, and scales. The insects can have multiple generations in a single season, which offers them the ability to respond quickly when ample food is available.
Aphids will congregate where the feeding is easiest. This includes unopened flower buds, the underside of young leaves, and on developing stems. Feeding by aphids can sometimes discolor leaves, distort or curl foliage, and form galls. When large populations feed for an extended period of time, aphids can cause wilted leaves, stunted shoots or shoot dieback. As aphids feed, they inject saliva into their host plant which helps digest the sap. The pre-digested sap is sucked up by fine needle-like mouth parts of the aphid. A large portion of this undigested material is excreted through a waste product called honeydew. Honeydew is often described by our clients as “something dripping from my trees.” Several additional pests will seek out this sugar rich excretion. A few of these secondary pests include ants, yellow jackets, and a disease called Sooty Mold. Honeydew will coat bark, leaves, and objects beneath the plant, including car windshields and patio furniture, leaving a sticky mess.
Mites cause damage by sucking cell contents from leaves. A small number of mites usually isn’t reason for concern, but very high populations – levels high enough to show visible damage to leaves – can damage plants, especially herbaceous (not woody) ones. At first, the damage shows up as a stippling of light dots on the leaves; sometimes the leaves take on a bronze color. As feeding continues, the leaves turn yellowish or reddish and drop off. Often, large amounts of webbing cover leaves, twigs, and fruit. Damage is usually worse when compounded by water stress.
Our Integrated Pest Management (IPM) programs are designed to preventatively and therapeutically control pests like aphids and mites in order to maintain a healthy landscape without the over use of pesticides.