Insecticides for Georgia Pecan Trees

• Pecan trees become large shade trees in time. Anthony-Masterson/Photodisc/Getty Images

  Healthy, robustly growing pecan trees (Carya illinoinensis) rarely succumb to insect problems, but occasionally aphids or weevils appear in Georgia landscapes, according to horticulturists from the University of Georgia. Ample sunshine, summer heat and fertile, moist but well-drained soil help these trees grow their best and produce good nut crops. Applying insecticides is easiest on small-sized trees. Large plants' heights and volume of leaves and branches makes spray applications difficult, time consuming and labor intensive.

Carbaryl

• Pecan weevils crawl up the trunk of trees. Spraying insecticide with active chemical ingredient carbaryl in mid-August and again in September at Labor Day diminishes pecan weevil problems, according to the University of Georgia. Homeowners need a pesticide license to obtain carbaryl. In stores, look for this insecticide sold as dry crystals for dissolving in water. The local cooperative extension office should have specific product recommendations or names.

Imidacloprid

• Imidacloprid controls various aphids on pecan trees when rainy weather doesn't naturally knock off and kill the pests. Pecans tolerate and grow fine with considerable infestations of aphids, so insecticide treatment is warranted only when lower leaves become heavily covered in black sooty mold from the sticky honeydew residue left by the aphids, according to the University of Georgia. Pecan trees absorb imidacloprid via the roots when applied in liquid drenches to the soil, avoiding the need to spray pecan foliage. This chemical is sold as a systemic insecticide and doesn't require licensing to purchase or apply.

Dormant Oil

• Horticultural oil kills various eggs and crawling insects like scale by smothering them. Dormant oil, typically sold to homeowners as 97 percent paraffini oil, is sprayed on branches, buds and twigs of pecan trees in winter. The oil coating diminishes egg and pest numbers before buds unfurl in spring, reducing infestation problems during the growing season. Garden centers often carry horticultural oil products.