Forest Pests: Insects, Diseases & Other Damage Agents

Oak Pests: A Guide to Major Insects, Diseases and Chemical Injury

Solomon, J.D., et al. 1987. Oak Pests: A Guide to Major Insects, Diseases, Air Pollution, and Chemical Injury. Protection Report R8-PR7. USDA For. Serv., Southern Forest Expt. Sta. 69 p.

Introduction

The oaks (Quercus spp.) are among our most valuable hardwood resources, amounting to one-third of the hardwood sawtimber volume in the United States. Over half the annual cut of oak lumber is produced in the 13 Southern States. Oaks are best known for their timber production and resulting fine furniture, beautiful flooring, and other products. Yet aesthetics, watershed management, recreation, and wildlife are goals now given equal or greater priority by many. The oaks are valued for shade and ornamental purposes – a single tree sometimes adds thousands of dollars to real estate values.

Insects, diseases, and pollutants present a continuing threat to oaks. A major portion of the acorn crop is destroyed during some years – hampering regeneration efforts. Seedling mortality and dieback add to this problem. Terminal and top injury adversely affect tree form. Repeated defoliations cause growth loss and mortality. Borers and decay cause defect and degrade amounting to an annual loss of millions of dollars. Indirect losses occur through disruption of sustained forestry practices, regulation of forest types, and altered wildlife habitat. Homeowners may incur the expense of chemical control and possibly the cost of tree removal if mortality occurs. Nuisances created by numerous insects decrease tourist use and revenue.

It is far better to prevent attack by insects and disease than it is to remedy them after they occur. Be aware of, and use, cultural practices that maintain and promote tree vigor. Match tree species to the proper site. Assure sufficient water, nutrients, space, and sunlight. Avoid accidental injuries such as cuts, bruises, and broken limbs. Use practices that favor natural controls such as birds and other predators, parasites, and insect pathogens. Practices such as "pick-up and destroy" and "prune out and destroy" can help reduce hibernating forms and inoculum reservoirs. When all else fails, chemical controls may become necessary.

This booklet will help nurserymen, forest woodland managers, pest control operators, and homeowners to identify and control pest problems on oaks. The major insect and disease pests of oaks in the South are emphasized. Descriptions and illustrations of the pests and their damage are provided to aid in identification. Brief notes are given on biology and control to aid in predicting damage and making control decisions. A list of chemical controls is subject to change, as certain compounds are banned and new materials approved. Thus, the chemical control section can be removed (tear sheet) and discarded when outdated. For further information on pesticides, contact your State Forester, county agent, or the nearest office of State and Private Forestry, USDA Forest Service