- Kowal, R. J. 1949b. Control of wood-boring insects in green logs and lumber. Forest Products Research Society, Proceedings 3469-479.
- Kowal, R. J. 1949a. Benzene hexachloride for the control of insects attacking green logs and lumber. Down to Earth 512-13.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1959. Key to Southern forest tree insects—based on damage symptoms . Forest Farmer, Manual Edition 19:106-107.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1964. Key to southern forest tree insects—based on damage symptoms . Forest Farmer, Manual Edition 23:32-40.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1966. Key to forest tree insects of the South . Forest Farmer, Manual Edition 25:80-84.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1968. Key to forest tree insects of the South . Forest Farmer, Manual Edition 27:40-43.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1971. Key to southern forest tree insects of the South . Forest Farmer, Manual Edition 30:96-102.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1972. Key to forest tree insects of the South . Forest Farmer, Manual Edition 31:31-36.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1975. Key to damage of southern forest trees by insects . Forest Farmer 39:114-119.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1977. Key to damage of southern forest trees by insects . Forest Products Dir. 1977:144-149.
- Ebel, B. H., E. P. Merkel, and R. J. Kowal. 1980. Insect damage: key to identification of southern forest pests . Forest Farmer, Manual Edition, 23rd Edition, 39:101-106.
- Johnston, H. R., and R. J. Kowal. 1949. New insecticides for the prevention of attack by ambrosia beetles on logs and lumber . Southern Lumberman 179:183-188.
- Kowal, R. J. 1948. Prevention of damage to logs and lumber by ambrosia beetles. United States Department of Agriculture, Bureau of Entomology and Plant Quarantine, Forest Insect Investigations.
- Kowal, R. J. 1949c. Prevention of damage to logs and lumber by ambrosia beetles. United States Department of Agriculture, Bureau of Entomology and Plant Quarantine, Division of Forest Insect Investigation. 2 p.
- Kowal, R. J. 1950a. BHC protects logs and lumber from pin hole borers . Journal of Forestry 48:333.
- Kowal, R. J. 1950b. Insects commonly attacking forest trees and unseasoned timber in the southern states . Forest Farmer 9:28-31.
- Kowal, R. J. 1953. The relationship of forest entomology to timber practices in the South . Association of Southern Agricultural Workers, Proceedings 50:105-106.
- Kowal, R. J. 1955a. Insects commonly attacking forest trees and products in the South. Edition 3 [Scolytidae, p. 22-29]. Forest Farmer, Manual Edition (?).
- Kowal, R. J. 1955b. Ips beetles are killing pines: what shall we do about it? United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Research Note 81. 2 p.
- Kowal, R. J. 1955c. Some outstanding problems in forest entomology in the South [abstract] . Association of Southern Agricultural Workers, Proceedings 52:100.
- Kowal, R. J. 1955d. Where we stand in our fight against forest insects . Forest Farmer 14:4-6.
- Kowal, R. J. 1956a. Forest entomology in southern United States. United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 1 November 1956. 10 p.
- Kowal, R. J. 1956b. Forest insects . Forest Farmer, Manual Edition 16:169.
- Kowal, R. J. 1956c. Progress and needs in forest insect research, survey, and control in the Southeast . Association of Southern Agricultural Workers, Proceedings 53:129.
- Kowal, R. J. 1956d. The southern pine beetle in Tennessee . Keep Tennessee Green News 1956:3.
- Kowal, R. J. 1957a. Insects commonly attacking forest trees and products in the South . Forest Farmer, Manual Edition 17:30-36.
- Kowal, R. J. 1957b. Increasing importance of insects in forest management in the South. Virginia Tech. Forester 9:19-22.
- Kowal, R. J. 1957c. Progress in southern forestry: forest insects . Forest Farmer, Manual Edition 17:10.
- Kowal, R. J. 1957d. Relation of forest management to the forest insect problem in the South . Society of American Foresters, Proceedings 1956:175-181.
- Kowal, R. J. 1957e. We can check the silent killers . Forest Farmer 176, 7, 12, 18.
- Kowal, R. J. 1958a. Forest entomology in southern United States . International Congress of Entomology, Proceedings 10:399-406.
- Kowal, R. J. 1958b. The present state of forest insects . Unit (Atlanta) 74:24-25.
- Kowal, R. J. 1959a. Meeting the problem of tree killing insects. Forest Farmer, Manual Edition 17(7):38-46 (1958).
- Kowal, R. J. 1959b. Shade tree insects in the South: their increasing importance and control . National Shade Tree Conference, Proceedings 34:159-171.
- Kowal, R. J. 1960a. Insects commonly attacking forest trees and products in the South . Forest Farmer, Manual Edition 19:100-105.
- Kowal, R. J. 1960b. Southern pine beetle. United States Department of Agriculture, Forest Service, Forest Pest Leaflet 49. 7 p.
- Kowal, R. J. 1960c. The problem of tree killing insects and how to meet it . Forest Farmer, Manual Edition 19:98-100.
- Kowal, R. J. 1961a. Common bark beetles found in the southern states . Forestry Bulletin 57:1-2.
- Kowal, R. J. 1961b. Control of insects affecting shade trees and small woodlands . Is there a market for the PCO in this field? Pest Control 299-10, 12-13, 16, 77-78, 80.
- Kowal, R. J. 1961c. The future of insect control . Forest Farmer, Manual Edition 21:17.
- Kowal, R. J. 1961d. The problem of tree killing insects—and how to meet it . Forest Farmer, Manual Edition 20:70-72.
- Kowal, R. J. 1962. The problem of tree killing insects and how to meet it . Forest Farmer, Manual Edition 21:64-66.
- Kowal, R. J. 1964. Forest insects: the problem and how to meet it . Forest Farmer, Manual Edition 23:25-26.
- Kowal, R. J., and J. S. Boyce. 1955. Diseases and insects . Forest Farmer, Manual Edition 1955:172-173.
- Kowal, R. J., and J. F. Coyne. 1951. The black turpentine beetle can kill trees . AT-FA Journal 137, 14-15.
- Kowal, R. J., and J. F. Coyne. 1952. Forest insect problems in the South . Association of Southern Agricultural Workers, Proceedings 49:91.
- Kowal, R. J., and B. H. Ebel. 1971. Insects attacking forest trees in the South . Forest Farmer, Manual Edition 30:89-95.
- Kowal, R. J., and B. H. Ebel. 1977. Insects attacking forest trees in the South . Forest Products Directory 1977:137-143.
- Kowal, R. J., and H. Rossoll. 1958. Beetles in your pines? How good cutting practices and management stop beetles from killing your timber. United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Asheville, North Carolina. 29 p.
- McCambridge, W. F., and R. J. Kowal. 1957. Forest insect conditions in the Southeast during 1956. United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Paper 76. 7 p. (processed).
- McCambridge, W. F., W. P. Nagel, and R. J. Kowal. 1958. Forest insect conditions in the Southeast during 1957. United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Paper 93. 10 p.
- Merkel, E. P., and R. J. Kowal. 1956. Forest insect conditions in the Southeast during 1955. United States Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Station Paper 67. 9 p. (Processed).
- Orr, L. W., and R. J. Kowal. 1956. Progress in forest entomology in the South . Journal of Forestry 54:653-656.
- Smith, R. H., and R. J. Kowal. 1968. Attack of the black turpentine beetle on roots of slash pine . Journal of Economic Entomology 61:1430-1432.