Ro ford 209 5 Cynomys ludovicianus September 12, 1955 Denver, Colo. 1938, largest organized county-wide rodent control program to date. CCC crews used. WPA project for no prairie dog control in Weld Co. 1/191,385 A. treated for field rodents. 1939, 1,556,011 acres treated. Cayote-getter tried. Gas cartridges & cyanide flobber used as cleanup. 1941, CCC program discontinued June; this handicapped rodent control. 1942, plague found in prairie dogs in Colo. 1,121,286 acres treated for prairie dogs. (Maynard W. Cummings in charge). 1944, plague in Laramie & Neuerano counties [in Colo.?]. Thallium treated bait stations used for predator control. Supervised prairie dog poisoning 300,715 acres, non-supervised 226,119 acres, in Colo. (brown squirrels about 1/4 these acreages in addition). 1945, supervised 227,364 A. of prairie dogs; non-supervised 208,731 acres. 1946, 1080 used two counties under direction F4WL Research Lab. Sup. p.d. control, 648,882 A.; non-sup., 237,504 A. 1947, 1000 monthly. 1,210,234 acres treated (all-time high)- sup. p.d. 1,114,158 A.; non-sup. 164,210 A. 1948, more 1080 bait stations in most counties. 1948 monthly 1080 by sup- ervised crews. 1948, unsatisfactory cleans of ginnies, gyuri, white-tailed prairie dogs. (One idea to mix grass seed with poison bait; reseed or poison). 1949, supervised p.d. control 671,664 A.; non-sup. 40,418 A. 1950, rodent control in 50 of 63 counties. Good results only on C. lud. 1952, acre- ages loosened; supervised p.d. 189,742 A.; non-sup. 12,777 A. 1952-3, moor grass used, especially SW Colo. where poisoned grain acceptance poor. || Dr. Spencer says when bait not accepted, (canine) change of bait more important than change of poison.