Page:Report of the Puerto Rico Experiment Station (IA CAT31294391015).pdf/9

 cultural Relations who supervised the growing and harvesting of these plants in Nicaragua. Two of these varieties were identical with Changi No. 3 MG and Sarawak Creeping grown at this station and used to establish the foregoing regression equations. Rotenone content and toxicity of these samples were calculated from these equations and the actual total chloroform extractive values. The calculated rotenone percentage was 6.1 compared with 6.0 for the Changi No. 3 MG variety and 2.7 compared with 2.5 for the Sarawak Creeping. The toxicity values were in similar agreement. The calculated toxicity value, 12.4 percent, agreed closely with the actual assay value, 12.1 percent, for the Changi No. 3 MG. The calculated value for the Sarawak Creeping was 7.1 percent compared with the assay of 6.8.

These data indicate that there is a constant relationship of the toxic constituents within a given variety of Derris elliptica grown at two different locations. This relationship is probably due to generic factors and therefore should be constant for any given variety regardless of location.

C. Pagán and R. H. Hageman

At the request of the Office of Foreign Agricultural Relations, a complete chemical and biological analysis was made of three samples of Lonchocarpus nicou (Aubl.) DC. and two of L. urucu Killip & Smith. L. urucu is far more vigorous, has dark-colored foliage, and has a much heavier root system than does L. nicou. However, L. nicou was superior to L. urucu with respect to chemical values and toxicity. L. nicou had 5.3 percent rotenone, 14.4 percent red-color value, 16.3 percent total chloroform extractives, and 9.1 percent rotenone equivalent. The corresponding values for L. urucu were 1.3, 2.6, 3.2, and 1.9, respectively.

H. F. Winters

Field planting of several Cinchona species was started in the western part of Toro Negro Forest in 1943. In subsequent years additional plantings were made, which included the more important cultivated strains of Cinchona. A summary of plantings to date shows that, in general, a low rate of survival indicates a high incidence of susceptiility in the strain to a root-rot disease presumably caused by a species of Phytophthora. However, some loss of plants has been due to wind damage.

Growth of the different strains varied from almost none, to extreme vigor. In the plot of 5-year old Cinchona ledgeriana Moens, from Maricao tree No. 24, many of the trees stand 15 feet tall and have a trunk diameter of 3 inches. Although this strain has performed better than many of the other strains, it is not entirely resistant to the disease. Survival has also varied in the 30 strains of Cinchona brought from the Philippine Islands by Col. Arthur F. Fischer. In this group the strains showing hybrid characters have made the most vigorous growth.

H. F. Winters

Damping-off causes considerable death of plants in Cinchona seedbeds. An experiment was conducted to compare the effects of media 860108—49—2