LONCHOCARPUS, DERRIS, AND PYRETHRUM CULTIVATION 19 
abundant applications of fertilizer and water, with some reduction 
of light, stored, on a percentage basis, 3.9 times as much rotenone in 
their roots as plants that were retarded. 
Unpublished data, obtained by Jones, White, and Pagan at the 
Puerto Rico Agricultural Experiment Station, show that although 
rotenone percentage does not always increase with age, and may 
even decrease, the total amount of rotenone per acre may increase 
up to an age of 36 months. This work indicates that the economical 
age of harvest might be extended beyond the present recommended 
range of 18 to 27 months, providing a reasonable increase in total 
rotenone continues and as long as the percentage remains at or above 
the commercially preferred 5 percent. 
CULTIVATION IN PUERTO RICO 
Although the rural laborer’s wage in Puerto Rico makes derris 
erowing unprofitable on that island, research workers at the United 
States Department of Agriculture’s Puerto Rico Experiment Station 
at Mayagiiez have conducted important studies on cultural tech- 
niques, which might be of use to planters in other countries. 
Nursery 
Moore’s (25) studies at the Puerto Rico Experiment Station re- 
sulted in the recommendation that 12-inch cuttings of mature stems 
be used as propagating material. These are rooted in unshaded 
nursery beds consisting of ridges 8 inches high by 18 inches wide 
and spaced 4 feet from center to center. The ridges are opened 
transversely with a hoe, and the cuttings placed at an angle of about 
45° from the horizontal. All but the tips of the cuttings are covered 
with soil (fig. 12). Moore prefers friable clay or clay loam soils for 
nursery beds, since they erode less easily. (In the Far East sandy 
soils are preferred.) Moore also suggests a minimum of 6 weeks and 
preferably 3 months in the rooting nurseries. 
Working with indolebutyric acid, Cooper (2) found that leafy 
ereenwood cuttings of derris make excellent propagating material 
when butt ends are treated with 50 percent ethyl-alcohol solutions 
containing 5 mg./ml. of this root stimulator and then placed in closed 
sash-covered frames for 3 weeks before transplanting to field nur- 
series. When there is a limited amount of propagating material of, 
for example, special high-rotenone-yielding clones, this method can 
ue la to take advantage of green vinewood which would otherwise 
e lost. 
Transplanting 
This operation should take place when rains are sufficiently frequent 
to keep the cuttings from drying out before they become established. 
When they are ready for transplanting, the viny tops which develop 
in the nursery beds are trimmed back with machetes to stumps about 
6 inches long. Then the cuttings are lifted from the beds for transfer 
to the field, which should be weed-free and in good tilth as the result 
of previous plowing and disking. At the Puerto Rico Experiment 
Station, Moore used plows to open 4-inch-deep planting furrows 
spaced 3 feet apart. Every 2 feet a rooted cutting was laid flat in 
the bottom of the furrows with the vine stump protruding above the 
