LONCHOCARPUS, DERRIS, AND PYRETHRUM CULTIVATION 5 
dedicated tolonchocarpusin some cases ranges from 1,000 to 3,000 acres 
or more. 
In 1942 the Instituto Agronomico do Norte at Belém, Brazil, began 
a systematic study of hundreds of mature individual lonchoc: ‘arpus 
plants of Lonchocarpus urucu, Killip and Smith, and also L. utilis, 
A. C. Smith, which plant explorers had brought to Belém. Chemical 
analyses of samples taken from the roots of these individuals revealed 
a range in rotenone content from 0.9 to 20.1 percent among 148 plants 
of L. utilis which were estimated to be between 3 and 5 years of age. 
Weights of fresh roots harvested from these individuals varied between 
20 and 3 895 grams. At the same time 232 individual L. urucu plants, 
approximately 3 to 5 years of age, were studied inthesame way. Their 
rotenone content ranged from a low of 2.2 to a high of 11.2 percent, 
and fresh-root weights varied between 25 and 6,420 grams. At the 
present time average shipments of commercial root contain from 4 to 
6 percent rotenone. 
ex 
Be 
See 
ricgure 10.—Transferring export bundies of lonchoecarpus roots to the dock 
warehouse; Iquitos, Peru. 
An interesting feature of the Instituto Agronomico do Norte’s work 
is the observation that certain L. urucu strains producing high root 
weight may be more profitable to cultivate than the commonly pre- 
ferred L. utilis, which usually produces a higher rotenone content but 
less root weight during an equal growth period. As technicians of the 
Instituto Agronomico do Norte emphasize, the commercial producer 
should be interested in achieving the highest total of rotenone per acre 
per year. 
Work similar to that being done in Belém was begun by the author 
in 1943, when he was assigned to the Estacién Experimental Agricola 
de Tingo Maria in Peru. Since ZL. utilis, according to Krukoff and 
783559°—48——3 
