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25 netric tons of cube or tinbo were shipped fmi. Para during 1934. The 
average export price on tiiis material in ^ 934 was about $480 per netric 
ton, f.o.b., Delen. Several pulverizer and extraction plants are in oper- 
ation in the states of Anazonas and Para, The average contort of rotcnone 
in the Brazilian tinbo is about 5.5 to 6 percent. Carbon tetrachloride is 
largely used for the extraction of rotenone from tinbo, and the Brazilian 
G-overnnont has aided several in the importation of this solvent when used 
for the extraction of rotenonog 
An anonymous (5) writer in 1937 referred to the interest in rotenone 
< plants in Brazil and the efforts of the government to foster the growing of 
tinbo and the extraction of rotenone. Only powdered root containing anin- 
inun of 3.5 percent rotenone can be exported from the state of ^ara. 
British Guiana . — The British Guiana Department of Agriculture (48) in 
its annual report for 1932 reported that haiari grew better in the open than 
under shade. The white haiari grows more vigorously than the blacl:. The 
growth of both types is better on sandy soils than en laterite. "aiari is 
easily established from cuttings put in the ground after clearing the bush 
and needs little attention beyond periodic weeding. In its 1933 annual re- 
port (49) tnis department recorded that in only one sample of haiari, a 
nature root iron the forest, did the rotenone content approach 3 percent. 
The root system of the haiaris is not large and that of the black variety 
is very poor. Experiments with plants of insecticidal value, black and white 
haiari (L one ho car pu s spp , ) have been continued at the Hosororo Experiment 
Station, The blacl: and white haiaris planted in the open at the Wauna sub- 
station are making "better growth than those planted in the shaded areas. In 
its 1934 report ^50) the Eritish Guiana Department of Agriculture again re- 
ported that the haiaris grow more vigorously in the open tnan under shade. 
The black haiari, which under similar conditions had not at first appeared 
so vigorous as the white variety, was now almost equal tc it in rate of 
growth. In the North West District of 3ritish Guiana no cultivation of 
poison plants was carried out during 1934, the plants being allowed to -row 
wild* 
Martyn and Folic tt- Smith (271) in 19LS6 reported on the growing of 
Lonchocarpus in British Guiana. Since 1929 the Department of Agriculture 
has had. the "black" .and "white" haiaris of the North West District under 
cultivation at their experiment stations in that district. At Hosororo 
the plants were grown both under shade and in the open en l.atcrite soil, 
and at the Wauna substation under similar conditions cf light and shade but 
on a sandy soil. The shaded areas in both cases consisted of secondary 
forest in which the undergrowth and smaller trees had been cut down. The 
plants grow easily from stem cuttings, and it has become appearent that growth 
on the sandy soil is more vigorous than on laterite, and that much better 
growth is made in the open. At first the black haiari grew rather more 
slowly than the white, but this difference v/as not noticeable after the first 
three years or so. The plants in the open were assisted by periodic v/ecding 
for the first 3 to 4 years of- their development, after which they maintained 
themselves. The value of limestone as a fertilizer for the haiaris is being 
studied, .White haiari roots aged 7 years were analyzed for rotenone with 
the following results; 
