4 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE. 
In 1913 not less than 200,000 pounds of insect flowers and stems 
were imported at the port of New York from Europe, and in addition 
large quantities were imported at Baltimore and other ports. In 
1914, Japan (292) alone sent directly to the United States 379,873 
pounds of flowers, and during the fiscal year 1917 (June 30, 1916, to 
July 1, 1917) the total importation was 1,504,000 pounds. During 
the recent Great War, the European supply was almost entirely 
cut off. 
CULTIVATION AND HARVESTING OF INSECT FLOWERS. 
An account (5), written in 1856, describes the Pyrethrum plants 
as growing wild in the Caucasian Mountains at an elevation of from 
4,500 to 6,800 feet above sea level. These plants blossom in June, 
and are harvested on a dry day, when an efficient cutter can collect 
from 30 to 80 pounds a day. The flower heads are usually dried in 
the sun, although they act more powerfully when the drying is done 
in the shade. 
Several authors (150, 257, 261) have described the cultivation of 
insect flowers in Dalmatia. According to a communication, under 
date of November 13, 1915, from Benjamin F. Chase, United States 
consul at Fiume, the insect powder there is made from the 
blooms of a wild chrysanthemum (Pyrethrum cinerariaefolium Trevi- 
ranus) which grows in profusion on the east side of the Adriatic Sea, 
from southern Croatia to Montenegro, on the Dalmatian coast, in 
Herzegovina and Albania. The annual production for all of this 
territory is given at from 150 to 200 metric tons. That exported 
is sent chiefly from Trieste, very little going out from Fiume. 
With the development of the trade in insect powder has come 
a cultivation of the wild variety. The plant grows best in rocky 
and barren hills with little soil, especially in limestone formations. 
Humid or deep soil is not favorable for its growth. Warm and 
dry weather is supposed to be best, not only to develop the wild 
plant but to give it its special insecticidal virtue. The cultivated 
plant does not produce well the first year, but starts the second year, 
and, if well cared for, continues to grow from the same root for 20 
years. It begins to bloom in May, and is first harvested in early 
June. One hectare (2.47 acres) of the cultivated variety yields 
111,100 plants, producing 2,000 kilograms (4,412 pounds) of dry 
blooms. The bloom is in best condition for making the powder if 
cut before opening, or in the "bud." It is cut off just beneath the 
head. After cutting, the blooms are spread on cloths and dried in 
the sun. When thoroughly dry they are ground into a fine powder 
by revolving stones, or by crushers working vertically. The finest 
quality powder is that obtained from the "buds" or the unopened 
wild blooms in the region of Krivosije, Dalmatia. The second 
