4 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
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. They 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 dried in the shade. | 
Several authors (150, 257, 261, S13) 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, the insect powder at Fiume is made from the blooms of a wild 
chrysanthemum (Pyrethrum cinerariefolium 'Treviranus), which 
srows 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 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 
srows best in rocky and barren hills with Jittie 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 1s first har- 
vested 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 powder is that obtained from the ‘‘buds” or the unopened wild 
blooms in the region of Krivosije, Dalmatia. The second quality, 
that from half-opened blooms, comes from Cittavecchia, Dalmatia. 
The third, from the full blooms, is produced in Ragusa, Dalmatia. 
The ‘‘buds” used in making the first-quality powder are very small, 
6 to 8 millimeters in diameter, and look like a large chamomile flower. 
The cultivated plants bear flower heads with a diameter of from 8 to 
10 millimeters, having the rays very close together and covering the 
crown, being again covered by involucral bracts. Powder of the third 
quality is prepared from flower heads with a diameter of from 10 to 
12 millimeters, almost disklike in form, many of them being without 
ray florets. 
After the nature of insect powder became known, the cultivation 
of Pyrethrum was taken up in several countries. Willemot (294) 
describes the growing of Pyrethrum roseum, introduced into France 
about 1856, and Heckel (123) discusses the cultivation of P. cinerarix- 
folium in the botanical garden of Marseilles. Efforts to grow 
C. cinerariefolium on a commercial scalo in southern France have 
been fairly successful (S16, S29). In Switzerland also the growing 
of insect flowers has been encouraged and seems promising (S10, 
S11, 812). 
