E-665 
thiited States Department of A^lculturi 
Aiprieultural Beteareh Adninittratlon 
Bureau of fiitonolofir and Plant Qparantlne 
I THS PLANT AS A SOTJBCS 07 INSBCTICIDX8 
\ A BX7IXV 07 tES LITZRATDES 
i , 
Igr V* X* Mclndoo, Dlvltlon of Inteetlclde Inreitig^tlont 
\ Interest in the use of the eastor-hean plant ( Blclnus conmunis 
L.) for the control of insects has heen stiorolated in the past few 
years popular articles declaring that crops could he protected hy 
means of border or strip plantings of this plant, and also the 
recent derelopnent of a hew spray material extracted from it# leares. 
In order to leam the hasis for these reports and to determine 
whether it would he worth %diile to do more work on the castor-hean 
plant as a source of insecticides, a search of the literature was nutde* 
The information obtained is briefly re-riewed in the following notes« 
Insects Reputed to Be AffeetM. 
grasshoppers , —In New South Vales it was suggested that castor- 
beans be sovn in small patches near the breeding ground of grass- 
hoppers for the purpose of destroying this pest. This plant was re- 
ported to be fatal to grasshoppers* In fact, it was said that "the 
locusts will fairly bury up the young plants, so thidcly will the dead 
accumulate underneath th«B«*— Anonymous (2)* 
In 7ictoria, Australia, the planting of Ricinus communis on the 
borders of fields was considered an efficacious means of controlling 
locusts.— Haras (36. p. 109)* 
Swarms of immature grasshoppers , S<Aistoceroa gregaria (7orsk. ) , 
were obserred in Senegal, Africa, damaging various plants, but Ricinus 
was not attacked.— Troehain (U7. p. 356). 
The following statements cure from a newspaper clipping (Jme 26, 
193s) ^ Roger 0. Staith, of Manhattan, Cans. "Castor-bean plant 
may prore nemesis of hopper. It may be solution to pest problem. 
Certain varieties are highly toxic to grasshoppers." Such was the 
opinion of Leo M. Christensen and Harry Miller. In I937 these men 
discoTered by accident that certain varieties of the castor-bean plant 
are highly toxic to grasshoppers and other insects. The discovery came 
about when the two scientists, who are experts in the field of chemursr, 
were sti\dying castor-beans as a commercial vegetable and cellulose crop. 
In 193s they learned more details concerning the toxic effect of castor- 
