MEANS OF PREVEXTIOX AXD CONTROL I3S3 



INJURIOUS INSECTS AND OTHER IvOWER ANI^IAIvS. 

 1044 - Experiments in Locust Control by Means of Coccobacillus acridiorum means 



in Argentina (i). — Kraus Rudolf, in Centyalblatt fur Bakterioloi,ie, Parasitcnkundc und of prevention 

 Infcktiomkninkheiten, Vol. 45, Xo. 18-25, pp. 594-599. Jena, June 19, 1916. and control 



The writer first gives a description of Coccobacillus Acyidiormn dis- 

 covered by Felix d'Herelle in Mexico in 1909. He then refers to the 

 control experiments conducted by d'H:6rellE himself in Mexico, and finally 

 he mentions the observations made on this bacterium in Colombia, vSouth 

 Africa and Argentina. 



In Argentina, the Ministry of Agriculture has appointed a Commission, 

 of which the Author is a member, the object of which was to repeat the ex- 

 periments of d'Herelle and draw up a detailed report on the results ob- 

 tained. The Commission had at its disposal cultures coming direct from 

 the Pasteur Institute and which, according to bacteriological investigations, 

 corresponded perfectly to the Coccobacillus of d'He;relle. 



D'HiiRELLE described this Coccobacillus as a micro-organism having 

 few typical characters. For that reason the Author thought it necessary 

 to determine in the first place whether in the intestine of locusts there are 

 no micro-organisms resembling the Coccobacillus of d'He;relle. He was able 

 to isolate from the intestine of the healthy insect organisms which are mor- 

 phologicalh' identical with the Coccobacillus, which led him to suppose that 

 this latter is usually present the intestine of the locust. 



For the purpose of successful control of locusts in the open field, a viru- 

 lent culture is required, according to d'H^relle, who says that before 

 beginning the experiment the virulence must be checked to see whether 

 it is sufficiently eft'ective. Unfortunately no criterion of virulence is indi 

 cated. 



He only says that 12 passages through locusts are sufficient to give the 

 cultures the necessary virulence. 



The virulence was determined bj' the writer by means of a normal loop. 

 The culture used first had a virulence of 1/200 loop, and later, after passing 

 through the locusts, a virulence of 1/2000 loop. The virulence of this 

 culture remains unchanged for a long time. The writer not only increased 

 the virulence of the Coccobacillus of d'Herelle, but also found that the same 

 effect may be equall)' well obtained in relation to the micro-organisms iso- 

 lated from the intestine of locusts. 



After checking the virulence the Author made experimental infection 

 with Coccobacillus in the laboratory, giving infected foods to the locusts. 

 Contrary- to the observations of other experimenters, he ascertained that 

 these insects, even in captivit^^ will take fairl)^ large quantities of food. The 

 experiments, however, were negative in result, ev^en when large rations of 

 infected food were given. 



(i) See also B. April 1913, X'o. 750. • (£'/•) 



