Bacterial Disease of the Squash-hug. 351 



Experiment Jf.. — One of the most successful experiments 

 with the organism of this disease was the result of test- 

 ting- the bacillus found so abundantly and almost pure 

 in one of the early isolation cultures. A young colony 

 direct from a Petri dish was diffused in a small quantity 

 of water, and each of five squash-bugs was thoroughly 

 wet with the infusion. Three of the insects were dead on 

 the morning of the second day, and at the end of two 

 and one half days all were dead. A check lot of bugs 

 used in conjunction with this experiment remained 

 healthy. 



Experiment 5. — About forty squash-bugs were inoculated 

 from diseased insects, the cage being without moisture 

 except that furnished hj the food leaves. The results 

 indicate that the disease took rapid effect, as fifteen 

 bugs were dead at the end of five days. From this time 

 the death rate diminished, but the bugs dropped off 

 gradually until only two or three apparently resistant 

 ones remained. 



In order to compare the effect of pure cultures of vari- 

 ous ages with infusions direct from diseased insects as 

 sources of infection, a series of experiments were made 

 in each of which six bugs were used. When pure cultures 

 were emploj'ed, some of the bacterial growth was diffused 

 in distilled water, and in this the insects were momenta- 

 rily immersed. With the diseased or dead bugs an 

 infusion was likewise prepared by tearing the bodies 

 apart in water. Healthy bugs from two different fields 

 furnished the subjects, and a separate check was used 

 for each lot. All dead insects were removed as soon as 

 observed, in order that the results might follow only 

 from the first infection. 



