DESCRIPTION OF PLATES. 



Plate I. Normal and abnormal growths of bamboo : A, normal ; B, abnormal. 

 A striking example of a witches'-broom formation. These were not col- 

 lected at the same time, but are presumably the same species. 



Plate II. The effect of formaldehyde gas on cultures of Thielaviopsis resulting 

 from the use of 800 c. c. of formalin per 1.000 cubic feet of air space. A, 

 Check ; B, G, and D, transfers from cultures subjected for 15, 30, and 60 

 minutes, respectively, showing the gradation in the growth one hundred and 

 ninety hours after fumigation. 



Plate III. The effect of formaldehyde gas on cultures of Thielaviopsis result- 

 ing from the use of 900 c. c. of formalin per 1,000 cubie feet of air space. 

 A, Check ; B, C, and D, transfers from cultures subjected for 15, 30, and 60 

 minutes, respectively, showing the gradation in the growth one hundred and 

 ninety hours after fumigation. 



Plate IV. Fumigated and nonfumigated pineapples. A, Check; B, fruit inocu- 

 lated and fumigated, and C, fruit inoculated and nonfumigated. The fruit 

 was inoculated by deep incisions. Formalin was used in the proportion of 

 1,200 c. c. per 1,000 cubic feet of air space. Photograph was taken seventy- 

 two hours after fumigation. 



Plate V. Cultures from inoculated pineapples before and after the fumigation 

 of the fruit. A and B, Transfers before fumigation; G and D, transfers 

 after fumigation. The photograph was taken one hundred and twenty- 

 eight hours after fumigation with 1,250 c. c. of formalin per 1.000 cubic 

 feet of air space, showing the negative growth in the transfers from 

 fumigated fruit. 



Plate VI. Cultures from inoculated pineapples before and after the fumigation 

 of the fruit. A and B, Transfers before fumigation ; G and D, transfers 

 after fumigation. Photograph was taken one hundred and twenty-eight 

 hours after fumigation with 1,300 c. c. of formalin per 1,000 cubic feet of 

 air space, showing the negative growth in the transfers from fumigated 

 fruit. 



Plate VII. Fumigated and nonfumigated pineapples. A, Check; B, sprayed 

 with spores and fumigated, and C, sprayed with spores and nonfumigated. 

 The photograph was taken seventy-two hours after fumigation with 1,200 

 c. c. of formalin per 1,000 cubic feet of air space. G shows the fungus 

 developing from numerous centers of infection. 



Plate VIII. Artificially inoculated pineapples. Fig. 1. — Fruit inoculated by 

 incision method. The fruit was not fumigated in this case and the fungus 

 developed abundantly in forty-eight hours. Fig. 2. — Fruit sprayed with 

 spores and not subjected to fumigation. Numerous centers of infection are 

 visible. 

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