4 BULLETIN 52, TJ. S. DEPAKTMEISTT OF AGRICULTURE. 



been natiirallv infected . On March 10 the three panicles sprayed 

 with spores showed mmute dark spots. The control was clean. On 

 March 21 the four panicles were removed from the tree. The control 

 was still clean, while those sprayed with spores were conspicuously 

 marked on the peduncles and pedicels. Those showing disease were 

 placed in a moist chamber, and in two days large quantities of 

 anthracnose spores had oozed out from the infected parts. This 

 experiment was repeated on two other occasions without variation, 

 and the same results were obtained. 



Bessey ^ conducted inoculation experiments with tliis same organ- 

 ism and writes as follows: 



Under Prof. Rolfs's direction, before he severed his connection with the Subtropical 

 Laboratory, inoculation experiments were begun, which have been continued, with 

 some interruption, under my direction since I assumed charge of the laboratory. 

 These have demonstrated that this fungus (Colletotrichum gloeosporioides) is the 

 same one that causes the blossom blight, leaf spot, and fruit rot of the mango and 

 avocado, the tear staining of the mango, and the leaf spots and fruit rots of various 

 other plants. 



SPRAYING EXPERIMENTS IN THE SPRING OF 1912. 



It was hoped to determine two points hj means of these sprajong 

 experiments: (1) Is Bordeaux mixture effective in preventing mfec- 

 tion of the flower clusters and fruits, and (2) how frequently and at 

 what times is it necessary to spray to get the best results ? 



Unfortunately for the success of the work, there are no large groves 

 of mangos in Florida. However, the work was done on as large a 

 scale as was possible, and certain results which will be emphasized 

 in other parts of this paper stand out quite clearly. Bordeaux mix- 

 ture was the only fungicide used, and it was made according to the 

 3-5-50 formula m 1912 and the 4-6-50 formula ^ m 1913. The 

 spraying outfit consisted of a 50-gallon barrel sprayer, half -inch hose, 

 and 9-foot bamboo extension rods equipped Avith double Vermorel 

 nozzles. The spraying was done under a pressure of approximately 

 75 pounds to the square inch. With one exception, noted later, no 

 spray injury was observed at any time, and this is significant, as just 

 such conditions existed as might be expected to induce it, i. e., the 

 weather was moist and showery during the first thi-ee weeks in which 

 the spraying was conducted. 



The experiments were carried on at Mr. Flanders' s place, about 2 

 miles north, and Mr. Roop's place, about 3 miles west, of Miami. 



THE EXPERIMENT IN THE FLANDERS GROVE. 



The mangos on the Flanders place consisted of a double row of the 

 Mulgoba variety, each row containing 31 trees. They were divided 



1 Bessey, E. A. Op. eil. 



* Tliis shows the proportion of copper sulphate (bluestonc), lime, and water u-scd in th(; mixtures. 



