10 BULLETIN 52, V. S. DEPAKTMENT OP AGEICULTURE. 



fruit is set it can be brought through to ripening free from fungous 

 infection by spraying at certain intervals, but that spraying is of 

 little or no value in controUmg the blossom-blight form of the disease 

 and that profitable sets of fruit can be expected only during seasons 

 which are dry at blooming time, unless varieties which are resistant 

 to the disease are developed and cultivated. Spraying every day 

 prevented a set of fruit and spraying every other day did not save 

 sufncient fruit to justify the expense involved. 



There are not sufficient data to make definite and conclusive 

 recommendations as to the frequency with which it will be necessary 

 to spray to get the best results, but it seems probable that the panicles 

 should be sprayed at least every fourth day between the times the buds 

 begin to swell and the flowers begin to open and that after the fruit 

 is set it should be kept covered with Bordeaux mixture during the 

 first 8 to 10 weeks of its development. The fruits are most sus- 

 ceptible to infection just as they are setting. Consequently, it ap- 

 pears that it would be best to make three applications of Bordeaux 

 mixture at weekly intervals, applying the first when about one-half 

 to two-thirds of the blossoms have opened, and following these by 

 a fourth application after a lapse of two weeks and a fifth three weeks 

 later, making five sprayings for the fruit and two, or in some cases 

 three, for the panicles. 



INFLUENCE OF THE WEATHER ON POLLINATION. 



It has been tentatively suggested by Fawcett ^ and by Collins ^ that 

 the blighting of the blossoms, which is so uniformly observed through- 

 out the Tropics whenever the mango is subject to moist, showery 

 weather at blooming time, may be due to lack of pollination. 



It is probable that such conditions interfere with pollination to 

 some extent, but the evidence at hand points strongly to the fact 

 that in Florida, at any rate, the anthracnose fungus is chiefly respon- 

 sible lor this phenomenon. Repeated attempts have been made to 

 germinate the pollen, but without success. The fact that the mango 

 fruits heavily in dry localities indicates that its shy bearing in Florida 

 is due to external conditions rather than to any inherent defect in the 

 plant. 



An exact count was made of the number and types of flowers borne 

 on 10 panicles of a Mulgoba, 10 of a Totafari, and 5 of a seedling 

 mango tree. They were made by going over the flower clusters 

 every day and picking off with a pair of forceps the flowers that had 

 opened, the kind and number bemg recorded. The mango bears 

 two t3rpes of flowers, staminate and perfect, and only one stamen is 

 found in .each flower. 



The 10 Mulgoba panicles bore a total of 7,038 flowers, of which 

 4,119 were staminate and 2,919 perfect. The 10 Totafari panicles 



1 Op. cit. 



