AMERICAN BEE JOURNAL. 



Jan. 2, 1902. 



it strang-e that Bordeaux mixture 

 should prevent the germination of the 

 pollen. The Bordeaux mixture holds 

 its position as a leading fungicide, be- 

 cause it prevents the growth of fun- 

 gous spores. The germination of 

 pollen is more nearly analogous to the 

 germination of fungous spores than to 

 the germination of grain cited above. 

 Since the Bordeaux mixture is deadly 

 to one, it may be expected to have a 

 similar effect upon the other. That it 

 does have such an effect is proved by 

 laboratory experiments which formed 

 a part of the investigations previously 

 mentioned. Theordinary combination 

 of Bordeaux mixture with an arsenical 

 poison prevented the growth of pollen 

 in laboratory cultures, as also did even 

 lime alone, while in corresponding cul- 

 tures, in which these substances were 

 not present, the pollen germinated and 

 pollen-tubes grew. Bordeaux mixture 

 alone — 1 to 11 formula — was added to 

 cultures in varying proportions, and 

 the effect was remarkable. With 200 

 parts of it in 10,000 parts of the culture 

 media, the growth of pollen was practic- 

 ally prohibited, for the pollen did not 

 grow except in rare instances ; 100 

 parts in 10,000 in some cultures, but 

 not in all, wholly prevented the ger- 

 mination of the pollen : sometimes 50 

 parts in 10,000 gave a similar result, 

 and even the very slight proportion of 

 2 parts in 10,000 in some cases showed 

 an unmistakably adverse influence on 

 pollen-germination. Since pollen must 

 alight upon the stigmatic surface, and 

 there germinate before fertilization can 

 take place, these results are highly 

 significant to the fruit-grower. 



From the facts which have been pre- 

 sented it is clear that applying the 

 spray mixtures on the open blossoms, 

 instead of assisting directly to set the 

 fruit, may wholly prevent it. 



But some fruit-growers feel sure that 

 spraying in bloom has caused a posi- 

 tive improvement in their apple crop. 

 How can such results be accounted 

 for? One of the worst diseases in New 

 York apple orchards is the scab. Does 

 spraying in bloom give some degree of 

 protection against this disease? It is 

 well known that the amount of dam- 

 age from this disease varies greatly in 

 different seasons. In 1896, for example, 

 the apple crop was remarkably free 

 from injury from the scab, even on 

 trees which had never been sprayed. 

 In 1898, on the contrary, in Western 

 New York, the scab became virulent 

 so early in the season that in many 

 cases it killed a considerable portion 

 of the blossoms, and later continued 

 the destruction on the immature fruit. 



The apple-blossoms grow in clusters 

 having perhaps from 5 to 7 in the clus- 

 ter, although the number may vary 

 considerably. They do not all open at 

 the same time. The one in the center 

 opens first and is normally the strong- 

 est and forms the largest ifruit. Those 

 immediately around the central one 

 open next in order, and lastly the out- 

 side blossoms of the cluster open. The 

 whole process generally takes from a 

 week to 10 days in this part of the 

 country. It varies with weather con- 

 ditions. When the last ones are open- 

 ing, the central blossom has usually 

 passed out of bloom. Not only is there 

 this difference in the time when the 

 different flowers in a cluster open, but 

 also in the same way tree-clusters which 

 are less exposed to the heat of the sun 



are correspondingly retarded in bloom- 

 ing. Consequently, all of the clusters 

 on a tree do not begin blooming at the 

 same time. It appears, therefore, that 

 there is no one time when all the apple- 

 blossoms on a tree are open. Of those 

 which are open, some are sure to escape 

 being hit in the center when thespray- 

 1 ing is done in an ordinary way. 



When there is an abundance of 

 bloom, and when the apple-scab be- 

 comes destructive as early in the sea- 

 son as the time when the blossoms are 

 opening — as was the case in 1898 — 

 spraying once in bloom might not de- 

 stroy enough of the blossoms to reduce 

 the crop of fruit seriously and yet give 

 a degree of protection against the scab 

 which would result in improvement in 

 the amount and character of the crop ; 

 but it has not yet been demonstrated 

 by rigid experiments that even in such 

 a season spraying in bloom gives supe- 

 rior results to those which may be ob- 

 tained by spraying just before and 

 just after the blooming season. In 

 order to get conclusive evidence on this 

 point, it will be necessarj- to continue 

 the experiments till a season arrives 

 when the conditions are somewhat 

 similar to those which obtained in 

 Western New York in 1898. 



Does spraying in bloom ever bring 

 about an improvement in the crop by 

 thinning the fruit ? 



In the experiments reported in the 

 bulletin already cited, it was found 

 that apple-blossoms which were treated 

 with the spray — the ordinary combina- 

 tion of Bordeaux mixture and an arsen- 

 ical poison — in the early part of the 

 blooming season, generally failed to 

 set fruit. Blossoms whicii had been 

 open several days before they were hit 

 by the spray seemed to have reached 

 a stage where such treatment did not 

 interfere with the setting of the fruit. 

 Some results which are apparently con- 

 flicting, may be reconciled by a clear 

 understanding of this point. It appears 

 that there is a difference between the 

 older blossoms and the newer ones as 

 to their susceptibility to injury from 

 spray mixtures. 



Experiments were also made in which 

 portions of trees were sprayed repeat- 

 edly during the blooming season, thus 

 hitting the new blossoms as they open 

 from day to day. As a consequence, 

 scarcely any blossoms set fruit, nearly 

 all being destroyed by the treatment. 

 One spraying, if well done, may be 

 expected to destroy a large portion of 

 the freshly-opened blossoms, and, thus 

 thin the fruit. Such a result was in 

 fact obtained in some of the experi- 

 ments with apples in 1900, and with 

 pears in 1901. In case there is a light 

 bloom, it seems that spraying at a 

 time when most of the blossoms are 

 freshly opened, may cause the loss of 

 a considerable portion of the crop. 

 Some fruit-growers who have tried it 

 have become convinced that spraying 

 under such conditions has caused them 

 very serious loss. 



In the experiments in which spray- 

 ing in bloom has thinned the fruit, 

 the amount of marketable fruit has not 

 always decreased. Such results are 

 similar to those obtained where 'the 

 fruit has been thinned by hand. This 

 suggests the practical question, 

 whether the process of spraying plants 

 in bloom may be used as an economical 

 method of thinning the fruit. Our ex- 

 periments on this point have not been 



carried far enough to give conclusive 

 results. 



In our investigations we have tried 

 to find out what effect the application 

 of the ordinary spray mixtures to open 

 blossoms has upon the blossoms and 

 upon the crop of fruit. There is an- 

 other phase of the subject which inter- 

 ests the fruit-grower, and that is the 

 extent to which bees and other insects 

 are needed for cross-pollination in 

 order to secure a good setting of fruit. 

 It has been proven that with some va- 

 rieties cross-pollination must occur be- 

 fore any fruit can be formed. Others 

 are fully capable of setting fruit with- 

 out cross-pollination. Between these 

 two extremes are found many imper- 

 fectly self-sterile varieties, among 

 which are all gradations between self- 

 sterility and self-fertility, with corres- 

 ponding independence of or depen- 

 dence upon cross-pollination for the 

 setting of fruit. Even some varieties 

 which are classed as self-fertile, may 

 produce better fruit when cross-polli- 

 nated than when self-pollinated. 



Pollen is naturally distributed from 

 one blossom to another by the agency 

 of either winds or insects. Some kinds 

 of pollen are easily distributed by 

 winds ; others are not adapted to wind- 

 distribution, but are easily carried by 

 insects. Apple-pollen belongs to this- 

 latter class. Whether or not the fruit- 

 grower may secure better crops when 

 insects aid in distributing the pollen, 

 must be determined by learning the 

 needs in this direction for each particu- 

 lar variety of fruit which he grows. In 

 case he is growing self-sterile or im- 

 perfectly self-fertile varieties having 

 pollen not readily distributed by winds, 

 the poisoning of bees and other insects 

 which visit the blossoms would work 

 him injury. He then would have a 

 common interest with the bee-keeper 

 in preserving the lives of the insect 

 visitors of the flowers. 



A considerable amount of work has 

 been done for the purpose of determin- 

 ing which ones among our cultivated 

 varieties are self-fertile, and which are 

 imperfectly self-fertile or self-sterile. 

 At some experiment stations further 

 investigations on this subject are in 

 progress. Much yet remains to be 

 done, however, in order that full and 

 satisfactory information on this im- 

 portant point may be available to the 

 fruit-grower. 



Another question which is worthy of 

 attention in relation to the subject of 

 spraying in bloom is the eft'ect of fungi- 

 cides upon bees. We have seen that if 

 spraying in bloom results in an im- 

 provement of the crop of apples, such 

 improvement may come in part from 

 protection against the attacks of the 

 scab fungus, and in part from thinning 

 the fruit. Neither Paris green nor 

 any other recognized insect poison is 

 needed to secure these results. They 

 may be obtained by using Bordeaux 

 mixture alone. It is desirable, there- 

 fore, to know whether there is any dan- 

 ger of poisoning bees by spraying 

 blossoms with fungicides alone. It is 

 worthy of remark in this connection, 

 that in all of the extensive use of Bor- 

 deaux mixture it has not )'et been 

 known to poison insects. Finally, from 

 what has been said, it appears that the 

 desirability of spraying in bloom is a 

 subject concerning which more infor- 

 mation is needed in order to reach a 

 decision which may be accepted by all 



