﻿2 BULLETIN 1364, U. S. DEPARTMENT OF AGEICULTUEE 



or indirectly in the growing of crops, including particularly fruit 

 growers, entomologists, and plant pathologists. Of course the bee- 

 keeper does not want his bees poisoned, chiefly Hbecause as a result 

 his honey crop is reduced; but this loss is only secondary in com- 

 parison with the loss from lack of cross-pollination of flowers. In 

 pollination the beekeeper^ the fruit grower, and in fact everyone 

 is benefited by honeybees. For several years evidence has been 

 accumulating to prove beyond doubt that bees are extremely im- 

 portant as agents of pollination, and in fact should be protected 

 and raised if only for this purpose. The honey they produce may 

 be left for separate consideration. 



The investigation here reported was begun in the spring of 1914 

 at the suggestion of Dr. A. L. Quaintance, in charge of fruit insect 

 investigations, and was originally planned to determine the effect 

 on honeybees of spraying fruit trees in full bloom. After one 

 season's work in two States, it was ascertained that spraying at 

 this stage under favorable conditions was detrimental to bees, and 

 these results suggested that sprajdng even at the customary time, 

 when at least 90 per cent of the petals have fallen, might be slightly 

 injurious to them. This idea is in accord with the one which bee- 

 keepers often express by claiming theoretically that spraying fruit 

 trees at any time is injurious to bees, the degrees of damage done 

 depending on the time and on other conditions. Entomologists, 

 however, do not recommend spraying orchards in full bloom (1) 

 because the codling moth can be as well controlled by spraying when 

 90 per cent of the petals have fallen and (2) because sj^raying when 

 the trees are in full bloom is injurious to insect pollinators. 



After three seasons' work on this problem, in four States and five 

 localities, it was determined that spraying at the customary time 

 under nearly ideal conditions was not injurious to bees; but it will 

 be noted that these nearly ideal conditions seldom occur. 



Other projects were discussed and partially planned, but only one 

 of these was finally investigated. The subject of the poisoning of 

 bees by sprayed or dusted cover crops, often grown in orchards, is 

 vitally important to beekeepers, but it seems that fruit growers 

 pay little attention to this phase of the general subject of poisoning 

 bees. This subject Avas only incidentally touched upon, as reported 

 under the experiments performed at Roswell, N. Mex. 



During the past few years it has become common to dust calcium 

 arsenate or lead arsenate upon a large variety of plants, including 

 fruit trees, flowering shrubs, fields of cotton, and even forest trees. 

 This general practice of spreading poisons keeps the beekeepers 

 constantly excited, although probably without warrant, and they 

 have a feeling that their business may be doomed any day. Further- 

 more, it is now common in certain localities of the South to mix 

 calcium arsenate with molasses and then to spray or to daub this 

 poisonous mixture on cotton plants for the purpose of attracting 

 and poisoning the boll weevil. As a part of this general project, 

 the senior writer in July and August, 1922, carried on experiments 

 at Tallulah, La., to determine the effects on honeybees of dusting- 

 cotton plants with calcium arsenate, and also of treating these 

 plants with poisoned sweet mixtures. A summary of their results 

 {10) has already been published, and, since there is no immediate 



