664 



AMERICAN BEE JOURNAL. 



Oct. 16, 1902. 



hopeful field is the field that is worked properly : and may 

 God give us strength and knowledge to do that work aright. 



Emerson Tavlok Abbott. 

 (Contianed next week.) 



\ Contributed Articles. 



Bees and Bacteria— The Spread of Blight. 



BV PKOF. A. J. COOK. 



OF course all bee-keepers are interested in plants. Plants 

 are so important to their success that even from a finan- 

 cial point of view they must take a deep interest in 

 flowers and the plants that bear them. I hope and believe 

 that with most bee-keepers the interest does not stop here. 

 They know how valuable plants are to others and the feel- 

 ing of kinship to all about us makes us look with interest 

 "on whatever touches others' welfare. I believe also that 

 there is almost always an a-sthetic influence that is perhaps 

 dearer than all else. Dr. Miller loves and cherishes his 

 roses, and who shall say that their ministration to him is 

 not of a kind most blessed ? I need not make any apology, 

 then, if this article, which is the substance of a talk given 

 at a late Farmers' Institute, is strongest on the plant side. 

 Prof. Waite, of the Department of Agriculture— the 

 same who did such admirable work proving that bees were 

 a necessity in the orchard — has now done equally valuable 

 work in showing that our bees also are chief agents in 

 spreading pear-blight. Prof. Waite has proved this beyond 

 any question. He shows that the micro-organisms which 

 cause pear-blight can only live in a liquid or semi-liquid 

 medium. They therefore reach only to the outside of the 

 plant when carried by some secretion or exudation of the 

 same. The bacteriologist has only to visit the plant with a 

 pin-prick, and then insert the same pin into another plant 

 to carry the disease. The tip of the stigma bears the sticky 

 secretion whose natural function is to catch and hold the 

 pollen. This liquid, or semi-liquid, also domiciles the 

 microbes. The bee in quest of nectar touches the stigma 

 and bears away some of the liquid with the microbes, as it 

 does also the pollen -grains. It then hies away to other 

 blossoms, possibly on other trees. Here it leaves not only 

 the pollen but also some of the bacteria. Thus the inocula- 

 tion is as certain as in case of the pin-prick. 



Again, the tender buds are protected by the thin film of 

 liquid resin, which also attracts the bee, as it is here that it 

 gets its propolis or bee-glue. Without doubt the microbes 

 are also in this semi-liquid secretion, and as the bee tlies to 

 other buds for more of the resinous secretion, the inocula- 

 tion is again performed, and so we understand how pear- 

 blight spreads in the nursery rows and how young trees 

 which have never yet blossomed may die of the blight. 



In California, we have another tree which is victimized 

 by what Prof. Pierce, one of our best vegetable pathologists, 

 has determined to be this same germ of pear-blight. The 

 loquat we regard as one of our most desirable fruits, and 

 thus we are as interested in preserving this as our pear- 

 trees. The loquats about us have generally died. The 

 loquat is an evergreen, and is really one of our very beauti- 

 ful trees. It has a strange fashion of blossoming in mid- 

 winter, and so gives us fruit in April — a time when fruit, 

 from its scarcity, is very much appreciated. 



HOW TO DIAGNOSE BLIGHT. 



When the leaves of a tree wither, and we suspect that 

 some blight or microbe is robbing it of vitality, or may be 

 life itself, we should first examine the root and see if gopher, 

 squirrel, insect or lack of, or too much, water have not dis- 

 abled these most important parts of the plant. Without the 

 roots, the plant cannot receive the needed water and min- 

 eral elements. Without these the plant will soon be sapless, 

 and the leaves must wither and die. In case the roots are 

 all right we should examine for insects on the leaves them- 

 selves, or possibly borers working inside the twigs. Many 

 leaf-eating insects feed only on the chlorophyll layers of 

 the leaves, and thus, while they do not take all the leaves, 

 they do rob them of their working part. The leaves, then. 

 of course, are gray and worthless, and suggest blight. The 

 pear-slug and the canker-worms, which destroy apples, other 



fruit trees, and elms, are of this kind. What observer has 

 not noticed dead twigs from the presence and attack of 

 twig-borers ? It may be the roots are all right, that no in- 

 sects are preying upon the plant above ground, and yet the 

 plants fall down because of lack of nourishment in the soil. 

 In such case we should apply nitrate of soda, and will be 

 glad to see our plants immediately revive. If such is not 

 the case, we are then sure that the trouble is not from lack 

 of soil-fertility, and we may pretty surely ascribe the dam- 

 age to the insidious microbe. 



WHAT SHALI, WE DO ABOUT IT ? 



The most potent fungicide, or bacteriacide, yet discov- 

 ered is the Bordeaux mixture, which consists of water hold- 

 ing in solution lime and copper sulphate. The formula I 

 usually give is one easy to remember : 4-4-45. This is easily 

 made as follows : 



Four pounds of fresh quick-lime are slaked, put in a 

 bag and hung in enough water to dissolve it. The copper 

 sulphate is dissolved in the same way in other water. When 

 dissolved they are placed together and enough water added 

 to make forty-five gallons. This is a quick cure for many 

 blights. It does not, however, prove effective against pear- 

 blight. We can easily see why. The germs remain inside, 

 almost entirely, and so are not reached by the liquid. 



The second remedy for blight is the only one, which, so 

 far as we now know, will aid us in combating this terrible 

 disease of the pear and loquat. It is to prune, and pull, and 

 burn. In case of pear and loquat blight we watched for the 

 withered leaves, which are apt to appear soon after the 

 resinous buds attract the bees or the flowers open their 

 showy petals, and cut them ofi^ a generous distance below 

 the blight as soon as they appear — the sooner the better. If 

 we have been so vigilant as to discover the trouble at the 

 first onset, before the microbes are carried far from the 

 bloom, we shall have stopped the blight entirely. It is safe 

 in case we use our pruning-knife or shears, more than once, 

 to disinfect them before each successive cut, by dipping in 

 a dilute solution of carbolic acid. I hope and expect to save 

 my pear and loquat trees by careful attention to this 

 method. The tomato of California suffers severely from a 

 blight. Great watchfulness and careful pulling of any vine 

 as soon as the blighted leaves make any show, will fre- 

 quently stop the blight at once, and save nearly all our 

 vines. 



Another method that is sometimes very successful in 

 treating blight is to change the locality of the plant. The 

 melons in some parts of California are grievously injured 

 by bacteria that work in the crown and upper roots, causing 

 them to rot. If we go but a short distance from where the 

 blight destroyed the previous year and plant our vines, we 

 often will escape entirely, whereas, if we had planted on 

 the old ground, we might have lost all our plants. 



The last remedy comes from the fact, as often noted, 

 that some varieties resist blight much more than others. 

 The Bartlett pear suffers terribly from pear-blight, while 

 the Flemish beauty often escapes without harm, and the Le- 

 Conte is often said to be more resistant. We may then, 

 often, by growing varieties resistant to the blight, be saved 

 from its ravages. In some parts of our region the very 

 valuable English walnut is sttacked with blight. Prof. 

 Pierce has been growing varieties of walnuts very exten- 

 sively, hoping to secure a variety that shall be utterly 

 blight-proof. I hope that these suggestions may enable our 

 readers to preserve their pet plants from these diminutive 

 but terrible foes. 



A word about the size of these bacteria : They are so 

 small that in order to study them well, we must magnify 

 them very highly. We wish to make them look at least half 

 an inch long. Were we to magnify ourselves in like degree, 

 we would stretch up something more than seven miles. The 

 microbes vary in size from six to twelve hundred thou- 

 sandths of an inch in length. 



It only remains to be said that the moving of bees from 

 any section, while it will work terrible mischief in prevent- 

 ing pollination, will probably avail not at all to lessen the 

 pear-blight. We must remember while it takes thousands 

 of visits of insects to pollinate the flowers of a single tree 

 properly, less than a score are necessary to inoculate a tree 

 thoroughly with this blight virus. There are always enough 

 insects other than bees, not to speak of the unowned bees in 

 rock, crevice, hollow trees, walls of houses, or even in holes 

 in the ground, to spread the virus of the blight so abun- 

 dantly that we can never hope to prevent the spread of dis- 

 ease by keeping the insect away, i >n the other hand, in 

 case of a large orchard, where thousands of trees are often 

 gathered in one block, it is utterly impossible to secure 



