THE GARDENERS' CHRONICLE OF AMERICA. 



819 



pays his morning visit, that many, if not all, of the con- 

 tents of the houses and frames are frozen. In some in- 

 stances he is, perhaps, to blame; but even in the best 

 regulated gardens accidents of this kind will occur, and 

 it is as well to know the best course to adopt under 

 these or similar circumstances. Believing as we do 

 that prevention is better than cure, it is advisable to 

 remember that plants which are in a comparatively dry 

 state suffer far less from frost than those of a similar 

 kind, whose tissues are turgid with moisture ; hence 

 the wise gardener will see to it that they have the 

 lowest possible quantity of water during frosty 

 weather, without, of course, allowing them to suffer 

 in that direction. The reason is this : As every stu- 

 dent of plant physiology is aware, a plant is made up of 

 innumerable thin-walled cells, and that these are more 

 or less filled with moisture. When this becomes frozen 

 it, under a natural law, expands and the delicate walls 

 of the plant cells are ruptured. It is thus obvious that 

 the more highly charged these cells are with moisture 

 the greater will be the damage to the cell walls; hence 

 the advice to lie sparing with water during frost. 



But nattirc, in her wisdom, has to some extent pro- 

 vided against damage by this rupture of the cell walls, 

 and it is quite possible for the tissues to right them- 

 selves, providing the conditions for doing so are favor- 

 able; hence the gardener who is conversant with these 



conditions is well on the way to saving, it may be, a 

 valuable lot of plants, some of which it might be exceed- 

 ingly difficult, if not impossible, to replace. Briefly, the 

 conditions favorable for recovery are very slow thawing. 

 It is sudden thawing, brought about, it may be, by 

 a burst of sunshine or correction of the heating ap- 

 paratus, that is so disastrous to frozen plants. Know- 

 ing the cause of damage and the conditions best suited 

 for minimizing it, the cultivator will not be slow to 

 bring about such conditions. First of all, the houses or 

 frames should be shaded if there is danger of sunshine ; 

 then the whole of the frozen plants and woodwork be 

 syringed with water that is as near freezing point as 

 possible, keeping this up until satisfied that frost has 

 departed. This will be an exceedingly cold and un- 

 pleasant task, but one that may mean the difference be- 

 tween saving and losing most of the plants. It will be 

 necessary to keep them as cool as possible, without let- 

 ting frost actually reach them, for a few days after- 

 wards. This treatment applies to all forms of plant- 

 life, whether hard-wooded, like the Rhododendrons and 

 Camellias, or soft-wooded, like the Chrysanthemums 

 or Primulas. The chief points to observe are to keep 

 the water supply at the roots as low as possible, and, 

 in the case of the plants being frozen to shade them for 

 some hours, and to syringe them overhead with icy 

 cold water. — The Garden. 



The Why's In Plant Disease Control 



By J- J- Taubenhaus. 



It seems that some of our most common diseases among 

 plants of today have long been known. Mildews and 

 blights are referred to both in the old and in the new tes- 

 taments. Nevertheless, the active agents causing plant 

 diseases were not known until the beginning of the nine- 

 teenth century. Scientific studies have proven that rots, 

 blights, mildews and cankers are true diseases and caused 

 by specific organisms. However, these facts have been 

 slow to gain ground among growers. Even today there 

 are some who still spend hours in arguing that organ- 

 isms which cause diseases are a myth and not a reality. 

 No doubt there are some who still regard epidemics, 

 blights and rots as punishment for certain misdemeanors. 

 If plant diseases were not of an economic natiu"e, this 

 article would not be justified. They cause great loss an- 

 nually to our cereals, forage crops, fruits and vegetables. 

 It was estimated that in 1898, in the United States, wheat 

 rust alone produced a loss of $67,000,000. {'each leaf 

 curl in 1900 caused a loss of $2,335,000. In New York 

 potato late blight in 1904 caused a loss of $10,000,000. 

 Oat smut causes an annual loss in the United States of 

 $6,.S00,C00. Loose smut of wheat produces an annual 

 loss of $3,000,000. If we were to estimate the total loss 

 from disease to all the crops in the United States, the 

 figure in dollars would be appalling. 



Plant diseases are increasing every year, because of 

 our highly developed means (if communication and travel. 

 New diseases are constantly brought in from the old 

 world and we. too, are sending it our share of trouble. 

 Can we remain indifferent to all this? Are we to allow 

 the best of our energies to be sapped by these parasites? 

 .\re we to hand over to our sons weakened strains nf 

 crops and soils rendered sterile by disease producing or- 

 ganisms? The science of i)lant disease has definitely 

 proven that most of these diseases may be controlled and 

 these losses reduced to a minimum. This can be accom- 

 Ijlishcd by the different means of control which I shall 

 licrc cnnineratc : 1. spraying; 2. surgery; 3, seed treat- 



ment; 4, soil treatment; 5, sanitation; 6, resistant varie- 

 ties. 



Why we spray. — Plant diseases may be caused by a 

 number of parasites. The chief ones are fungi and bac- 

 teria. These and particularly the fungi reproduce by 

 means of spores which correspond to the seeds of the 

 higher plants. The spores may be carried from diseased 

 to healthy plants by means of winds, rain or drainage, 

 water, implements, hoofs of animals and even by man. 

 In a diseased area the air n»ay be full of these particular 

 disease producing germs. The spores readily lodge on 

 any part of a healthy plant and with a moist atmosphere 

 germinate and renew its course of the disease. Spray- 

 ing is not a cure but a preventive. Treatment after the 

 spores have begun to grow and have penetrated the plant 

 tissue is of no avail. The philosophy of spraying, there- 

 fore, is to coat all parts of a healthy plant with a fungicide 

 dilute enough not to kill the plant, but strong enough to 

 kill or prevent the growth of the spores which fall on 

 that plant. It seems that all great discoveries are acci- 

 dental. Spraying, too, is an accidental discovery by a 

 l-'rench .scientist. In the eighteenth century it was cus- 

 tomarv in the grape regions of France to sprinkle in the 

 vinevards a few rows of grape vines near the road with 

 a liquid mixture of lime and bluestone. This was <lone 

 to give the treated plants a poisonous appearance, and 

 thus ward off tempted hungry invaders. From 1878 to 

 1880 France suffered great loss from the downy mildew 

 of the grape. The French scientist. Millardet by name, 

 had noticed that grape vines sprinkled with the lime and 

 bluestone solution suffered the least from the mildew. 

 I'.xperiments were at once begun and it was found that 

 the bluestone (copper sulphate) in the mixture prevented 

 infection from mildew. This discovery laid the founda- 

 tion for preventive treatment of plant (liscascs. 



Spraying has received the greatest attention and study 

 in this country, and it is here that it has reached a high 

 degree of ])erfection. Commercial firm? are cooperating 



