THE GARDENERS' CHRONICLE OF AMERICA. 



303 



grown-up plants, known as sleeping sickness. Fusarium 

 parasites nearly always invade the vessels of the plant, 

 thus clogging the upward flow of water. Infected plants 

 droop their leaves as if asleep : they soon wilt and die. 

 Examples of this are the sleeping sickness of tomato, the 

 wilt of the cabbage, and other plants. 



(d) Rhizoctonia Root Rots. — This fungus (Rhizoc- 

 tonia saloni E. & L.) is also a common soil parasite, and 

 is capable of producing damping off of lettuce and many 

 other seedlings. This fungus also produces the well- 

 known "Rosette" disease of potatoes, and it can also at- 

 tack grown-up plants such as the bean, sweet pea, and 

 several others. This fungus produces strangling of- the 

 host, as it is nearly always confined to the cambium, or 

 the vital part of the plant. 



PHYSIOLOGICAL DISE.\SE.S. 



By this is meant any derangement in the health of 

 plants, due to improper soil or cultural conditions, or to 

 too heavy soils, where the amount of air which reaches the 

 roots is rather limited : this results in a sort of asphyxia- 

 tion, in a languid growth, and finally in the death of the 

 plant. The lack of potash in the soil, or of any other of 

 the mineral constituents of the plant, will induce ill 

 health. Overfeeding often also acts detrimentally on the 

 health of the plant. Overfeeding with nitrogenous fer- 

 tilizers in the case of the sweet pea. for instance, will pro- 

 duce a drop of the blossoms, especially of the young buds 

 before they open. In overfeeding, we are apt to furnish 



I'inally, we nuLst not omit the class of higher flowering 

 plants which have degenerated and have adopted a para- 

 sitic life. The dafider is an example of this. 



I have briefly pointed out the different classes of plant 

 diseases. The question, then, is, what can the gardener 

 do to avoid the spread of epidemics and to reduce the loss 

 of his plant by diseases to a mere fraction ? The dictum. 

 "One ounce of prevention is worth two of cure,"' con- 

 tains the key to the solution of the above problem. In 

 our present day of progress where efficiency alone counts, 

 and where specialization is reaching its maximum of per- 

 fection, the gardening profession, too, calls forth from 

 the gardener the best of his brain and efforts. The more 

 we progress the more life becomes complicated, and under 

 these conditions also we complicate the life of our plants. 

 In order to obtain earlier fruits or vegetables, we submit 

 our plants to all sorts of abnormal standards of growth 

 and forcing. Such plants are naturally made less resist- 

 ant to diseases. Moreover, with facilities for transporta- 

 tion, new diseases are constantly brought in from other 

 localities. States and countries into our own locality, gar- 

 den or greenhouse. The asparagus rust, for instance, was 

 known in Europe as early as 1805. It has been since in- 

 troduced in the United States, and it is now found wher- 

 ever asparagus is grown. The same is true of many other 

 plant diseases. While Europe has sent us some of our 

 worst plant pests, we too have given them in turn a good- 

 Iv share. The black rot and the phylloxera of the grape 



CROWX G.\LL 



the plant too much of one element like nitrogen, and very 

 little of the other elements which the plant needs. 



INSECT PESTS. 



The harmful effect of insects are twofold. First, the 

 injury which they inflict on the plant through the biting 

 or sucking, as the case may be, and, second, by carrying 

 and distributing the spores of bacteria and fungi which 

 cause plant diseases. It is well known that the germs of 

 the fire blight of the pear and apple and a host of other 

 diseases are carried and distributed from tree to tree by 

 insects, such as the larvae of beetles, moths, butterflies; 

 also green aphids, red spider, and even liy harmless in- 

 sects, such as bees. Many of the insect parasites pass their 

 life cycles above ground, and confine their injury to the 

 exterior parts of the plants. In this case the means of 

 control are comparatively simple. Same insects, however, 

 pass a part of their life cycle as parasites under the 

 ground : control in this case is more difficult. An example 

 of this is the wire worm. 



BITTER ROT OF .\PPLE. 



OF PEACH. 



are both indigenous to America. Most of the plant dis- 

 eases w^ould not have spread tojextensively had we known 

 earlier to recognize them. 



The infectious nature of 

 plant diseases has only been recognized in the nineteenth 

 century. The science of plant disease is comparatively 

 voung^ and it is only of recent date that this science is be- 

 ing popularized. It is evident how important it is for the 

 gardener to learn to recognize the diseases which attack 

 iiis crops, in order to meet with success in'his preventive 

 measures. But in this, as in any other enterprise, co-op- 

 eration is necessary for success. It is necessary for gar- 

 deners to combine efforts. We may be as careful as pos- 

 .sible. in preventing the spread of plant disease, yet our 

 efforts are futile if our neighbor neglects all sanitary pre- 

 cautions, and allows unchecked the spread of plant para- 

 sites. It is also necessary not only to have the co-opera- 

 tion of our neighbors, but also of the whole community, 

 as well as the laws of the country, in order to prevent the 

 mis-ration of diseases. Thus the gardener, far from op- 

 posing anv attempt of legislation in this direction, should, 



