Disease in plants

We have seen that all the essential phenomena of disease concern only the living substance--the protoplasm--of the plant, and that however complex the symptoms of disease may be...

It is customary to regard the soil, between the particles of which the root-hairs of plants are distributed, as if it were merely a dead matrix of smaller or larger pieces of ro...

I put together in one artificial class a varied group of diseases, the principal symptom of which is the escape of fluids from the tissues, under circumstances which betray an a...

In the more hopeful view of the case which the new agriculture will have to take, it will recognise the physiological truth that since the living plant is the important and vari...

_Quantities of starch formed, and their significance for the plant. The absorption of energy--the conversion of energy in the plant. The plant is a complex machine for concentra...

Physiological research has shown that the respiratory activity of cells may be increased by small doses of poisons, and even that growth may be accelerated by them--_e.g._ chlor...

_Wounds._--All the parts of plants are exposed to the danger of wounds, from mechanical causes such as wind, falling stones or trees, hail, etc., or from the bites of animals su...

_General and local disease--General death owing to cutting-off supplies, etc.--Disease of organs--Tissue-diseases, e.g. timber--Root-diseases--Leaf-diseases, etc.--Diseases of R...

If the living root-hairs are so numerous and so active, however, a natural inference is that they must exert some influence on the composition or arrangement of their environmen...

Among animals, the various vertebrata, including man, are especially responsible for the larger kinds of wounds and wholesale destructive processes due to breakage, stripping of...

_Predisposition and immunity--Pathological conditions vary--Hardy varieties--"Disease-proof" varieties--Disease dodging--Thick skins--Indian wheats, etc. Cell-contents vary--Cit...

_Monstrosities._--In a wide sense this term is applicable to many cases here treated under other headings, and signifies any departure from the normal standard of size, form, ar...

When we come to enquire into what circumstances bring about those severe and apparently sudden attacks on our crops, orchards, gardens, and forests by hosts of some particular p...

On the roots of most plants are to be found delicate, silky-looking, tubular prolongations of some of the superficial cells, known as root-hairs. Malpighi (1687) seems to have b...

It may be said that in no connection is the proverb "Prevention is better than cure" more applicable than with this subject, and undoubtedly the best utilitarian argument that c...

_Excrescences_, or out-growths of more or less abnormal character from the general surface of diseased organs, are very common symptoms, and widely recognised. They are due to h...

It is customary to classify the causes of disease in plants into two principal groups--(1) those due to the action of the non-living environment--soil, atmosphere, physical cond...

Grafting is a process which consists in bringing the cambium of a shoot of one plant into direct union with that of another, and is practised in various ways, the commonest of w...

The year 1860 may be regarded as a landmark of importance in the history of plant physiology, for it was in that year that Sachs discovered that the bringing together of water a...

The relations of the plant to the environment can only be understood by taking into account the results of modern physiological discoveries. These teach us that the living plant...

When we come to enquire into the causes of disease, it appears at first an obvious and easy plan to subdivide them into groups of factors which interfere with the normal physiol...

_Discoloured spots_ or patches on the herbaceous parts of plants, especially leaves, furnish the prominent symptoms in a large class of diseases, due to many different causes, a...

Natural wounds are produced in a variety of ways during the life of the plant, and, generally speaking, are easily healed over by the normal process if the area destroyed is not...

Everybody knows in a general way when the geraniums in the window pots are drooping from want of water, or when the young Wheat is sickly, or the Pear-trees "blighted," and we h...

_Dissemination of fungi by the aid of snails, rabbits, bees, and insects--Man--Distribution in soil, on clothes, through the post, etc.--Worms, wind--Puffing of spores--Creeping...

If I were asked to sum up the most important result of the numerous advances made during the past decade in agriculture and forestry, I should reply--the clearer and wider recog...

_Necrosis._--This is a general term for cases where the tissues gradually turn brown or black in patches which die and dry up, the dead area sometimes spreading slowly and invad...

Phytopathology, from Greek words which signify to treat of diseases of plants, comprises what is known of the symptoms, course, and causes of the diseases which threaten the liv...

_Proliferation_ consists in the unexpected and abnormal on-growing or budding out of parts--stems, tubers, flowers, fruits, etc.--which in the ordinary course of events would ha...

_Cankers_ are irregular excrescences due to the perennial struggle between tissues attempting to heal up a wound, and some organism or other agent which keeps the lesion open. A...

The detailed study of the anatomy and histology of Galls has been recently undertaken by Küster, "_Beitrage zur Kenntniss der Gallenanatomie_," Flora, B. 87, 1900, p. 117, where...