No. 10. 



On Blight. 



899 



tilate and keep all dry, and you will radically 

 cure both the rots, the veoetable of which, 

 being transplanted to a dry situation, will 

 perish. Thus, in the case of dry rot in tim- 

 Der, if our curiosily be attracted by the orenc- 

 ration of the fungus, our serious altenlion 

 lought to be bestowed on those humid exha- 

 lations which are its original cause. 



The general explication of the terms em- 

 ployed in this subject, which I propose, is 

 as follows : — By blight — in Latin, uredo — is 

 understood a morbid aftection of vegetables 

 from some external cause, by which tiiey are 

 at once withered and destroyed, or suffer a 

 change of colour and gradual decay. Mil- 

 dew — crysiphe — is the 7«ucor or mould de- 

 posited on the surface of vegetables and other 

 substances during the act of evaporation. 

 Mildew is of various colours, and when it 

 appears upon the stalks and ears of grain, 

 and assumes the state and colour of the rust 

 or mould of iron, it is denominated Rust — 

 urbigo — and when black, black rust. Brand, 

 burnt, or blast — ustilago — is the partial or 

 total disorganization of the ear of grain, so 

 that it may be reduced to powder by the 

 touch. Red-gum is a viscous substance, 

 generally exuding from the joints of the 

 stalks, and often found upon the leaves of 

 green grain. Smut is the pungent scent of 

 vegetable putridity, issuing from smut-balls 

 or kernels of wheat or other grain, withered, 

 decayed, and in a putrid state ; or from entire 

 kernels slightly infected, and contaminated 

 by the putrid material. Honey-dew is an 

 unctuous and sometimes sweetish moisture, 

 covering the leaves of trees and plants ; it is 

 the usual concomitant of blight. Curl or 

 cling, is a contraction of the vegetable leaves 

 — one of the most constant and invariable 

 effects of blight; leaves are also curled by 

 the action of caterpillars and other insects, 

 and by stagnant moisture. 



Now, it will appear from this arrange- 

 ment, that although the above terms have 

 been, in the popular way, supposed to de- 

 note different diseases, yet, in fact, they are 

 merely the different effects or stages of one 

 and the same disease, namely — atmospheric 

 blight; — I repeat, the atmospheric disease — 

 nestling and depredations of insects, which 

 we know survive through the winter — the 

 caterpillar most particularly — will cause a 

 sickliness and withering in vegetables, which 

 assumes the appearance, and is usually de- 

 nominated blight : this species of blight is, 

 however, of trifling importance when com- 

 pared with the atmospheric, and is distin- 

 guished with the utmost facility by the prac- 

 tised eye. The probable reason for that mul- 

 titude of caterpillars produced in a blighting 

 season is, that such seasons are usually pre- 

 ceded by a mild winter; hence, the direful 



ravages of Locusts, Hessian Flies, and va- 

 rious genera of insects in warm climes, or 

 countries within the flights and migrations 

 of winged insects. 



But our most material business is, with 

 grain under the influence of blight; and sin- 

 gular enough it is, that in the general suppo- 

 sition, wheat alone should be liable ! Doubt- 

 less, the superior importance of that precious 

 grain has absorbed the public attention; yet 

 every other species of grain, rye, oats, bar- 

 ley, beans, peas, are also liable to the dis- 

 ease in all its forms, although not to be af- 

 fected by smut in an equal degree wilii wheat. 

 Oats have been, this summer, much affected 

 by ustilago or brand, and the smutty scent 

 of the ears gathered in the field has been, 

 occasionally, very pungent: these defects, 

 observed in samples of barley and oats, 

 known by the name of moiu-burnf, foxed, &c. 

 frequently originate in atmospheric disease. 

 Mildew, 1 have observed, may with propriety 

 be divided into two varieties, which, until 

 better terms can be found, may be denomi- 

 nated the dry and the wet — a liberty which 

 I have previously taken with the rot in tim- 

 ber; in truth, there is much analogy in the 

 cases. The dry mildew is that which is 

 brought upon the vegetable surface by the 

 atmospheric stroke or blight, appearing at 

 first like a high blooming blue colour, and 

 even as the harbinger of health and luxuri- 

 ance, but afterwards progressively degene- 

 rating into a plainly morbid but deeper blue; 

 this is the bottle-green, formerly pointed out 

 by various writers as the precursor of smut; 

 and most undoubtedly, so it is. The wet 

 mildew, or the mould of damps, is matter of 

 every one's observation, amongst others, of 

 the bad housewives, who leave their linen to 

 continue for a long time so closely packed 

 together, that it becomes mouldy ; but a still 

 more apt example is, the mould of hay, 

 stacked in too moist a state; this mould or 

 mucor is a fungus production from stagnant 

 moisture or humid vapours, and seems to 

 originate in a precipitate from the decompo- 

 sition of moisture or of humid air, and is 

 seen on the surface of cold and wet land, and 

 of unventilated water ; its general appearance 

 is green and mossy, but on some land of a 

 rusty colour. A material of mildew is also 

 under heaps of wet vegetables or in the damp 

 earth, in the form of white filaments, of a 

 strong mushroom smell : thus grain may suf- 

 fer from the wet mildew even whilst in the 

 grass, if it stand very thick on the earth or 

 be beaten down, and remain wet and unven- 

 tilated, and is afterwards far more liable to 

 be alfected ; and continued rains or dews, 

 especially in the autumn, may have the same 

 effect ; the vegetable juices becoming chilled, 

 obstructed, stagnant: hence, according to the 



