294 



On Mildew, Blight, or Rust. 



VoL.V. 



CTs, although the gram generally was worth- 

 less. 



Within the last two years I have heard of 

 many instances of good grain, and but of one 

 instance of mildewed wheat having been pro- 

 duced on lands not sown with grass, or on 

 which there was not a strong growth of grass 

 or weeds ; in every other case of mildew dur- 

 ing that time, I have ascertained, upon inqui- 

 ry, that grass had been sown with the grain, 

 or prevailed to a considerable extent natu- 

 rally. May not the presence of grass, there- 

 fore, be assigned as the cause of mildew or 

 rust? a disease, I believe, but little known in 

 England, where wheat is mostly drilled — a 

 system well worthy of imitation : there, the 

 farmer goes into his fields with his people in 

 the spring, and carefully removes all grass 

 aiid weeds from his crop. There, it is not the 

 custom to sow grass with winter grain ; and 

 the same system is pursued, I understand, in 

 Ireland, France, and many other parts of Eu- 

 rope. Having lately given the subject much 

 reflection, and obtained more information, I 

 feel convinced that I am right in the opinion 

 I have so oflen expressed, that the presence 

 of grass in land in which wheat is being 

 grown, is the cause of mildew or rust, and for 

 the following reasons: — 



Heat is one of the indispensable elements 

 of vegetable vigour and vitality; without it, 

 wheat cannot ripen. The last effort of a stalk 

 of grain is to elaborate its sap to tlie berry or 

 kernel, wjiere it secretes and evaporates its 

 fluids, and this process takes place at the hot- 

 test period of summer. The leaves of the 

 plant having performed their office of sliading 

 the soil, so as to secure sufficient moisture for 

 its vigorous growth, begin now to shrink and 

 dry away, and the scorching influence of a 

 summer's sun, at the season of its greatest 

 power, is brought to act, not only upon the 

 entire stem of the plant, but upon the soil be- 

 neath, and hence, in its last expiring effort at 

 the time of its ripening, it evidently requires, 

 and should enjoy the invigorating influence 

 of the genial heat which is designed and pro- 

 vided for it by nature ; but of the benefit and 

 virtue of this heat, it is oftentimes deprived 

 at the season of its greatest need, the rays 

 of tlie sun being impeded by a heavy coat of 

 grass, which covers the surface of the earth, 

 and is usually about a foot or eighteen inches 

 in height. This matted coat of grass, when 

 thoroughly saturated in moist seasons, by im- 

 peding the sun's rays, causes an excess of 

 moisture in the soil, and preserves the earth 

 at the root of the grain too cold and wet to 

 maintain a healthy vegetation of the plant at 

 its then near approach to a state of maturity. 

 The temperature of the surface soil is there- 

 by rendered much lower than it would be if 

 exposed to the free action of the sun ; an un- 



congenial temperature prevailing in the soil, 

 and a cold, moist and unwholesome atmosphere 

 surrounding the plant at the root, and per- 

 haps for a foot in height upon the plant, 

 checks and renders languid the circulation 

 of the sap, at the very time when nature in- 

 dicates that not only the stalk but the soil it- 

 self should be basking in the heat which pre- 

 vails at that season of the year, and that too 

 at the period when the sun should be exer- 

 cising a drying influence upon it, when the 

 grain is ready to fill and ripen, and when a 

 healthy and vigorous action of the system by 

 means of heat, is most needed for its matu- 

 rity. Hence, we find that wheat in shaded 

 situations, under trees, &c., is green when 

 the rest of the crop is ripe, and is alwaya 

 more or less mildewed. 



I do not wish to be understood as stating 

 that the presence of grass always produces 

 mildew or rust, for I know that good crops of 

 wheat have grown with it in dry seasons ; but 

 I do contend that the presence of a thick coat 

 of grass or weeds upon the surface of the 

 land predisposes the crop to disease or mil- 

 dew, and that in wet seasons it is almost in- 

 variably noxious and hurtful to the wheat 

 plant ; that the uncongenial temperature 

 thereby maintained at the root of the plant, 

 by its being imbedded in too wet and cold a 

 soil, and by its being surrounded to the dis- 

 tance of a foot or more from the ground with 

 a chilled, and, therefore, unwholesome atmos- 

 phere during the day, and at night by a tem- 

 perature equally if not still more injurious, 

 produces a languid circulation, predisposes 

 the plant to become enervated, and finally 

 prostrated ; and it then perishes for want of 

 the vigorous and healthful action of the vital 

 t'unction. 



The want of this healthful circulation pro- 

 duces the disease called mildew, blight, or 

 rust, which first exhibits itself upon the outer 

 skin of the plant, in spots something resem- 

 bling in appearance the rust of iron ; this 

 soon strikes through the stem, and the sap 

 required to form the farinaceous matter in the 

 grain is impeded, entirely checked, or not se- 

 creted. The plant, thus sickened, perishes 

 before its fruit has attained maturity, — hence 

 the grain is not filled, and when dry, it is 

 found to be unripe, shrunk, and almost worth- 

 less. Now, under such influences, have we 

 a right to expect any other than such results? 

 Such causes, if rightly considered, are calcu-' 

 lated to produce anything but a healthy in- 

 fluence i^pon the plant. At the most critical 

 moment of its existence, we shut out from 

 the root the heat which nature has provided 

 to sustain it and promote its maturity, and de- 

 prive it of the power to send up or secrete its 

 sap. We prevent it from enjoying the dry- 

 ing influence of the heat it then requires, and 



