On the Rust or Mildeiv. 71 



sun upon the roots. Hence the advantages of having a thick, rather 

 than a thin crop ; and hence, it is said, the heneficial effects of mix- 

 ing rye with wheat, the rough bending head of the rye, protecting the 

 earth from the power of the sun. It is also a singular fact, that plants 

 of wheat under trees, escape rust, though the neighbouring crop is in- 

 fested with it. This may be owing, either to the protection from the 

 violence of the sun, or the moisture which is retained in the soil, by 

 the means of the shade thus procured. 



By one or other of these means, and the improvements which may 

 be effected, by the observations of ingenious naturalists, and the ex- 

 perience of intelligent farmers, there is every reason to hope, that the 

 diseases of wheat may, in a great measure, be so mitigated in their 

 effects, that they will not in future be felt as a national calamity. For 

 that purpose, however, it is necessary, that the diligent fanner should 

 seize every opportunity of improving his knowledge in the nature of 

 those diseases, should note down all the circumstances connected with 

 the subject as they occur, and should compare his observations with 

 those of others ; that whether the causes of rust are general, or local, 

 they may, as much as possible, be obviated. He may be assured, 

 that it is " The perfection of good management" to discriminate the 

 causes to which the disorders of grain are owing, and to apply the 

 cheapest and the most effectual remedies. 



No. IV. 



ON THE MEANS OF PREVENTING THE RAVAGES OF 1. SLUGS; 2. 



GRUBS; 3. THE WIRE-WORM; AND 4. THE WHEAT FLY, (OR 

 TIPULA TRITICI,) ON OUR CROPS OF WHEAT. 



AMONG the various difficulties with which a farmer has to contend, 

 in raising his crops, the ravages committed by a variety of the more 

 diminutive tribes of animals, are much more important, and carried to 

 a far greater extent, than is generally apprehended. These vermin 

 are of several sorts ; but the principal are, 1. Slugs; 2. Grubs, or 

 large maggots ; 3. The wire-worm ; and 4. The wheat-fly. The 

 three former devour the plant when young ; the latter attack the ear 

 when it is coming to maturity *. 



It is proposed to give a short account of the various measures 

 hitherto adopted, for preventing the injuries to which our crops of 

 wheat are liable from these destructive animals, accompanied by any 

 recent suggestions for that purpose. 



* Fields of wheat sometimes appear blighted early in the spring, by a small 

 insect of the grub or caterpillar kind, lodged in the centre, or very heart of the 

 stem, just above the root, but the plants afterwards recover, and shoot afresh. 

 The insect is called the musca pumilionis by Linnaeus, from its effects on rye, 

 on which it chiefly feeds in Sweden, rendering the plants it attacks dwarfs. 

 Annals of Agriculture, vol. xvi. p. 170 ; Trans. Linn. Soc. vol. ii. p. 76. 



