On the Insects affecting the Turnip Crop. 203 



However Mr. Sutton's plan of preparing the fallows for the 

 seed, and leaving the land for ten days or a fortnight before 

 sowing," may have answered occasionally, as his hypothesis is not 

 correct, we must look to other causes for his success, and this is 

 probably the exposure of the chrysalides to drought and changes 

 of temperature, which would naturally destroy them ; the oppor- 

 tunity the weeds have of growing up and overpowering the crop 

 seems to be a fatal objection to this process. I quite coincide, 

 however, with Mr. Cowdry, that the destruction of the beetle may 

 be greatly facilitated by the mode of ploughing he suggests, for if 

 the chrysalides be deeply buried under the furrow, they will perish 

 for want of sufficient sun and moisture to bring forth the little 

 beetles, or even if they hatched, they would not be able to extri- 

 cate themselves from the earth heaped upon them ; this is taking 

 it for granted that the chrysalides are in the soil, which would 

 depend upon the character of the preceding crop. And here 

 again we require inform^ation, for if the maggot of the turnip- 

 beetle will live in the leaves of clover and other artificial grasses, 

 then such a process as deep ploughing becomes aa effective 

 remedy ; if not, it would only be useful where the first crop had 

 failed from the land being infested with the turnip-beetles. 



If the turnip-beetle were not common everywhere in Sweden, 

 it might be presumed that northern latitudes were uncongenial to 

 its habits, for it did not appear to be known in Scotland until 

 1826, and it has done but little mischief, I believe^ since; but this is 

 attributed by Dr. Fleming and others to the turnips being drilled 

 in ; indeed, broadcast is generally considered inferior to drilling, 

 and the system of ridging for the drill is recommended by most 

 farmers. Cold and wet we know do not agree with the perfect 

 insect, and such seasons may be still more pernicious to it in its 

 earlier states, which may account for its rarity in Scotland, where 

 I do not remember to have noticed it, and in parts of Forfarshire 

 and in East Lothian the fly is said to be scarcely known. Mr. 

 Bowie, however, of Arbroath, seems to be well acquainted with 

 the effects of the fly, although he only remembered its attacking 

 the plants once in rough leaf, and that was during the hot and 

 dry summer of 1826. I see also that at Cramond, near Edinburgh, 

 it is now abundant. No notice has been taken of it in Scotland, 

 except on the eastern side, where it may be expected, as in the 

 eastern counties of England, that the fly would be most fatal to 

 the crops, as there is a much less fall of rain on that side than in 

 the western and south-western quarters of the kingdom ; we see, 

 however, from the destruction recorded in Devonshire, that in a 

 warm district, although subject to a great deal of wet, its progress 

 is not always impeded. 



It is the opinion of a great many agriculturists, that raw and 



