322 THE TURNIP CROP. 



even then that frequently is limited to the district of their 

 ravages. So far back as 1 783, we find, in the Philosophical 

 Transactions of the Royal Society, notices of the destruc- 

 tive visits of these caterpillars, extending over thousands 

 of acres, which they entirely cleared off; and a few years 

 later (1786), that the loss sustained by the ravages of the 

 "fly" in the county of Devon alone, was estimated by 

 Dr. Young at 100,000. At the present day, travel which 

 way you will, everywhere the turnip fields give evidence, 

 by their blanks and deficiencies, of some causes operating 

 against the farmer's crops. What the deficiency through- 

 out the country may be from their individual or combined 

 ravages, could, in the present state of our statistical and 

 other knowledge, only be guess-work. We have some data, 

 however, in the recent statistical returns of Scotland, 

 where, in 1857, we find the area under ' turnips to be 

 476,691 acres, while the entire produce amounted only to 

 6,690,109 tons, equal to about 14 tons per acre; whereas 

 we may fairly estimate the productive capability of Scot- 

 land, with its good farming and congenial soil and climate, 

 to average 20 tons to the acre, if the crops were not dimi- 

 nished by insect injuries. This would show a loss of from 

 25 to 30 per cent, of their entire crop. If this estimate is 

 correct for the north, what must the loss be in the south, 

 where the turnip cultivation is less attended to, and the 

 soil and climate less congenial to turnips, and more con- 

 genial to insect growth? Happily for us, these destructive 

 pests are always accompanied by certain parasitic insects, 

 which live upon them and thus keep down their numbers ; 

 whilst pheasants, partridges, rooks, starlings, lapwings, 

 and a host of smaller birds, live at certain seasons of the 

 year entirely upon them. 



As may be supposed, many remedies have been recom- 

 mended from time to time for the purpose of preventing or 

 lessening the injuries they commit. One simple remedy, 



