56 Observations on Insects affecting the Turnip Crops. 



the diseased leaves as soon as the presence of the insects is de- 

 tected, and crush them completely under foot, or put them into 

 a sack and carry them away to be destroyed with boiling- water. 

 Watering the plants with equal parts of tobacco-water and lime- 

 water is said to be the best mode of destroying the Aphides in 

 gardens ; and if plants he washed with tobacco-water alone — 

 about half a pound of tobacco to a gallon of hot water — it will 

 kill the Aphides ; and if applied warm it will kill them the 

 sooner. Strewing tobacco on hot cinders will soon rid a green- 

 house of this pest ; and sprinkling tobacco-dust upon trees when 

 the dew is upon the leaves is an infallible remedy : but these 

 applications would avail but little in the field even if it were prac- 

 ticable to employ them. Sprinkling of lime-dust is likewise con- 

 sidered a very effective cure, but not in wet weather,, when the 

 lime not only loses its caustic quality, but the Aphides so perfectly 

 secrete themselves, that it is impossible to annoy them : I have 

 been astonished to see plants swarming with them on the first 

 dry day after long- continued and very heavy rains. 



Fortunately, no tribe of insects has a greater number of natural 

 enemies to keep it in check than the plant-lice; for besides 

 sw^allows, robins, and numerous insectivorous birds, various bugs, 

 spiders, beetles, and wasps destroy vast quantities ; but the 

 larvae of the lady-birds, of the bee-like syrphus, of the golden-eyed 

 flies,, and several minute ichneumons, are pre-eminently useful, 

 and particularly deserving of our attention : so much so, that on 

 the continent gardeners collect the larva? of the lady-birds and 

 syrphidae, and put them upon their rose-trees, &c. ; for as they 

 subsist entirely upon Aphides, they soon clear a plant of these 

 troublesome and offensive little pests. I shall now endeavour to 

 make the agriculturist better acquainted with the instruments pro- 

 vided by Providence to subdue a tribe of insects, which, without 

 such parasites, would, like the plagues of Egypt, cover the land. 



One of the most conspicuous and efficient enemies are the 

 CoccinellcE, of which about thirty different species have been 

 noticed in England,* varying amongst themselves in colour and 

 markings, to as great an extent as any of our domestic animals. 

 These pretty beetles, called lady-birds and lady-cows, seem to be 

 under the especial care of the Creator : for they have secured the 

 affections and good feeling of our children, and are amongst the 

 few insects which in this country we are taught in our infancy not 

 to regard with disgust or horror. The same kindly feeling is ex- 

 tended to them in France, where they are almost held sacred, 

 being called vache a Dieu, and betes de la Vierge, or '' God's 

 cows," and '^ the Virgin's insects." The lady-birds hybernate 



* Curtis"s Brit. Ent., fol. and pi. 208, and Guide Genus, 438. 



