698 



THE FAKMERS' REGISTER. 



It eecms that ihe taste ofthe turnip-beetle is far 

 less laendious than is getterally imagined. This 

 might be lairly inferred Irom its abounding in 

 eituaiions where the turnip does not grow ; there 

 can be little doubt, however, that it prefers those 

 plants which are teruied crucilerotjs, (iom tlie 

 shape of their flowers, of which cabbages and 

 turnips are exaniples ; of ttieee the leaves of the 

 horseradish, tl.e common turnip, and <he radish, 

 are its favorite Ibod, but cabbasfs, cauliflowers, 

 colewort, waiercresses, ladies'-smocl^s, and hedge 

 mustard, called jack-by-ihc-hedge, are often at- 

 tacked ; the charlock or wild mustard is also 

 sometimes covered with them at the end o( April, 

 and in May the leaves will be seen pierced with 

 holes, but as soon as the turnips come up they de- 

 sert other allied plants. Mr. Berry has recorded a 

 remarkable exception, for he says that after con- 

 suming the cabbai^c plants, the flies* attacked and 

 (festroyed the young hop?, which belong to a very 

 diflerent tribe of plan's. Kollar also states that 

 both summer and winter turnips left for seed 

 suffer in warm and dry weather, from the attacks 

 of the fly injuring the flowers, so as to spoil the 

 produce ol the seed. 



The next subject to be considered is a remedy 

 against the attacks of the turnip beetle, which in 

 some years must cause losses amounting to an 

 enormous sum of money, for so long back as 1786 

 Mr. Young Slated that the turnip crop deeiroyed 

 in Devonshire alone was valued at 100,000/. Now, 

 with regard to the eggs, we see that they are laid 

 on the under side of the rovgh leaf, where they 

 are pretty well secured (rom rain, and also pro- 

 tected by the strong and projecting ribs that sup- 

 port the leaf from any injury that might occur 

 from the leaves being ruffled by the wind or other 

 casualties; and the inferior skin being the most 

 delicate, is best adapted for the eniry of the infant 

 and lender maggots into the substance of the leaf. 

 It is not, therelore, at this stage that much could 

 be done in destroying them. 



The maggots, it is evident, live upon Ihe rough 

 leaf, and do little or no mischief to the growth of 

 the plants ; they dwell perfectly secure between 

 the two cuticles, unless il be when they leave the 

 burrows they had first commenced, probably not 

 of common occurrence, to form new ones at a 

 remote part of the same or upon another leaf. At 

 this period they are most probably aflecied by 

 parasitic enemies. 



The cArj/sa/iS is buried only just beneath the 

 surface of the earth, but it is probably protected 

 in a slight web, forming a cradle for it to lie in 

 free from pressure. 1 think some efibrls might be 

 Euccessfully made for its destruction at this time. 



It is, however, in its last and perfect slate that 

 the mischief is-done. It is the beetle which de- 

 stroys the two first smooth leaves, called ihe cotyle- 

 dons, and the heart of the plant between them, by 

 piercing them like a sieve, destroying the cellular 

 tissuf" and stopping ihe growth ofthe plant. They 

 also leed upon the rou<.'h leaves, drilling them full 

 of round holes, which are larger on the upper 

 than the under side of the leaf; and if the appe- 

 tite of the beetle be not satisfied, he enlarges the 

 aperture, and thus gives it an irregular form, 

 which dilates w'th the growth of the leaf : hence 



* Might not these have been the Altica concinna, 

 or some allied species ? 



the large holes we see at a later period. After all, 

 it is at this stage of their existence, I am inclined 

 to believe, that we can attack them with the best, 

 prospect of success, if they cannot be kept off by 

 other means. 



In collecting the turnip-bceiles by sweeping and 

 various methods, large numbers of small carnivo- 

 rous beetles, belonging to I he Carabi^cB and Staphy^ 

 linidtB,* are Ibund with them ; these probubly feed 

 upon the larvse ; but from the very recent dis- 

 covery of the early stages of the lurnip-beelle, we 

 are yet ignorant of the parasites, of which it may 

 be presumed there are more than one species, that 

 prey upon the niagt^ole and chrysalides ; for it ia 

 a wise dispensation oi Providence to keep every 

 animal in check by some other that is either more 

 powerful or more sagacious than iisellj and this 

 counteracting effect is produced in a degree equal, 

 or eventually sufierior, to the noxious animal, so 

 that in a greater or less space of time the destruc- 

 tive power may be rendered no longer formidable, 

 or be absolutely annihilated by the attacks of its 

 parasites. This natural process, though never 

 failing, is often too slow in its operation to secure 

 immediate relief ; ttie farmer must, therefore, de- 

 vise means, if possible, for the more speedy de- 

 struction ol the enemy. 



The beetles are seldom found in shady places, 

 except during the winter season, and they cannot 

 bear cold and wet, which are great protections 

 against their increase ; it consequently follows that 

 warmth and sunshine are far more favorable to 

 their multiplication, and in such seasons they are 

 most to be dreaded. Showery weather, altera long 

 drought, and cloudy days with gleams of sunshine, 

 also render them abundant,! as such seasons do 

 the greater portion of insects, but, in a lew instan- 

 ces, they have been known to do much mischief 

 even in cold weather. 



That the turnif)- beetle is endowed with an acufe 

 and powerful sense of smelling, is proved by his 

 flying against the wind, and deserting all other 

 plants as soon as a turnip-crop appears in his 

 neiuhborhood. Mr. Le Keux says that in May, 

 1836, when the thermometer was 75" in the shade, 

 during a sou^A u;ind, great numbers were on the 

 wing, and all proceeding southward; and again, 

 that eight acres, forming the summit of a hill in 

 Devonshire, were sown with turnips, and when 

 the young plants were just rising above the 

 ground, the wind being for more ihan a week at 

 south-east, wafting the scent to the north-west, 

 they were so destroyed on this side, that nearly an 

 acre was bare, whilst the souih-east side was not 

 touched, until the plants had attained a size to 

 render the attacks of the beetle of little conse- 

 quence. 



From what has been stated, il appears that no 

 season will secure us entirely against the attacks 

 of the turnip-beetle, and that no soil is considered 

 safe from them is evident upon the best testimony ; 

 it is very destructive upon strong lands ; and not 

 less so on light ones. Neither is the period of 

 their attack limited, for as one pair of insects may 

 produce five or six broods in a season, there is a 

 constant succession, which renders any plan for 



• Curtis' British Entomolog;y folios 446, 758, &c. 



I A field of turnips is stated to have been destroyed 

 by the fly in a few hours before a thunder-storm at 

 Rockingham. 



