40G 



Ohser^vations on the various Insects 



smaller in size than those sent last year: not yet, I presume, 

 having- attained their full growth. The crop is so totally de- 

 stroyed, that it is of no use attempting any method to remove the 

 insects by lime or otherwise ; but it would be very satisfactory to 

 ascertain their origin, and by judicious measures to prevent their 

 reappearance at a future time. The mangold- wurzel is the only 

 crop attacked in a field sown with potatoes, turnips, peas, and 

 beans." With the larvae were enclosed some of the leaves which 

 were amongst the least injured, the greater part of th« plants 

 having been completely eaten down to the root. 



I learn, by a recent communication from Mr. Ogilby, that the 

 depredations of these larvae are not confined to Londonderry, for 

 they have made their appearance this year upon his property in 

 the next county of Tyrone. He says, A much larger breadth 

 of root-crops of all kinds, including mangold-wurzel, was put 

 down last year by my tenants than during any former season ; 

 partly owing to the failure of the potato-crop, and partly to the 

 offer of very large premiums on my part. Turnips, parsnips, 

 carrots, and cabbages have succeeded admirably ; but of the man- 

 gold-wurzel the whole crop was cut off by the insects, before 

 the cotyledon leaves had well penetrated to the surface — as soon 

 as ever they appeared the plants were attacked, and I may almost 

 say that they were never seen, so rapid was their destruction. 

 One crop, and, as far as I am aware, one alone in my neigh- 

 bourhood, that of the Rev. Mr. Brownlow, of Alia, succeeded — ■ 

 or, I should rather say, escaped." 



In manuring Mr. Maxwell's field, no bones or offal, beyond 

 what might have been accidentally thrown on a dunghill, had 

 been used. This was in answer to my supposition that these 

 larvae had been introduced into the mangold-wurzel fields with 

 the manure, either bones or seaweed ; such does not appear to 

 be the case ; but with the few facts we have at present collected 

 relative to this new pest, attention must be given to every col- 

 lateral bearing. It seemed desirable to report Mr. Maxwell's 

 observations as fully as possible, in order that the subject may be 

 carefully investigated, lest the cultivation of this valuable crop 

 should be abandoned in Ireland ; and it is very remarkable that 

 although the insect is abundant in England, I have not heard an 

 intimation of its appearance upon the mangold-wurzel. Indeed, 

 at present, it is unknown on this side of the water as an enemy to 

 the agriculturist. 



It is not so, however, in France; for we learn from M. Guerin 

 Meneville,* who is indefatigable in the pursuit of every branch 

 of entomology, and has lately devoted himself to investigating the 



* Annales de la Soc. Ent. de France, for 1846, p. Ixxii. 



