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concerned, the tide of these insects is about to ebb, and that there- 

 fore the disease will disappear, or, at least, go back to its original 

 bounds, as I do not believe it to be of so recent date as is supposed. 

 1 have remarked that potatoes have suffered most with a northern 

 aspect. May it not be that these creatures are a squadron of the 

 'great nortljern array V I think it is about 100 years since the curl 

 prevailed to an alarming extent in the south of England; and we still 

 have it in a mitigated form. There are other insects found on pota- 

 toes, such as beetles, &c., &c. Some of them have been erroneously 

 supposed to be the enemy, whereas they are waging war upon him. 

 It appears to me that there are two great divisions of insects, those 

 which attack the vegetable kingdom when in health, such as the 

 Aphis, caterpillar, &c., and those which act as scavengers when decay 

 has set in, such as grubs, beetles, &c. In 1847, I had a field of beans 

 blackened in one night. The canker of trees is often, in my opinion, 

 caused by insects. To me, it is rather surprising that a cause so sim- 

 ple, usual, and manifest should be doubted. I have found varieties 

 of these insects on many plants ; and in every instance there was the 

 blackened leaf. Is it to be wondered at, the potato, a delicate and 

 not an indigenous plant, being thus injured, and the regular flow of 

 the sap intercepted, that the decay of the tuber should follow ? I 

 improved much on the plan that I recommend to sweep off these ver- 

 vim, the results of which I may possibly bring before you at another 

 time. No doubt, much might be done to check these blights, even 

 in the manuring of the potato. Peat-charcoal or lime has been bene- 

 ficial, and should be used instead of, or, at least, in conjunction with, 

 other manures. I would also recommend early planting, as the plant 

 would thus have a chance of coming to maturity before being attacked. 

 My potatoes are the best that I have had for years ; whilst my neigh- 

 bours in that mountain district have scarcely any. The oat crop in 

 many parts of Ireland was, last year, what is called blighted. I found, 

 one morning, after walking through a field, that my clothes were 

 covered with what appeared a yellow dust ; but I discovered, on exa- 

 mining well, that every particle had life — 



' Full nature swarms with life, one wondrous mass 

 Of animals or atoms organised.' 



The following day it was not observable. What if the grain crops 

 now are to suffer ? Here, also, as with the potato, some varieties 

 escaped better than others ; and those sown early were better than 

 those sown late. Now, although we should not be able to do much 

 VOL IV. 5 Y 



