1909.] The Insect and Allied Pests of the Hop. 621 



suppress. Great pressure is sometimes employed in spray- 

 ing, but this is undoubtedly bad for a delicate plant like the 

 hop ; the leaves get blown off and bruised, and where certain 

 washes have been employed I have seen as much harm done 

 as by the lice. 



Paraffin emulsions are sometimes recommended and used 

 for Hop Aphis, but, like liver of sulphur, their effect on the 

 foliage is uncertain, and frequently much scorching results. 

 Paraffin has, however, been used in certain patent washes 

 without any serious results. On the other hand, soap and 

 quassia or nicotine are quite innocuous. The quantity of 

 soft soap used varies from 4 up to 12 lb. per 100 gallons, 

 with 6 to 8 lb. of quassia. If nicotine is used, the minimum 

 quantity of soap will do. If soft soap alone is used, and this 

 will readily kill Aphis, as much as 10 to 12 lb. is required; 

 below 8 lb. I have not found it strong enough to kill Aphis. 



The quassia is sometimes steeped in cold water, and 

 the extract mixed with the soap. If this is done, not nearly 

 so much is got out of the quassia as if it is allowed to simmer 

 in bags for some hours, and then the soap added, and both 

 boiled together. The bags can then be withdrawn, and very 

 little bitter extract can be obtained again. Tobacco may also 

 be used, or pure nicotine. If the latter, I find that 6 oz. of 

 98 per cent, nicotine are sufficient for 100 gallons, plus the 

 soap; if tobacco, about 2 lb. to the 100 gallons is enough. 

 Roll tobacco seems to be the best to use. 



Earwigs. 



(Forficula auricularia and Labia minor,) 



Both the large and small Earwigs are found on hops in 

 some numbers in certain years. The large Earwig seldom 

 flies; the small one is constantly on the wing. 



The only case of damage caused by these insects that has 

 come to my notice was in 1899, when large numbers of them 

 occurred on hops at Wye. They were watched biting the 

 young and tender leaves, which, as they grew out, assumed 

 a stunted and ragged appearance. In many hills growth was 

 quite stopped. The majority of the Earwigs hid away during 

 the day under clods of earth and in the soil ; a few sheltered 



