103 



Slugs and Snails and, moreover, is beneficial to the plants. 

 Natural enemies are also an important factor: thrushes, 

 blackbirds, starlings, and also ducks and fowl render help 

 in keeping down an excess of Slugs and Snails. 



Among other injurious animals WOODLICE (8) and 

 MILLIPEDES (7; were also referred to but, owing to the 

 limited space at my disposal, I must pass over these and 

 deal with the Acari or MlTES. Ihey are classified as a 

 group of the Arachnida, which also includes Spiders, 

 Harvestmen, and Scorpions. All can be recognised by 

 the presence of eight pairs of legs, the absence of feelers 

 or antennae, and the fusion of the head and thorax into 

 one compact region or cephalothorax. Acari are further 

 distinguished by the abdomen not being definitely marked 

 off from the rest of the body. The Red Spiders or Trom- 

 bididae belong to this group, but the most important for 

 our purpose are the Eriophyidae or Gall Mites. Erio- 

 phyes ribis (4) or the BLACK CURRANT GALL MlTE is 

 responsible for the " Big-Bud " disease which has spread 

 throughout the country. Its presence can be readily 

 detected by the swollen and distorted appearance of the 

 buds which harbour the Mite. Badly infested buds sel- 

 dom develop into shoots, they remain unopened and,, after 

 retaining their green colour for a time, become brown and 

 die off. The damage is caused by the jaws of the Mite 

 cutting through the epidermis of the delicate young leaves, 

 followed by the inserting of the sucking tube which 

 extracts the sap. Throughout the winter the Mites feed 

 and shelter in the galled buds. Migration takes place from 

 the infected buds, which open from about the middle of 

 April until well on in June. The Mites then crawl out 

 in great numbers in order to find new and succulent buds 

 to serve for their future sustenance. This migration is 

 aided by the habit the Mites possess of often attaching 

 themselves to passing insects wandering over the twigs. 

 By this means they become distributed to other branches 

 and to fresh bushes. Strong winds are also a factor aid- 

 ing their dispersal. Having entered new buds the Mites 

 commence laying their eggs and thereby multiply rapidly 

 until the end of the summer. Shoots examined during the 

 end of August and in September, exhibit the " Big-Bud " 

 appearance, and are filled with the new generation of the 

 Mite, which will carry on infection for the next season. A 

 certain number of eggs are to be found all the year round 



