103 



ai~a ?nd, morco\-er, is benelicial to the plants. 



Xaiurc:; : also an important factor: thrushes, 



blackbirr.-^ -^arl::j^\-, Lud also ducks and tOvvl render help 

 in k^-:-p::u- down an excess of Slugs and Snails. 



/i:-::::-, other injurious animals WOODLICE 'S^ and 

 EDE-- '7 were also reierred to but, owing- to the 

 hiixiiia -pace at my disposal, I miist pass over these and 

 deal with the Acari or }vIitls. 1 hey are classified as a 

 group of the Arachnida, v.iiich 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 cephalothcrax. Acari are further 

 distinguished oy the abdomen no-t being clefi.nitely 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 ]\ntes. Erio- 

 phyes ribis \\\ or the BLACK CURRAXI GaLL AIitE is 

 responsible for the Big-Bud " disease which has spread 

 throughout the country. lis presence can be readily 

 detected by the swollen and distorted apoearance of the 

 buds which harbour the Alite. Badly infested buds sel- 

 dom de^relop into shoots, they remain wnc^tened and, after 

 retaining their green coeiv.r for a iin:-:, oeeome brown and 

 die off. The damiage is caused by the jaws of the ^Iite 

 cutting through the e'jidermis of the delicate young leaves, 

 followed by the m-ertin^ of the sucking tube which 

 extracts the sap. Throughout the winter ^he jJite- teed 

 and shelter in the galled buds. Aiigraticn :?.-:_s r rrom 

 the infected ouds, which open from aoout the muddle of 

 April unril well o-n in June. The Antes then crawl out 

 m great numbers in order to hnd new and succulent buds 

 to -erve for their future sustenance. This migration is 

 aided by the habit the Alites 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 ]^Iites 

 commence laying their eggs and thereby multiply rapidly 

 until the end of the summer. Shoots examined during the 

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

 appearance, and are filled with the new generation of the 

 :\Iite, which vsuU carry on infection for the next season. A 

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



