Mussel Scale. 



birds and their larvae eat scale, but none seem very partial 

 to the mussel scale in Great Britain. Minute hymenoptera 

 (Chalcididae) also live as parasites upon them, but seldom do 

 any appreciable good. 



Treatment. 



The only sound advice that can be given to fruit growers is to 

 go on washing and ignore the infinitesimal help given by these 

 minute parasites, also to encourage those useful birds, the tits, 

 in orchard and garden. The trunks, &c, of all trees must be 

 kept clean, i.e., free from rough bark, moss" and lichens. This 

 can be done by washing in winter with caustic alkali wash (see 

 Leaflet 70), which at the same time corrodes and loosens the 

 scales from the trees. Badly infested trees should also be 

 sprayed in the early summer — -about the middle of June — with 

 paraffin emulsion, two or three times, at intervals of a few days. 

 This kills numbers of the young and corrodes away to some 

 extent any remaining scales. Whitewashing the trunks of the 

 trees as far as the forks of the boughs does some good and helps 

 to keep the wood in a healthy state. All young stock should 

 be treated in order to destroy the scale, before or soon after 

 being planted. The best method is fumigation with hydro- 

 cyanic acid gas, the most valuable scale remedy. 



The bushes or young trees should be placed in a box or 

 canvas tent of known capacity and subjected to the fumes of 

 hydrocyanic acid gas for one hour. Large numbers can be 

 treated at once at little expense. After the stock is stacked 

 under the tent or in the box a jar should be placed on the floor, 

 and then water placed in it. Sulphuric acid is added to the 

 water, and then the cyanide of potassium, wrapped in blotting 

 paper, dropped into the acid and water. 



The proportions are as follows : — \ oz. of cyanide of potassium, 

 1 oz. of sulphuric acid, if oz. of water for 250 cubic feet of 

 space. 



This can, of course, be reduced according to the size of the 

 fumigating box or tent. 



It must be remembered that the gas is deadly poisonous to 

 man, and that the cyanide of potassium is also a deadly poison. 

 The fumes must not be breathed. The cyanide should be in 

 small lumps, wrapped in blotting paper, and then dropped into 



