528 



and of nine infected by the mouth or fed twice on infected leaves 

 six died. An individual of Lociisfa viridissima, L., inoculated in the 

 third abdominal segment, died in eight days, and the Staphylococcus was 

 reco\'ered from it. Further experiment is advisable with a view to 

 determining the value of this micro-organism against locusts and other 

 insects. 



Miles (H. W.). The Raspberry Gall Fly {Lasioptem riibi, Schrk.).— 

 Jl. Miiiisf. Af^ric, London, xxviii, no. 6, September 1921, 

 pp. 548-550, 1 fig. 



The Cecidomyiid, Lasioptera riibi, Schrk., causes galls on raspberry 

 and blackberry canes, both in hedges and in plantations ; it is becoming 

 increasingly injurious in Kent, and is also reported from Somerset. 

 The galls become noticeable after the leaves have fallen, and 

 when opened are found to contain 15-30 larvae of an orange-red 

 colour. The various stages are described. Oviposition occurs in 

 June, the eggs being laid at the base of the buds and side shoots. The 

 larvae, appearing about eight days later, burrow into the rind and feed, 

 setting up the irritation that results in the formation of galls. The 

 effect of infestation is a stunting of the canes, which may bear no 

 fruit and few leaves. 



A simple remedy is to search the plantations during autumn and early 

 winter and cut off all affected canes below the gall, burning the 

 prunings. IMackberry bushes or hedges near the plantations should 

 be similarly cut back, or, if they are the source of the infestation, they 

 should be destroyed by burning. 



Lloyd (LI.). Cleaning Glasshouses against Red Spider. — Circ. Lea 

 Valley & Dist. Niirs. & Growers' Assoc, Cheskuni, ii, no. 1, 

 September 1921, 4 pp. 



The chief difficulty in dealing with the red spider {Tetranychiis 

 telarius) on cucumbers lies in the destruction of the red fonns in 

 winter. The various positions and crevices in which the mites may be 

 found inside and outside greenhouses are described. Fumigation with 

 sulphur is ineffective when the mites are in hiding ; painting the 

 houses is useful, but does not exterminate them. They can be largely 

 prevented from invading the houses in summer if weeds on the nursery 

 are kept down and hedges kept clean. 



A spray that has been tested with satisfactory results consists 

 of an emulsion of cresylic acid and soft soap. To prepare this emulsion 

 a loose brick furnace with an iron grid .should be built ; the wall 

 above the grid should nearly reach the rim of a bucket on the latter ; 

 1 gal. of 97-99 per cent, cresylic acid (" pale straw") to' 8 lb. pure 

 potash soft soap should be heated in the bucket for 10 minutes over 

 a brisk fire of wood or coke, until the soap has completely melted. 

 This makes 2 gals, of a strong emulsion sufficient for 100 gals, spray, 

 at a cost of about 6s. 6d., and one man can prepare in a day sufficient 

 to spray some 2,000-3,000 ft. of cucumber house. The strong emulsion 

 is used at the rate of 1 part in 50 parts water, or 2 pints in 12 gals. 

 Operators should wear goggles, as the fluid affects the eyes. 



The whole house, plants and surface of the ground should be drenched. 

 During spraying all ventilators should be opened, and closed again when 

 the operation is finished, as the vapour produced has a beneficial 

 effect. All cracks should be carefull}' sprayed. After treating the 



