547 



ViNAL (S. C.). The Greenhouse Red Spider attacking Cucumbers and 

 Methods for its Control.— Moss. Agric. Expt. Sta., Amherst, Bull, 

 no. 179, November 1917, pp. 153-182. [Received 17th October 

 1918.] 



Tetranychus telarius {bimaculatus) is the most widely distributed 

 and destructive pest of greenhouse cucumbers, assuming its greatest 

 economic importance in the market-garden district of Boston. Tbe 

 greenhouse vegetables most subject to attack are cucumbers, egg- 

 plants and tomatoes, many individual growers of the first of these 

 estimating their annual losses at between £400 and £1,000. 



Control of the pest on the plants by fumigation is impossible, but 

 fumigation with sulphur dioxide is an inexpensive and efficient method 

 of ridding an infested house of mites in the intervals between crops. 

 Spraying with a strong stream of water, which efficiently controls 

 the pest on certain plants such as carnation, violet and rose, is limited 

 in its usefulness by the tenderness of the forcing-house cucumber 

 foliage. An efficient adhesive spray may be made by boiUng 8 lb. flour 

 in 8 U.S. gals, water to form a paste, and diluting to form 100 U.S. 

 gals. A solution of ordinary laundry starch is also recommended. 

 An equally effective spray can be made by dissolving 1|- lb. ivory soap 

 in 25 U.S. gals, water. The most satisfactorv commercial insecticide 

 is a completely saponified oil soap called lemon oil, contammg : — ■ 

 soap 6 per cent., vegetable oil 3| per cent., potassium carbonate 05 per 

 cent., turpentine (terebenthine) 5 per cent., and water, not over 85 per 

 cent. Used at the strength of 1 part in 20 parts of water, or 1 pint 

 in 2-| U.S. gals, water, it killed all actively feeding and quiescent 

 mites without injuring the fohage, but the eggs were not materially 

 affected. A less expensive emulsion may be made by shaving 6 oz. 

 ivory soap into 1 U.S. gal. hot water, adding 2 U.S. qts. cold water and 

 1 U.S. qt. linseed oil and emulsifying with a bucket pump ; this, when 

 used at the rate of 1 part in 9 parts water, is very efficient, killing 

 quiescent and feeding mites without injuring the leaf -tissue. The 

 effectiveness of raw linseed oil is partly due to its being a contact 

 poison, but chiefly to its adhesiveness. Beins composed of two types 

 of oil, drying oil and resinous oil, it rapidly volatilises when applied 

 as a film, leaving the resinous or waxy residue enveloping any mites 

 present on the leaf. To effect a thorough control, at least three 

 applications should be given to the young plants at weekly intervals,, 

 as soon after they have been set out in the greenhouses as possible, 

 cool, cloudy days being chosen for the operation. 



EssiG (E. 0.) & KuwANA (S. I.). Some Japanese Aphididae.— Proc. 

 California Acad. Sci., San Francisco, viii, no, 3, 9th July 1918, 

 pp. 35-112, 40 figs. [Received 2nd November 1918.] 



This paper, which has been prepared as an introduction to the 

 study of Japanese Aphids, includes the following species : — ■ 

 Macrosifk^im absinthi, L., on Artemis vulgaris indica ; M. granariumy 

 Kirby, on rice ; M. hagi, sp. n. , on Lespedeza bicolor (hagi) ; M. ibotum^ 

 sp. n., on the under-sides of the leaves of Ligustnmi ibota ; M. nip- 

 ponicum, sp. n. ; M. yiishigaharae, sp. n., on Chrysanthemum ; M. rosae, 

 L., on Rosa multiHora ; M. rudbeckiae, Fitch, on Boltonia indica, 



