423 



Many of the insects are left in the debris remaining after the seed 

 is cleaned ; this should therefore be burnt to destroy them. The 

 seed should be disinfected a fortnight or a month after the harvest. 

 This is done by tightly closing the storehouse and heating to a 

 temperature of 65° to 70° F., which must be maintained for a week. 

 This causes the insects within the seed to develop and emerge 

 prematurely, especially if the seed be stirred. The building should 

 then be fumigated with 2 lb. carbon bisulphide per 700 cu. ft. of 

 space, and left closed for live days, after which it may be ventilated 

 and the dead insects separated from the seed. 



Los Trips del Palto y de la CeboUa. [Thrips of the Avocado Pear and 

 Onion. J — Serv. Policia Sanit. Vej., Santiago de Chile, 1919, 

 10 pp., 7 figs. [Received 4th July 1921.] 



Heliothrips haemorrhoidalis is a well-known pest of greenhouses 

 and of many outdoor plants in Europe. In Chile it was observed 

 in 1915 in greenhouses where azaleas, rhododendrons, heliotrope, and 

 other delicate plants were being grown. It is now a pest of consider- 

 able importance on avocado pear and lemon trees. It increases 

 with extreme rapidity, and on badly infested trees causes the leaves 

 to drop and the fruit to remain undeveloped or become defective. 



The remedy suggested is a paraffin emulsion, made of 12 oz. 

 soap in 1 gal. boiling water, to which 1 gal. paraffin is added. A 

 further 14 gals, water is then added and the paraffin well mixed in. 

 For very young or delicate plants, a decoction of tobacco should be 

 prepared by heating 100 gals, water and adding at the moment of 

 boiling 30 lb. tobacco or tobacco dust and 2 lb. carbonate of soda. 

 This should be boiled for half to three-quarters of an hour and strained 

 through a cloth. Calcium polysulphide (15°Be.) is then mixed with 

 water in the proportion 1| gals, to 10 gals, water, and 2| lb. iron 

 sulphate in another 10 gals, of water. These two mixtures are stirred 

 together and a paste of 4 lb. flour to 10 gals, water is mixed in. 

 The tobacco decoction is then added and the whole is ready for use. 

 Applications should not be made in strong sunlight. 



Thrips tahaci does considerable damage to onions, grasses, garden 

 plants and also fruit trees. It is quite numerous on apple trees, on 

 the foliage and at the base of the fruit. Among trees kept under 

 observation, one that was not treated lost almost all its fruits, those that 

 were more than half developed falling, while in neighbouring trees 

 that were treated in time the fall of fruit was checked in a few days. 

 The leaves when punctured show small white marks and later turn 

 3'-ellow and wither. The remedy suggested is an emulsion ot 2 gals, 

 paraffin in 3 gals, water containing If lb. soap, to which is added 

 100 gals, of the tobacco decoction descril^ed above. 



FiGUEROA (C. S.). Mariposas perjudiciales. Las Polillas de la Papa. 



[Injurious Moths. The Pests of Potatoes.] — Serv. Policia Sanit. 

 Vej., Santiago de Chile, 1920, 10 pp., 6 figs. [Received 4th July 

 1921.] 



Two important potato pests in Chile are the Microlepidoptera, 

 Gelechia galbanclla, Z. [probably Phthcrimaea operctdella, Z.j which is 

 known in many countries as an enemy of the potato, and Trichotaphe 

 'tangolias, K. v. G.. which is a purely Chilian species, and more 

 abundant than the former. These two pests are increasing in 



