302 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



served that this practice succeeded in freeing strawberries from the 

 strawberry anthonome {Anthononiua rubi, Hbst.). 



Scolytifhe (scolytides). — Winter treatment of trees by the petroleum 

 emulsions destroys both Xylophagus insects which live in burrows dug 

 in the bark of the trees, or immediately underneath it. F. H. Chit- 

 tenden recommends this treatment especially acjainst Scoli/tiis rtigu- 

 losus, Eatz. (scolytus of fruit-trees). 



Chrysomelince (chrysomelines). — These may be destroyed by 

 petroleum emulsions, especially if hellebore or quassia extracts be in- 

 corporated therewith. Comstock, Slingerland, Smith, and Von Schilling 

 recommend the use of soapy emulsions as effective against Crioceriis 

 Asparayi and PhcBclon armoracue, L. (chrysomelide of the radish), 

 (cochlearia). They destroy the larvte. 



HalticincB (altises). — Petroleum is very useful in destroying them, 

 and its good effects on a large number of species have been recorded, 

 viz. : Haltica oleracea, L. ; Phyllotreta nigripes, F. ; rhyllotreta 

 sinuata, Steph.; Phyllotreta undulata, Kutsch.; Phyllotreta nemorium, 

 L., injurious to the cruciferae ; Psylliodes affinis, Payk., injurious to the 

 potato; Haltica rittula, 'Redt., injurious to ci2rea,U; Haltica rufi pes L., 

 injurious to peas and haricots. In the same way as the individual altises 

 whose sensitiveness to petroleum has been the object of the above 

 special observations, all altises in general are killed by petroleum. 

 Care must be taken not to use too concentrated emulsions so as to 

 safeguard the plant invaded by the ravisher and only use perfectly 

 homogeneous preparations. This point is much more important, as 

 the organs sought after by the altises are the most tender part of the 

 plant, aud, consequently, the most sensitive to the action of petroleum. 

 Eitzema Bos advises to get rid of altises the use of an intimate mix- 

 ture of 4 litres of petroleum and 16 litres of sand for 100 square 

 metres of soil. Used on the spot invaded by the earth-lice, it is found 

 that they immediately quit the plots ti-eated and do not return until 

 ten to fifteen days later. This method gets quit of altises when the 

 plant is small and much exposed to complete destruction by the altise. 

 Comstock, Slingerland, and Lampa advise the use of emulsions with 

 quassia extract for the same purpose. Petroleum and soap emulsions 

 are perfectly capable of being of service to agriculturists as destructors 

 of Coleoptera, especially when it is a question of their larvte. In any 

 case, the smell of petroleum is so objectionable that those not touched 

 by it desert the plant treated. Smith, Lintnei-, and Foi'bes have shown 

 that the eggs of the insects have such a resistance that a 80 per cent 

 emulsion of ])etroleum does not kill them. 



Use against liyinenoptera. — Lophyrus Pini, Lopihyrus rufus 

 (the pine saw-fly). — Eitzema Bos advises petroleum emulsions to 

 destroy the larvue of these lophyres. Their larvse are very sensitive, 

 especially when young. The treatment does not injure the pines. 



Nematus Bihesii (nematode of the gooseberry), (gooseberry saw-fly). 

 — According to Johnson the young larvae are killed by a 1'2 per cent 

 emuls on, the adults by the same emulsion containing 0-6 per cent of 

 hellebore decoction. 



Use against Lepidoptera. — Lepidopterous caterpillars are gener- 



