150 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



Cuscuta (dodder). — Carrigon employs calcium sulphide with suc- 

 cess to destroy dodder in forty-eight hours. To obtain this effect 

 calcium sulphide is spread on the ravaged parts of the field, and these 

 spots sprayed slightly with water. The result is especially favour- 

 able in wet weather. If this treatment is applied before the maturity 

 of the grain the dodder may be considered as eliminated from the 

 fields. 



Pero7ios])ora viticold, De By. (mildew of the vine). — Vesque re- 

 commends polysulphides against this parasite of the vine. A bouillie 

 is prepared for the purpose with 1 lb. of quicklime to 3 lb. of sulphur 

 in 10 gallons of water. The leaves and the grapes are sprayed at the 

 time the vine is usually sulphured. 



Enjsiphece (mildews). — All these fungi can be destroyed by calcium 

 sulphides ; they act on their mycelium disorganizing them rapidly like 

 sulphur. Their use is, however, more simple, their action more 

 regular, because it does not depend on the temperature which, as 

 regards sulphur, is one of the conditions of success. Besides, solutions 

 being spread more uniformly on the organs of the plant attacked 

 the action is more thorough. 



Uncinnla Americana, How. (oidium of the vine). — Crouzel re- 

 commends his " anticryptogamic " against the oidium, the composition 

 of which has already been given. Spraying ought to alternate at 

 five or six days' interval with cupric preparations. Polysulphides em- 

 ployed without naphthalene or hyposulphite produce the same effect, 

 and Mohr's preparation arrests the oidium in full evolution. In the 

 spring 4 per cent solutions of polysulphides are used, 5 per cent 

 solutions after flowering, and 6 per cent solutions at the end of summer. 

 The latter do not injure the leaves. In the same way as for the 

 oidium, mildew of the vine, the polysulphides of calcium have been 

 used to destroy the following Erysvphea (mildews) : SpharotJieca 

 pannosa (mildew of the rose and the peach) ; MicrosjjJicera Gross ularice, 

 Wall, (mildew of the gooseberry) ; Erysij)]te communis, Wall, (mildew 

 of hay and clover). Nijpels recommends to use against mildew of 

 the rose a sulphide prepared thus : boil 100 gallons milk of lime 

 made with 20 lb. of quicklime and 40 lb. of sulphur; after twenty 

 minutes' boiling the sulphur is dissolved and the whole cooled. A 

 teaspoonful of this solution per litre of water for spraying suffices, 

 which should be done two or three times during summer. 



Capnodium (fumagine). — The fumagine (fruit tree smut) is destroyed 

 by 5 per cent sulphide solutions, but according to Franck and Kruger 

 this product cannot destroy the cochineals whicli produce it. 



Amongst the black-blights there are also some which may be com- 

 bated with polysulphides : Gloeosporium arnpelophagum^ Sacc. (an- 

 thracnose of the vine). Against this disease it is necessary to apply a 

 spraying of sulphide before the flowering of the vine. 



Cladosporium fulvum, Cooke (tomato disease). — Mohr particularly 

 advises the use of polysulphides against this disease which act in a 

 more efficient manner than copper salts. 



Actinonema Rosece, Fr. syn. (Asteroma radiosium, Fr.). — Mohr re- 

 commends two or three sprayings during summer. 



