19-2 INSF.CTICIDES, FUNGICIDES, AND WEED KILLERS. 



Peronospora riticola, De By. (mildew of the vine). — Ch. Truchot 

 recommends a permanganate solution of 0-125 per cent against mildew. 

 Tried in the Canton of Vaiid in Switzerland it sometimes gave excel- 

 lent, sometimes negative results. It is otherwise with a mixture of 

 houillie hordelaise and permanganate of potash. Guocdenovic made 

 up bouillies containing 0*75 per cent, 0-5 per cent, 025 per cent of 

 blue vitriol and O'l per cent of permanganate of potash. Compared 

 against ordinary bouillie bordelaise these permanganate bouillies gave 

 better results even when they only contained 025 per cent of blue 

 vitriol and 0"1 per cent of permanganate of potash. This mixture 

 whilst giving excellent results effects great saving in copper. The 

 permanganated bouillie bordelaise behaves both like bouillie bordelaise 

 and as blue vitriol, that is to say, it possesses, along with the reserve 

 of copper to prevent the invasion of the mildew and prolong the action 

 of the bouillie remaining on the leaves, a very active substance having 

 an immediate deadly action on the exterior organs of these fungi, the 

 conidiophores. This bouillie gives good I'esults when it is a case of 

 arresting a sudden invasion during a moist warm period of summer. 

 However, permanganate alone does not suffice to contend against this 

 disease, for it has only a curative action and is entirely deprived of pre- 

 servative effect. It is therefore necessary to multiply the treatments an 

 infinite number of times w^ith permanganate alone to get a result ana- 

 logous to that obtained with cupric bouillies or permanganated cupric 

 bouillies. 



Disinfection of Trees. — It has been recommended to coat fruit 

 trees in the spring when the buds are barely formed with an 0"125 

 per cent solution ; it is even recommended to spray the whole trees 

 with this solution after flowering. The results were very satisfactory. 



Botrytis Douglasii, V. Tub. (conifer disease).- — The rot of conifers 

 produced by Botrytis cinerea, Pers., has been combated by Van Bier- 

 vliet by making sprayings with a bouillie consisting of — 



Copper sulphate 700 oz. 



Carbonate of copper i:-5(50 ,, 



Permanganate of potash >^-'J ,, 



Soft soap 22') ., 



Rain water -jOU trillions. 



Nemaloides. — Humphrey got excellent laboratory results against 

 the nematoides of the violet by frequently spraying with a 0'05 per 

 cent solution. The experiments on the large scale, however, did not 

 succeed. 



76. Manganese Sulphate, MnSO^SHoO. — Preparation. — By 

 dissolving manganese in sulphuric acid. 



Properties. — The same as green vitriol. 



Action of Manganese Salts on Plants, — The action of manganese 

 salts on plants has l:)een examined chiefly in Japan. The experiments of 

 Loew and Honda to determine the action of sulphate of manganese on 

 the growih of Cryjdonicria japonica have shown that manganese salts 

 possess like copper and other analogous salts the property of stimulat- 

 ing the growth of the plant and in that way increasing the yield of the 

 crop. The yield in their case was 646 7 grammes against 316-9 



