1-2-2 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



sensitiveness of plants belonging to the Cypemceae and the reeds has 

 been often remarked, and this product is utilized to destroy them. Noffray 

 spreads wood ashes on meadows in wet weather or after a strong dew ; 

 the reeds and the rushes are burned and the leguminosue grow rapidly. 

 The injurious action of carbonate of potash is not limited to these 

 plants alone, it is very decisive on dodders, mosses, and lichens. 

 The first are destroyed by spreading wood ashes on the clover fields 

 in dry weather and watering afterwards. The result is satisfactory, 

 but it cannot be compared to that got with green vitriol, for there often 

 remains after treatment some immune parts which contribute to the 

 propagation of the disease. Carbonate of potash may replace lime 

 against mosses and lichens. Sorauer replaces the common process of 

 liming the trunks of trees by coating them with a solution of 15 lb. of 

 carbonate of potash in 15 gallons of water. This treatment not only 

 frees the tree from the parasites sheltered under the fissures of the 

 bark but does not colour the tree white like lime. 



Action on Fungi. — Alkaline carbonates have no toxic action on 

 spores of fungi, but at a certain strength they impede their growth. 

 Tillet who observed this action found it sufficient to guarantee the 

 seeds of black wheat. Disinfection by the lye from wood ashes lias 

 given appreciable results. 



PlasmodiopJiora Brassicce, Woronine (finger and toe). — As a pre- 

 ventive, Nijpels waters with carbonate of potash against the finger 

 and toe so as to kill the spores of the myxomycetes and prevent infec- 

 tion of young plants. 



Action on Insects. — Soft-skinned insects are generally very 

 sensitive to alkaline substances and may be combated therewith. 

 Soft soap and lime are of great service ; carbonate of potash acting 

 similarly has been recommended by some observers. 



Crioceris Asparagi, L. (the asparagus beetle). — The larva3 of 

 this Coleoptera is very delicate and may be destroyed by spraying 

 with the lye from wood ashes. 



Haltica (ground flea beetle). — To prevent these voracious Coleoptera 

 from gnawing the young plants growing in the fields in the spring, 

 Montillot spreads wood ashes on the seed beds. It is chiefly against 

 the different species of plant lice that carbonate of potash has been 

 found useful. 



Schizoueura Lanujera, Hausm. (the woolly aphis or American 

 blight). — Taschenberg uses lye from wood ashes to destroy this insect, 

 but Muhlberg found this method ineffective. 



Phylloxera vastatrix, Planch. — Mouillefert found potassium carbon- 

 ate ineffective. 



Aspidiotiis p)erniciosa (San Jose louse). — Marlatt made numerous 

 attempts to destroy this apple bug so formidable in America, and ob- 

 tained with 24 lb. of lye in 10 gallons of water, 85 per cent lice killed ; 

 with 12 lb. 75 per cent ; with 6 lb. 50 per cent ; with 3 lb. 20 per cent. 

 Carbonate of potash in itself acts injuriously on the lice, and as it is at 

 every one's disposal it may be tried in certain cases. But it will act 

 more surely if it be used as an aid to certain toxic substances, 

 petroleum, for example. Alkaline products, in fact, act on the mucus 



