144 INSECTICIDES, FUNCxICIDES, AND WEED KILLERS. 



diseased plants to 7 per cent, whereas it was 100 per cent in the 

 unlimed plot. 



Plasnwdiophora Brasslca, Woronine (finger and toe). — Lime is 

 an excellent means of preventing the spread of this fungus. Nijpels 

 advises to mix the infected soil with half a litre of lime per square 

 metre. Seltensperger applies the following treatment; During and 

 after transplanting there is deposited at the foot of each cabbage in a 

 sort of deep cup, of 6-10 centimetres, made for the purpose, a big 

 handful of quicklime which is covered with earth to the level of the 

 surface. Of 600 cabbages and cauliflowers treated thus none were 

 attacked by the disease, whilst the untreated plot was seriously 

 compromised ; 25 per cent of the cauliflowers and 50 per cent of the 

 cabbages were attacked. Halstead who advises this treatment in 

 America believes that it has a preferable efl'ect on plants to that of 

 bouillie bordelaise, corrosive sublimate, blue vitriol, kainite, but it is 

 necessary to use at least 2 tons 8 cwt. per acre. 



Use of Lime against Nematodes. — Lime in strong doses is a 

 cure for these worms. Lime spread on the sui-face of the soil changes 

 its characters entirely. The humus (mould) sought after by these 

 worms being transformed the soil does not any longer present the 

 conditions essential to their growth. The evolution of the nematodes 

 is, moreover, arrested by the alkalinity of the soil. Although lime, 

 and especially quicklime, may disinfect the soil and thus improve 

 certain crops it cannot replace carbon disulphide, which according to 

 Girard destroys more surely all the nematodes in a field. 



Heterodera Schachtii, A. Schmidt (nematode of the beet). — Holl- 

 rung found this nematode very sensitive to the action of lime, and that 

 by mixing 1 part of quicklime with 4-6 parts of soil these nematodes, 

 were destroyed. Kuhn advises to apply the lime in autumn, as in 

 that way whilst diminishing the number of nematodes the lime trans- 

 forms the humus into assimilable matters and enables the more vigor- 

 ous beet to reconstitute its radicular system attacked by the parasite. 

 Tylenckus devastcUrix, Kuhn. — The liming of seed-corn is without 

 efi'ect against these, and disinfection does not diminish this disease as 

 the insects are polyphagous and even saprophytic. These insects live 

 on the most diverse plants, causing very difl"erent diseases, chiefly on 

 onions, clover, potatoes, poppies, etc. Weiss advises to burn the stems- 

 after harvest and dust the fields with quicklime and apply mineral 

 manure in abundance in the springtime. 



Use against Insects. — Few insects are sensitive to the alkaline 

 action of lime, yet those with soft skins and delicate larvte do na 

 resist milk of lime or powdered quicklime, which they particularly 

 dread. Lime thus forms an excellent medium for fighting these 

 parasites. But in most cases lime has only a mechanical action on 

 the spot occupied by the insect. 



Perroncito's experiments on the eggs of Bombyx Mori, L,, have 

 proved that milk of lime cannot kill the latter, for the eggs of this, 

 bombyx are capable of being perfectly hatched after steeping in 

 milk of lime for twenty-four hours. In spite of this harmlessness milk 

 of lime is used in arboriculture, for the liming of the trunks is an ex- 



