CALCIUM OXIDE (QUICKLIME). 143 



•5 per cent solution of soap. But the results were unsatisfactory. 

 The spores of Phytophthora mfestcms, De By. (potato disease) resist milk 

 of lime ; the latter is incapable of arresting the development of that 

 disease. Eust of wheat likewise resists the action of lime even in 

 heavy doses and in mixing it with equal parts of sulphur. 



Hitchcock and Carleton have, however, found that lime paralysed 

 the growth of the uredospores of Puccinia Buhigo vera, Wint. (rust of 

 wheat). But lime has no effect on Hypomyces perniciosus, Magnus, 

 mole disease of the mushroom. Used to combat the Guignardia 

 Bidivellii, Viala et Eavaz (black rot of the vine), lime gives fairly good 

 results. Galloway obtained by this method an appreciable diminution 

 of bad seed : on the untreated plot 45 per cent of diseased seed, on 

 the limed plot only 20 per cent of damaged grain. Debray also re- 

 gards the liming of the vine as a cure for Gleosporiuni amfelophagum, 

 Sacc. (grape rot), Botrytis cinerea, Pers. (the noble or grey rot of the 

 'vine). Sorauer advises to spread quicklime on the grapes in autumn 

 as soon as this mould appears. 



Qummosis of Stone Fruit Trees. — Sorauer advises to lime the 

 ground strongly around the trees attacked by this disease so as to 

 render the soil drier and warmer, an essential condition in counteract- 

 ing this disease. Wiesner regards this diseased condition of the trees 

 as due to the development of a special ferment, a species of diastase. 

 Be that as it may, a good result is obtained by spreading lime in the 

 autumn at the foot of the trees. If the trees in a moist soil suffer from 

 canker or rot of the roots, the roots must be stripped, lime spread 

 between them and the soil drained. This treatment leads to a per- 

 ceptible improvement in the diseased condition of the tree. 



Bhizoctinia violacea, Tul. (rhyzoctinia of the beet). — Frankel re- 

 commends to spread slaked lime in powder on the fields to diminish 

 the number of parasites. Here again lime only acts directly as on 

 mushrooms by changing the conditions favourable to their develop- 

 ment ; it arrests their growth and imparts to the plant by converting 

 the humus into assimilable matter the capacity to resist disease better. 

 Unfortunately it is alleged that lime, whilst it diminishes the amount 

 of these parasites, favours the development of other and not less 

 formidable beet diseases, e.g. Phoma tahifica, Prill, and Dela. (disease 

 of the petioles of beet leaves). The alkalinity of the medium in a wet 

 soil exei'ts a generally favourable influence on the development of the 

 bacterian diseases of plants. Wheeler, Tower, Tucker, and Sorauer 

 regard lime as favouring potato scab considerably. To reduce these 

 diseases it is on the contrary useful to render the medium acid, say by 

 green vitriol or by " sulpharine," which contains 15 per cent sulphuric 

 acid. 



Ophiobolus graminis, Sacc. (Pietin), (diseaseof wheat stalk). — Sance 

 advises as a cure to sow by hand 176 lb. of quicklime per acre as 

 soon as the disease appears. Marenghi recommends quicklime as a 

 preventive ; he advises to spread 3-4 cwt. per acre and to harrow the 

 ground slightly afterwards. 



Tobacco Leaf Spot. — Van Os to prevent this disease ploughs 

 in 11 bushels of quicklime per acre. He thus brought down the 



