DISEASES OF CULTIVATED PLANTS 511 



hold. The specific cause of the disease is still in doubt, but it is 

 probably due to some form of vegetable parasite. 



As pointed out above, there are many conditions which bear an 

 important relation to foot-rot, and a brief discussion of some of 

 these will not be out of place, (a) Cattle-penning and pasturing, 

 so often resorted to for the purpose of fertilizing the groves, is, to say 

 the least, a questionable practice. The sharp hoofs of the animals 

 cut and bruise the bark on the crown roots, and thus, through their 

 agency, this possibly parasitic disease may be more rapidly carried 

 from affected to unaffected trees. Then, too, the rank manure may 

 act injuriously, and there is no doubt that there are better means 

 for supplying the requisite plant food than this. In fact, we believe 

 that the best orange is produced in Florida by the judicious use of 

 commercial fertilizers, (b) Close planting is often resorted to as a 

 means for shading the ground. A moist or damp condition of the 

 soil is produced about the tree, which, in our warm Florida climate, 

 is exactly suited to the development of disease. It would be de- 

 cidedly better to provide a surface mulch either by the growing of 

 leguminous crops or by providing a mulch of leaves and leaf-mold. 

 Air would then be freely admitted, and the sunlight, one of the 

 best germicides we have, would be allowed to reach the soil, (c) 

 The piling of rubbish, old tin cans, palmetto roots, etc., about the 

 trunks of trees is to be strongly condemned. Where a mulch of 

 leaves or grass is placed close to the trunks it should, from time to 

 time, be removed to allow the soil to dry out on the surface, (d) 

 Strict attention should be paid to drainage, that no stagnant water 

 be allowed among the trees. A soggy, ill-drained soil is not con- 

 ducive to the health of an orange tree. 



The remedies consist in removing, as far as possible, the detri- 

 mental conditions to which reference has just been made, and partic- 

 ular attention should be paid to everything conducive to the health 

 of the grove. Carefully remove the earth from about the tree, 

 avoiding injury to the healthy roots. With a sharp, strong knife, 

 cut out all the diseased tissues down to the healthy wood. Burn the 

 material removed. With a brush, paint the freshly cut wood, using 

 one of the following solutions : 



1. Carbolineum Avenarius.* 



2. Crude carbolic acid and water in equal parts. 



3. Sulphurous acid and water, three of the former to seventeen 

 of the latter. 



4. Lime, crude carbolic acid, and salt. Slake one peck of 

 lime in two gallons of water and add crude carbolic acid, four 

 ounces ; salt, three pounds. If too thick, add a little more water. 



Leave the earth removed until such time as the tree has recov- 

 ered, and then it would be better to fill in with fresh, porous earth. 

 In close-planted groves remove a sufficient number of trees to let the 

 light reach the ground. These can be set out in another plot of 

 ground. Disinfect cultivators, plows and harrows with carbolic acid 

 after using them in diseased groves, and before use among healthy 



*A fungicidal and insecticidal compound, used also as a wood preservative. 



