53 



limoni; 1 the body of this fungus consists of very slender, colorless 

 threads which are divided by frequent transverse partitions or septa. 

 The threads are found in all parts of the diseased tissues and in the 

 process of growth they give rise to numerous compact tufts of erect 

 branches upon the free ends of which are developed crescent shaped 

 spores or reproductive bodies; the latter are produced in prodigious 

 numbers and germinate readily in water or moist air. Referring to the 

 Ftisarinm, Briosi says: 



It is not certainly known what connection tliis fungus lias with the disease under 

 consideration. Whether it should he placed among the causes or he considered a 

 simple incident of the malady are questions that remain to he answered. * * * I 

 do not think there is any doubt, however, that its presence generally accelerates the 

 disorganization of the tissues. 



In the Florida specimens which have been examined we have failed 

 to find the fungus described by Briosi; but in the Department green- 

 houses there is a fungus on the diseased trees which resembles Briosi's 

 figures, and is probably the same as the one found by him. Many 

 theories have been advanced as to what extent the nature of the soil, 

 method of culture, manner of setting the trees, kind of manure used, 

 etc., influences the disease, but these are so conflicting that it is diffi- 

 cult to draw any practical conclusions from them. Those who have 

 given the matter careful study agree in saying that heavy manuring, 

 an excess of water in the soil, and frequent cultivation favors the de- 

 velopment of the disease. 2 



IV. Treatment. 



From all the evidence at hand it appears that the only safe means 

 of preventing or checking the ravages of the malady are, (1.) to bud at 

 least 3 feet above the ground on resistant stocks, 3 (2) to plant on dry or 

 porous soil, (3) to irrigate sparingly, (4) to use the knife freely when- 

 ever the malady appears, and burn or destroy all diseased wood. 



V. Bibliography. 1 



AsJimead : Foot- rot, Sore shin, or Gum disease; Bulletin No. 2, Florida Agricultural 

 Experiment Station, 1888. 



Briosi: II male di gomma negli Agrumi, Botter, Giorn. d'Agricolt., Ser. K, anno 

 III, vol. VI, n. 19, 20, 21. 



1 Fusarium limoni, Briosi. (Penzig Aunali di Agricoltura; p. 422; 1887). — Acervuli 

 gregarious, confluent, white; hyphse spreading, septate ; conidiophores erect or as- 

 cending, with alternate or opposite branchlets; conidia very variable, acrogeaous, 

 continuous or septate in the middle, or hi-triseptate, oblong or fusiform, slightly 

 curved, attenuated, slightly constricted at the septa, hyaline, 26-27 fi long, 2,4-2,8 /ii 

 in diameter. 



2 Sorauer affirms that the disease is promoted by the cultivation of such crops as 

 beans, pumpkins, tomatoes, etc., between the trees. He also states that analyses of 

 healthy, dead, and diseased trees show the latter to contain less phosphoric acid and 

 iron. 



3 In Florida it is claimed that sweet seedlings are especially liable to the attacks of 

 foot-rot, while all other stocks are practically resistant. 



4 Only some of the more important papers are here noted. 



