Pomona College Journal of Economic Botany 



39 



perfectly sound and in excellent condition. The occurence of the trouble 

 is sufficiently great to warrant considerable expense in preventing it. 



literature and synonymy 



Collet otrichum gloeosporioides Penzig. 

 Vermicularia gloeosporioides, Penz. Funghi Agrumicoli. No. 90, p. 66, Padova, 



1882. 



Phyllosticta adusta, E. & M. Jour. Mycol. II, p. 130, Nov., 1886. 

 Colletotrichum gloeosporioides Penz. Botanici rumi e sulle piante affini, Ann. 



d'Agris, p. 384, 1887. 

 adustum E. Jour. Mycol. VV, p. 35, May, 1891. 

 gloeosporioides Rolfs. U. S. Dept. Agrcl. B. of PI. Ind., Bull. 

 No. 52, Mar., 1904. 

 Hume. Fla. Agrcl. Exp.. Sta. Bull. No. 74, 

 Aug. 1904. 



Rolfs. Fla. Agriculturalist. 32, p. 130, Mar. 

 1905. 



Hume Cirt. Fruits and Their Cult. pp. 473- 



475, Dec. 1907. 

 Duggar. Fung. Dis. of Plants, p. 327-328, 1909. 

 Cal. Cul. 32, p. 708, June 1909. 

 Cook. Cal. Cul. 33, p. 460. Nov. 1909. 

 Fawcett, Fla. Agrcl. Exp. Sta. Press Bull. No. 



133, Dec. 1909. 

 Massee. Dis. of Cul. Pis. and Trees, p. 144, 



Jan. 1910. 



Fawcett, Cal. Cul. 34, p. 725, June 1910. 

 Cal. Cul. Pruning 35, pp. 660-661, Dec. 1910. 



CONDITIONS FAVORABLE TO GROWTH 



Any climatic condition unfavorable to the growth of the tree is liable 

 to bring on an attack of wither-tip, especially in a country which has been 

 subject to this attack. 



Frosts kill the twigs of the trees and afford excellent places for the fungus 

 to germinate and produce spores. 



Wind. — Hard winds whip the trees so as to cause numerous abrasions 

 and wounds, which afford excellent entrances to the spores of the wither-tip. 



Insects. — Perhaps no better condition is afforded for the infection of the 

 plant tissues than that due to the attacks of insects. Scale pests constantly 

 draw sap from the trees, and the slightest rain washes the spores down the 

 limbs and into their punctures. It might be expected that this disease would 

 be worse in dirty orchards than in those which are kept perfectly clean. 



Diseases. — Gummosis has certainly had something to do with the production 

 of the "red spot" so often referred to. As has been stated, the two condi- 

 tions have been associated together as arising from a common cause. The 



