Pomona College Journal of Economic Botany 



43 



of the acervuli on dead twigs and leaves, together with frequent brown 

 stains, "Tear-stains", on the fruit, further convinced them that our trouble 

 was the same. 



They were surprised that in the dry climate of California the fungus 

 could thrive and propagate itself so vigorously. Dr. Woods and Mr. Powell 

 both assured us that it could be checked by fungicides, particularly mentioning 

 Bordeaux Mixture with Bicarbonate of Soda, but they were of the opinion 

 that its present development in the orchard was probably abnormal, due 

 perhaps to extraordinary weather, for we had had a warm winter with more 

 than the average amount of humidity. With the return of dry summer 

 weather they thought it would make little or no further progress and probably 

 would cause no anxiety in the future except possibly during seasons similar 

 to the one just passed. Accordingly we did nothing at the time other than 

 to send samples of twigs, fruit, and leaves to Washington, together with a 

 request for all available literature on wither-tip, particularly Bulletin No. 

 52, by P. H. Rolfs, treating of the disease in Florida. The edition of this 

 bulletin was completely exhausted, but a later appeal to Dr. Woods, who 

 had returned to Washington in the meantime, brought the following reply : 



"Washington, D. C, May 29, 1909. 

 Mr. James D. Culbertson, Santa Paula, California. 



My dear Mr. Culbertson: I have your letter of May 21st. relative to your 

 failure to get the wither-tip bulletin. I was very sorry to find on my return 

 to Washington recently that this publication had been entirely exhausted 

 and that there was no copy to be had either from the department or from the 

 Superintendent of Public Documents. A new edition will have to be printed. 



Before leaving California I arranged with Mr. Powell to have a lot of 

 the lemons and grapefruits showing tear-stain and browning and other effects 

 of the wither-tip fungus forwarded to me. I had these very carefully ex- 

 amined and found the fungus, Colletotrichum gloeosporioides, present in 

 practically all cases. I explained to you, this fungus, which produces diseases 

 of various names, such as anthracnose, wither-tip, canker, lemon-spots, tear- 

 stain, etc., lives perennially in the twigs of the diseased trees. Infection of 

 the twigs is known to take place through the flowers, through injury to the 

 foliage, the fruit, and stems, by insects or otherwise. I think the red spider 

 is responsible for the spread of the fungus to a considerable extent on the 

 lemons this season, the slight injury produced by the spider making an 

 opening for the fungus to get into the skin of the fruit. 



(For control see same under that heading.) 



Very truly yours, 



A. F. Woods, 



Physiologist and Pathologist and Assistant Chief of Bureau. 



Through the courtesy of Mr. G. W. Hosford in investigating the careful 

 handling of lemons under the direction of Mr. Powell we obtained a few 

 days' use of a private copy of Bulletin No. 52 referred to above. A type- 

 written copy of this Bulletin put us in possession of sufficient data to direct 



