124 STATE BOARD OF AaRICULTURE 



been carried on nnder this head. The reports of plant disease occur- 

 rence, etc., have been made to the central, federal office. 



State Projects: 



Celery Disease Investigations. 



Work on celery diseases has confined itself to development of the 

 3'ellow-resistant celery. Some 400 plants of known parentage were tested 

 in the field and found resistant to the disease. These plants were brought 

 through the winter in the greenhouse and are now producing seed. 

 Progenies from the original selection made in 1919 are now being tested 

 as to quality and type. From this set of plants will be selected the best 

 commercial strain, and then the seed will be released through the ordi- 

 nary channels for general use. The work is handicapped by lack of 

 greenhouse facilities and much valuable time in the increase of seed stock 

 is being lost. For three years the yellow-resistant seed has produced 

 fine plants in disease-infested soil eitlier at Kalamazoo or Mason, Michi- 

 gan. 



Bean Disease Investigations: 



Investigation of bean diseases has been restricted to two lines of 

 work: (a) work of testing of bean hybrids for Anthracnose resistance, 

 and (b) investigations of Bean Mosaic. 



(a) The first line of work has been carried out in co-operation with 

 the Farm Crops Department and consists of testing various new strains 

 of beans derived by crossing Red Kidney beans (Wells) with Robust 

 beans. These have been subjected in field and greenhouse to various 

 strains of Bean Anthracnose and all those proving susceptible to attack 

 have been rejected. About a dozen beans of very resistant type are now 

 being studied by the Crops Department for yield and the tests with 

 organisms are being continued. This work is carried on by the writer. 



(b) The other phase of bean disease investigations carried on at the 

 station consists in work on Bean Mosaic by Ray Nelson. In this work 

 Mr. Nelson has sought to throw some light on the cause of mosaics — 

 those obscure diseases about which there is so much that is unknown 

 and baffling. By cytological investigations, Mr. Nelson found certain 

 heavily staining bodies in the phloem of diseased plants and he inter- 

 preted these to be protozoa, presumably the casual agents in disease 

 production. Further work with other plants than beans has failed, so 

 far, to confirm this interpretation and more work is needed to clear 

 up this problem. Mr. Nelson has been on a year's leave of absence 

 working for an advanced degree at the University of Michigan. 



Potato Disease Investigations : 



This work has, as in the past, consisted of certain field trials carried 

 on jointly by Mr. J. E. Kotila and the undersigned and in investigations 

 of the black-leg disease carried on by Mr. Kotila. 



Experimental fields have largely been located at the Upper Peninsula 

 Experiment Station at Chatham, where interesting results on the use 

 of sulphur for Scab control have been obtained. In field tests the 

 relative values of spraying and dusting for hopper burn and fungous 

 disease control have shown marked superiority of tiie Bordeaux spray. 



In co-operative work with the Farm Crops Department hundreds of 



