ISl 

 INDIANA ri,ANT DISKASKS, r.H'O.' 



Max W. (iAKD.NKiJ.- 



Intkoductiox. 



lu accordance with the phiii outliiuMl in last year's report.^ tho plant dis- 

 caso situation in Indiana for the season of l!>li() is snunnarized heroin as 

 completely as our reports and observations permit. As in the previous 

 report, the economic point of view is maintained. 



Weathkk Conditions. 



The important relation of the weather to crop diseases warrants a brief 

 reiiort based upon the monthly summaries of Mr. J. H. Arminston of the 

 federal weather biu-eau at Indianapolis. 



The extremely cold, wet weather of April delayed farm operations and 

 retarded crops several weeks. The tirst half of May was also very cold. 

 culminating in frosts the 14th and lath which caused considerable injury 

 to fruit. In some localities seed potatoes rotted in the ground because of 

 the cold wet weather. 



The latter part of May and all of June and .Inly were in general favorable 

 to crops. June and July were exceptionally cool and rainfall was fairly 

 abundant. Severe hail injury occurred at Vincennes. June 1. at Madison, 

 June 14, and at Kokomo. Berne and Decker the 28rd. At Decker the in- 

 jury to corn, wheat, oats, tomatoes, melons, peaches and apples caused a 

 loss estimated at 150.000 dollars. 



August was also fairly cool and the whole summer up to the end of 

 August was characterized by the absence of any period of heat and 

 drouth. This type of weather greatly lessened the destructiveness of the 

 Fusarium soil diseases such as cabbiige yellows and favored the preva- 

 lence of such diseases as Septoria leaf-spot of tomato. 



September was very hot especially during the latter half with less rain- 

 fall than in previous years in central and northern Indiana and dry 

 warm weather continued well into October. This type of weather favored 

 the ripening of fall crops and at the same time was not especially conducive 

 to i)lant diseases. Light frosts occ\u-red October 20 and heavy frosts the 

 end of the month. 



In general the 1920 season was distinctly dilTerent from its itrede- 

 cossor and the difference in weather is r:ither strikingly retlected in the 

 plant di.sease conditions. 



'Contribution from the Botanical Dopartmont. Purdue Agricultural Exporimont 

 Station. Lafayette. Indiana. 



=The writer wishes to acknowledge the assistance of Prof. II. S. .Tackson. Mr. P. 

 .1. Pipal. Mr. G. N. Hoffer. Mr. .1. B. Kendrick. Dr. C. T. Gregory and I>r. E. B. 

 Mains of the Botanical Department and Messrs. C. L. Biirkholdcr. K. V. CulliiiMn. 

 F. C. Gaylord and H. D. BroWn of the Ilort i<-ultural Department of I'urdn.' Agikul- 

 tural Experiment Station. Most of the illustrations are taken from pliotograplis 

 made by Mr. Kendrick. ) 



''Gardner, Majc W. Indiana plant diseases, 1919. Proc. Ind. Acad. Sci. 1919, 

 in press. 



