842 IOWA DEPARTMENT OF AGRICULTURE 



A summary of the diseases for the season of 1913, is as follows: 



The bitter rot, some reported from southwestern and central Iowa. It 

 is not, however, as common as the Illinois canker (Numyriularia discreta) 

 which is abundant in southern and southwestern Iowa, reported fre- 

 quently on the Ben Davis apple. Apple blotch {Phi/llosticta soUtaria) 

 though reported chiefly from southwestern Iowa, is common wherever 

 the Northwest Greening is cultivated. Little complaint was made of 

 the powdery mildew (PodospJidera leucotricha) . Apple scab {Venturia 

 inaequalis) was abundant in many parts of the state, especially on leaves 

 early in the season, though less in southern Iowa. Fruit was less scabby 

 this year than in seasons of greater moisture. Apple blight (Bacillus 

 amylovorus) was common in many parts of the state, though less than 

 in some seasons. Reported from various sections of the state by Prof. 

 Herrick on the Transcendent, Yellow Transparent, Wolf River, Tall man. 

 Apple rust reported on Wealthy, Jonathan, Ben Davis, Iowa Blush. The 

 Grimes Golden, though in proximity of infected red cedar, did not show 

 the disease according to Prof. Herrick at Red Oak. The period of in- 

 fection from the red cedar fungus was shorter than usual; some seasons 

 it extends over a period of a month. The gelatinous spore masses may 

 become dry and on becoming moistened the spores again germinate. 



Crown gall on blackberry was reported as serious in Scott county by 

 Mr. Bliss. It was also reported as serious on the apple in Page county. 



Pear blight occurred in some sections of the state. In Story county 

 there was much of the spot disease {Entomosporium maculatum) on the 

 leaves. Mr. J. P. Anderson reports considerable of Septoria pyrina in 

 Decatur county. 



Rust of blackberry (Gymnoconia Peckiana) was reported as trouble- 

 some in blackberry patches in several counties, probably widely dis- 

 tributed in the state. The custom of digging up the diseased plants 

 has done much to lessen the disease. 



Cherry spot (Cylindrosporium padi) occurred in central Iowa and 

 probably quite general in the state, most serious to nursery trees. It 

 was not common as during w-et years. 



Mildew {Podosphaera oxyacanthae) was widely distributed in the state 

 though not as abundant as in 1912. There was also much mildew 

 (MicrospJiaera alni) on the lilac, some on the oak. There was much 

 complaint of rose mildew (Sphaerotheca pannosa) on the Crimson 

 Rambler. The mildew on wheat (Erysiphe graminis) was not as abun- 

 dant as in 1912. The mildew on grape (Uncinula necator) was not as 

 common as in 1912. It was much more abundant on the Virginia creeper. 



Red currants were attacked by Cercospora angulata but not as serious 

 as in 1912. 



The downy mildews were not abundant this year, the grape was notably 

 free or nearly so except in northern Iowa. The lettuce mildew (Bremia 

 Lactucae) was abundant in greenhouses (Nevada) early in April during 

 the cloudy and misty weather, April 10-20. A few days of sunshine 

 checked the spread of the disease. There w^as less of the peppergfass 

 mildew- (Peronospora parasitica) this spring than in 1912. 



There was comparatively little of Sclerospora graminlcola on millet. 

 Potato blight (Phytopthora infestans) was not observed. It was- reported 



