NOTES ON PLANT DISEASES OF CONNECTICUT. 735 



RYE, Secale cereale. 



POWDERY MILDEW, Erysiphe graminis DC. In our Report 

 for 1903 we listed the conidial stage of this mildew on cultivated 

 barley. In 1910 specimens on rye were received from J. F. 

 Shepard, of New Haven, and others were collected by the writer 

 at the station farm at Centerville, these being the first collections 

 on this host in the state. In the latter locality the perithecial 

 stage was very conspicuous and abundant on rye, but on barley 

 was practically absent. Considerable injury was caused to both 

 these hosts through severe infection of the leaves, which died 

 prematurely. Apparently the season was favorable for an 

 unusual development of the fungus. It forms an evident 

 grayish felt in small clusters, thickly covering the leaves, and 

 the perithecia, when produced, show as small but evident black 

 specks embedded in this. As usual with this species, none of 

 the asci matured their spores on the living plants. 



SQUASH, Cucurbita Pepo. 



Chlorosis. In previous Reports we have mentioned chlorosis 

 troubles of Lima and string beans, muskmelon, tobacco and 

 tomato. Of these so far we have been able to prove only those 

 of tobacco and tomato to be infectious, that is, capable of 

 producing the trouble in healthy plants when juice from the 

 chlorosis plants is placed on the young leaves. In June, 1910, 

 we saw plants of summer squash in cold frames at the Farnham 

 farm in Westville that were subject to a chlorosis trouble, 

 though from its appearance it did not impress us as being 

 of an infectious nature. The leaves were quite prominently 

 streaked with irregular areas of lighter yellowish-green, the 

 normal green color remaining more commonly around the veins. 

 The cause of the trouble was not determined, though possibly 

 too much manure in the beds may have had something to do 

 with it. 



SWEET PEA, Lathyrus odoratus. 



POWDERY MILDEW, Erysiphe Polygoni DC. Previous to this 

 we have reported in this state only one trouble of the sweet pea ; 

 viz., a rot disease. This powdery mildew forms a mealy, whitish 

 growth on the leaves through the production of its conidial 

 stage, but the perithecial stage was not found. Apparently the 



