362 EXPERIMENT STATION RECORD. 



attention to the serious decrease in yield of encumbers for the season 

 of ISilT. The principal cause of this diminished yield is attributed to 

 attacks of the downy mildew (Plasmopara cubensis) and the anthrac- 

 nose (Colletotrichum lagenarium). Of these the downy mildew was the 

 more destructive. The history and distribution of both these diseases 

 is given. They are reported as having been observed in 10 States. 



An experiment was conducted under the author's direction for the 

 prevention of the downy mildew by 2 applications of Bordeaux mixture. 

 Comparing the yields of sprayed and unsprayed rows, it was found 

 that 25 sprayed rows yielded 51 bu. of cucumbers, while an equal num- 

 ber of unsprayed rows gave 38.4 bu. The cost of spraying seems 

 unnecessarily high and could probably have been considerably reduced. 

 Suggestions are given for the planting of cucumbers, allowing for road- 

 ways, so that power sprayers may be used. 



The leaf blight of melons, due to Altenaria sp., which was described 

 and figured in Bulletin 73 of the station (E. S. R., 8, p. 991), has again 

 proved quite destructive during the season of 1897, and has extended 

 its attacks to watermelon leaves. The muskmelon leaves, however, 

 showed the earliest symptoms, dying off rapidly, with the characteristic 

 spotting. 



Notes are given on the tomato leaf blight fungus (Scptoria lyeopersid), 

 which seems to have become well established throughout most of the 

 State. It may be successfully prevented by the thorough use of Bor- 

 deaux mixture. 



An experiment was conducted in which seeds were treated with cop- 

 per sulphate solution and with hot water, to ascertain the effect of 

 such treatment on the invention f the tomato anthracnose. Soak- 

 ing the seeds 1 and 2 hours in 10 per cent solution of copper sulphate 

 or immersion for 5 minutes in water heated to 133° did no injury to the 

 germination. The absence of all traces of diseases in these trials pre- 

 vented any conclusions relative to the treatment of the disease. 



Plant diseases in Java. M. Racikorski {Ztschr. Pflanzenkranh, 

 8 (1898), No. 2, pp. 66, 67). — The author reports the existence in Java 

 of 2 undescribed diseases of the cowpea and the peanut. The fungi 

 attack the leaves of their respective hosts and have both proved very 

 destructive. 



The disease of the cowpea is caused by Ccrcospora vignce. On the 

 upper surface of the leaves it produces rounded or somewhat irregular 

 spots 0.5 to 2 cm. in diameter. These spots often coalesce and the tis- 

 sue becomes dead. On the under side of the leaves the spots are 

 brownish gray, and after the formation of the spores they become 

 dark rusty gray. The spots are not bordered. The mycelium is 

 found about the fibro-vascular bundles and in the spongy parenchyma, 

 but it does not send haustoria into the cells. The conidiophores are 

 borne upon the under side of the leaves. The conidia are 3.5 to 5 /a in 

 diameter and are very slender. The small ones measure 20 /< in 



