Apple rust . sible to detect any air 20 W. Va. Agrl. Experiment Station [Bul. 154] stirring during the afternoon. It should be noted that theseapple trees were within ten rods of large cedars which wereliterally loaded with rust galls. It rained again during the night of May 14th-15th, andthere was abundant sporidia discharge from about 10 A. 2 P. M. of the 15th. The only serious rust infection forthe season of 1913 occurred at this time. There was a lightwind and it was somewhat variable. The humidity gradually dropped about 15% during theperiod of the most active sporidia discharge on M
Apple rust . sible to detect any air 20 W. Va. Agrl. Experiment Station [Bul. 154] stirring during the afternoon. It should be noted that theseapple trees were within ten rods of large cedars which wereliterally loaded with rust galls. It rained again during the night of May 14th-15th, andthere was abundant sporidia discharge from about 10 A. 2 P. M. of the 15th. The only serious rust infection forthe season of 1913 occurred at this time. There was a lightwind and it was somewhat variable. The humidity gradually dropped about 15% during theperiod of the most active sporidia discharge on May 14th,and there was a slight raise in temperature during that data may be noted on the chart for May 15th, exceptthat the drop in humidity was considerably greater and therise in temperature was more pronounced than on the previousday. A section of chart showing tracings for May 14th and15th, 1913, is shown below: TUESDAY WBDNESDAY THURSDAY FRII temperature: hour lines indicated in top margin. HUMIDITY HOUR LINES INDICATED IN BOTTOM. MARGIN Hygrothermograph record from Tuesday, May 13th to Friday, May 16th, 1913. Rain occurred again on May 17th, but there was no evi-dence of infection following it. Twigs which had previouslybeen sacked and were uncovered on the 16th were as wellprotected as those uncovered on the 19th. The humidity and [Aug., 1915] Apple Rust 21 temperature conditions would appear to have been very goodfor sporidia discharge, but we have no records as to airmovements. It is possible that many sporidia were set freeand that they settled quickly to the ground as on May 14th,but it is far more likely that only a very few were discharged,since the sori on the cedar galls were much reduced in sizeand evidently becoming exhausted. Careful observations asto actual spore discharge were not made on this date. of chart for May 17th and 18th is given below: FRIDAY TEMP ERATUR E SATURDAY SUNDAY MOUBJ. HOUR LINES INDICATED IN TOP MARGIN
Size: 1934px × 1292px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidapplerust154, bookyear1915
