E. J. BUTLER 



23 



at the end of November, 1913. 3-12-'13, the stubble was cut and the plot re-sown, 

 some infected stubble being returned after sowing. Further details are given 

 under Experimoiit III on p. 20 above. Ufra was well developed in July, 1914, 

 and the photograph reproduced in Fig. 4 was taken on August 21st. On August 



Fig. 4. Condition of the centre plot of Experiment IX on Aug. 21st, 1914. 



26th the crop was burnt on the ground with kerosene oil and a fresh crop (both 

 transplanted and broadcasted) put in on August 29th. This grew well and headed 

 out normally in November with no trace of uiia,. 

 X. Four plots were sown with jjaddy on May 24th and 25th, 1915. 28-7-' 15, two of 

 the plots were inoculated by placing fresh diseased shoots (4 days old) in the 

 water. 15-8-'15, a few plants showed symptoms and were found infected w'th 

 worms. 8-ll-'15, the disease now well developed, almost all the plants being 

 attacked in one plot, while the other contained numerous scattered eases. The 

 soil of the latter was rather porous and the water-supply not well maintained on 

 its surface. It ripened a moderate crop in December and was allowed to shed 

 its grain, which germinated as mentioned above in Experiment II on p. 20. A 

 permanent supply of water was arranged from July, 1910, previous to which it 

 had been only watered intermittently. Ufra aj)pearcd in July, 1916, scattered 

 plants showing chlorosed shoots without brown stains. One was examined and 

 found infested with Tylenchus angustus. 22-11 -'10, a good many jjlants had now 

 well-marked ufra and were heavily infested. Li the other plot the disease had 

 been so severe the previous year that there was little grain produced and the 

 self-sown plants were very few. 26-7-' 10, transplanted a number of seedlings 

 into this plot, but did not rmi in any water, so that the soil remained dry except 

 when wetted by rain. There were some early signs of ufra in the self-sown plants 

 in July, but the attack did not develop further and when harvested there was no 

 evident disease and no trace of worms could be found in a large number of plants 

 examined. The other two (uninoculated) plots remained healthy throughout. 

 Here it would seem that standing water or at least a permanently wet soil ia 



