INFLUENCE OF CULTURAL CONDITIONS. 47 



From a careful study of Table VIII it is quite evident that no 

 single cultural factor will be found to explain the varying mortality. 

 The character of the soil in each group varies from sandy postoak to 

 black river bottom. The direction of the rows fails to show any con- 

 sistent relationship to the proportion of weevil stages destroyed. 

 The condition of cultivation was recorded for but few fields, and may 

 practically be disregarded because of the lack of data. In the column 

 for spacing of plants among the remarks are some points which were 

 undoubtedly influential in producing the mortality results shown. 

 Table VIII should be studied in connection with Table VII. At 

 Beeville it was noted, that the stand was poor and that only one-half 

 of the ground was shaded where the stand was good. A large propor- 

 tion of the squares were infested as early as July 12, and fallen, 

 drying squares were abundant on the ground. Referring to Table 

 VII in connection with Table VIII, it will be seen that under these 

 conditions, with only fallen squares and bolls examined, the mor- 

 tality from heat was quite large, but that caused by ants was 

 relatively more than three times as great. Had the ants not been so 

 active, it is very likely that the percentage of mortality from heat 

 would have been very much greater. As it was, so many weevil 

 stages were destroyed by the ants soon after the forms had fallen 

 that the mortality from heat was kept comparatively low. 



At Beeville about the middle of July the cultural notes indicate 

 that the stand was uneven and that at best only about one-half of 

 the ground was shaded. During July and August the climatic records 

 show that the temperature averaged 1.5 degrees below normal, while 

 the rainfall amounted to 1.42 inches above normal. Doubtless the 

 excess of rainfall and the deficiency of heat are correlated. Under 

 these conditions, however, there occurs the highest total mortality 

 found in any locality, i. e., 84 per cent. Of this total mortality heat 

 and drying was responsible for 20 per cent, while ants destroyed 62.8 

 per cent. In this case, therefore, it is evident that the ants were far 

 the most important factor in producing the highest recorded per- 

 centage in mortality, and it would appear that their work was favored 

 by the conditions of open spacing, medium heat, and much moisture. 



At Overton the ants caused an even greater proportion of the total 

 mortality than is shown above for Beeville. At San Antonio the 

 examinations were not extensive, but the ants were responsible for 

 the entire mortality found. In these three cases of highest total 

 mortality the climatic factors would seem to have been much less 

 important than was the abundance of the ants, which might have been 

 influenced by local conditions. 



At Corpus Christi all of the examinations were made 1 on July 10. 

 The notes show that at that time the ground was about two-fifths 



