6 BULLETIN 1153, U. S. DEPARTMENT OF AGRICULTURE. 



even on plants that stood only a few feet away from the heavily 

 infested fields or experimental plats that had grown into boll-weevil 

 cotton. (PI. Ill, Fig. 1.) Some of the plants that had been isolated 

 rather late in the season by root-rot killing their neighbors were 

 still producing numerous young bolls in October, notwithstanding 

 the large weevil population close at hand. These productive plants 

 were in striking contrast to the barren boll-weevil cotton only a 

 few feet away, where scarcely any late bolls were to be found 

 except occasional bolls on drooping lower branches, which the weevils 

 seem to neglect or fail to find. 



A count of bolls on one of the isolated plants on October 19 gave 

 a total of 44, including several that had opened recently and 18 

 that were still green. Thus there could be no doubt that regular 

 fruiting had continued on this isolated plant, while other plants in 

 the same field averaged less than five bolls apiece, often only one or 

 two bolls, and most of these confined to lower branches and produced 

 early in the season. On 12 plants that were nearest to this isolated 

 individual with 44 bolls, the following numbers of bolls were 

 counted: 7. 4, 7, 1, 4, 3, 3, 2, 6, 4, 9, 7. But some of these were end 

 plants and their partial exposure may have given advantages over 

 the regular run of plants in the rows. 



A similar advantage from better exposure was apparent in the 

 outside rows of a field that was bordered on the south side by an 

 orchard of pomegranates (PL I, Fig. 2). This field was planted 

 late and did not have the advantage of setting bolls during the short 

 period of favorable conditions earlier in the season, when bolls had 

 been set on earlier plantings. Thus, the late-planted field was an 

 almost complete failure, yielding scarcely a boll per plant except on 

 the rows along the pomegranate orchard. On account of the smaller 

 size of the plants, which may be ascribed to competition with the 

 pomegranates, these outside rows did not close the intervening lanes 

 or shade the ground continuously and suffered notably less from the 

 weevils than the remainder of the field, which grew into regular 

 boll-weevil cotton. Late in the season the advantage was shown very 

 definitely in the numerous green bolls that were still developing on 

 the small, open rows, while no fruit was being set in other parts of 

 the field. Although the outside row had the smallest plants, it 

 yielded 8 pounds 15 ounces of seed cotton, or nearly twice as much 

 as the next row. which produced 4 pounds 9 ounces, with other rows 

 declining gradually to 2 pounds 6 ounces at the fifth row, which was 

 about the average for the remainder of the field. That the open 

 rows and outstanding individual plants escaped injury to such an 

 extent seems to show that the insects required the shelter of the boll- 

 weevil cotton and were unable or unwilling to come out and work 

 in the open, even on plants only a few feet away. 



OPEN LANES BETWEEN COTTON ROWS. 



The facts already stated emphasize the need of cultural methods 

 that will keep the plants upright and the lanes well open between 

 the rows, avoiding as far as possible the spreading plants, heavy 

 foliage, and continuously shaded ground that mark the condition of 

 boll-weevil cotton. Cultural control of the form and branching of 

 the plants is the more possible because the large plants do not differ 



