6 BULLETIN 1320, U. S. DEPARTMENT OF AGRICULTURE 
TABLE 3.—Relation of temperature to the development of cotton plants as grown in 
successive plantings at San Antonio on four different dates 
[The temperatures shown (° F.) cover the petied tou Se date of seed germination to the first appearance 
of squares 
oo 
Average tempera- 
Date of | Number | Number NES ture 
i Date planted, 1923 germi- |of days to} of nodes Ey a eee i 
Nation | squarin formed KR 
Piprape per node| Mini- | Maxi- 
mum mum 
| | 
Dp 193k eee ANI ea fos 37 6.5 5.7 64.4 88.5 
TARDY 20 ge Meee se ace ee ge | May 4} 35 | Teil 4.9 66. 5 90.8 
Tal EA Ry ee ae I See Ay Sep ati ae Re es NY Lear? 2 27 6.2 4.4 68.6 $2.3 
IVES ya De NGI ges Rots NE PA on ONE | May 20 26 5.9 4,4 70. 7 94. 0 
Tt will be noted that the interval between the development of suc- 
cessive nodes decreases when higher temperatures occur during the 
period from Sonu eed de to the appearance of squares. The average 
rate of nodal development during the seedling stage of the April 19 
planting was 5.7 days. During this period the average minimum 
temperature was 64.4° and the average maximum 88.5° F. The May 
12 planting averaged 4.4 days per node during the seedling stage of 
the plants, the average minimum and maximum temperatures having 
been 70.7° and 94° F., respectively. 
DAMAGE BY OVERWINTERED WEEVILS 
The extent of weevil infestation in the successive plantings of cot- 
ton was determined on June 5 by recording the numbers and per- | 
centages of squares that had been attacked by weevils. On June 5 
squares were present only on the April 19 planting. Even on this 
there were only a few large squares, and it was necessary to examine 
about 200 plants in order to find 100 squares that were regarded as 
over 10 days old. Records of growth of squares have indicated that a 
period of about 10 days elapses between the time when a square 1s 
first visible and the time when it has reached sufficient size to harbor 
a weevil larva.” 
In block 1 of the April 19 planting, which was located on the south 
side of the field, 45 per cent of the squares were punctured by weevils. 
Block 2, in the center of the field, had 20 per cent of the squares 
punctured, and block 3, on the north side of the field, had 15 per cent 
of punctured squares. 
The heavier infestation in block 1 may have been due to the fact 
that the field adjomed a Johnson grass pasture on the south. A 
large part of the weevil emergence probably occurred from this 
asture, and a large number of the weevils would doubtless remain in 
the first cotton where squares were found. 
STRIPPING OF FLORAL BUDS OR “SQUARES” 
Squares were removed on June 12 from the first and second plant- 
ings, and the entire field was poisoned with calcium arsenate. At 
that time the squares on the third and fourth plantings were below 
the size for stripping, so that it was necessary only to apply poison. 
pete Wes gta 2 ae el ee 
2 Martin, R. D., W. W. Ballard, and D. M. Simpson. Growth of fruiting parts in cotton plants. In 
Jour. Agr. Research, v. 25, p. 202. 1923. 
