62 BULLETIN 1374, U. S. DEPARTMENT OF AGRICULTURE 
The records show increases in yield for all the treated plats, the 
increase being greatest in the plats that received early treatment. 
Records of blooming and bolls produced should be considered in 
connection with the yields. Bloom counts were made weekly in each 
plat, and bolls were counted just before the first pick and shortly 
before the second pick. The individual plat averages for both 
blooms and bolls of the first crop are comparable among themselves 
about as the yields of the first pick in the same plats. This holds 
true, more or less, also with the second crop of blooms and bolls and 
the yields of the second pick. According to these records the increase 
in yield of the treated plats can not be ascribed entirely to reduction 
of the pink bollworm damage, but the poisoning evidently reduced 
the infestation. 
Each boll count represents an average from 50 plants at each of 3 
Eoints per plat. The count of the first crop of Bolls included only 
oils that were open just before the first picking. All of the first- 
crop bolls were open at this time, but hardly any of those of the 
second crop. Boll counts for the second crop were made several 
weeks before the second picking and included both open and nearly 
grown green bolls. No doubt the shedding of some of these green 
bolls and the failure of others to open by the time of the second 
picking, the smaller size of the bolls of the second crop, and the non- 
pickable cotton practically all of which was of the second growth, all 
contributed toward the much greater difference that is found between 
the yields of the first and the second picking than that found between 
the records of total bolls of the first and of the second crop. 
Of three other series of poison tests conducted in 1922, two showed 
increases in yield in treated plats. In the third there was a very 
slight decrease. 
COMPAEATIVE EFFECTIVENESS OF DIFFERENT POISONS 
Reduction in infestation was brought about by all three poisons 
used in 1922. Sufficient experiments have not been made to deter- 
mine whether one is more effective than the others. Because the 
6-plat series treated with arsenite of zinc was left incomplete, a 
comparison of the effectiveness of the three kinds of poison can be 
based only on the results obtained in the two latest poisoned plats in 
each of three 6-plat series on which different poisons were used. 
This comparison of the poisons is shown in Table 50. 
Table 50. — Comparison of average infestation in plats treated with different kinds 
of poison 
Plat No. 
Treatment 
Average number of worms per 
boll per examination 
Calcium Arsenite Lead 
arsenate of zinc arsenate 
land 6 Check » 5. 13 15.13' i 5. 13 
4 Aug. 9 to Sept. 7 4.29 4.30 4.19 
5 Aug. 22 to Sept. 26 4.07 4.17 4.15 
'Average of checks, all series. 
