55 ANM AL UKi'oirrs OF I >i:i'AK i .Mi;.\ r of AciiicFi/rrin:. vxn 
entomoluf^ist of ('.('ori^ia. :iim1 in lOchols (Nniiity. (la., in orxipcrat ion with llie 
Oei>rj;ia Coastal IMaiii ExiKTimcnt Station. In Arizona, in cooiHTation with 
the Arizona A^ricult nral KxprrinK'nt Station, .stndio.s were begnn at Mesa and 
Ynnia on the control of hcniipterons insects. For the work at Ynnia. liead- 
qnarters were established at the liureau of Plant Indnstrv field station at Bard, 
Calif. 
BOLL wkp:vil 
The year 1930 was notable becau.se of the comparatively small (hunaj;e caused 
by the boll weevil, the lo.sses by this insect lieing less than during any year 
since 1925. This unusual condition was caused by the low boll weevil injpula- 
tion entering? hibernation in the fall of 1935, by the low temperatures that 
caused high mortality among the hibernating weevils during the winter, and by 
the high temperatures and drought conditions during the 19."»«j gn»wing season 
in the States east of Texas. The weevil cau.^ed its greatest damage in Texas, 
lu eastern and southern Texas there was a higher survival of weevils in the 
spring of 1!>3(>: weather conditions were favoral)le for their development 
throughout the .season, and for the first time in many years the weevils caused 
a greater reduction in yield per acre in Texas than in any other Stale. The 
low winter temperatures caused the lowest survival in 193G ever recorded in 
the hibernation cages at Florence. S. C, and no survival in the cages at 
Eufaula, Okla. The survival of weevils was much lower than normal at 
Tallulah, La., but at College Station, Tex., it was several times higher in 1936 
than usual. The generally low survival over most of the Cotton Belt was 
followed by a very dry spring, with extremely high temperatures in May and 
June, which further reduced the number of weevils, except in eastern Texas. 
The drought was more prolonged in Oklahoma, where only 2.11 inches of rain 
fell in the !)9 days from June 8 to September 14. 193G, and the weevil infesta- 
tion was practically wiped out. At Tallulah, La., approximately 90 percent 
of the grubs in the infested squares were killed by climatic conditions during 
the latter part of June. As a result of the low survival and climatic control, 
the infestation did not build up until late in the se.i.son. and in many .sections 
no control m<\*isures were neces.sary. This low weevil population over most 
of the Cotton Belt was followed by an early and widespread infestation of 
leaf worms, which defoliated the cotton early and further reduced the weevil 
population that entered hibernation in the fall of 19.SG. 
The winter of 193(>-.'J7 was mild, and in the boll weevil hibernation exi)eri- 
ments at Florence. S. C, the survival was much hiirher than during ajiy spring 
since M-'Mi; at Tallulah. La., it was higher than in any spring since 1982. and 
at College Station, Tex., the survival of weevils was highest of any year since 
the experiments were started G years ago. Although in most areas the weevil 
mortality was low during the winter of 1936-37, the number of weevils present 
in the cotton fields in the spring of 19.37 depended chiefiy upon their abun- 
dance during the fall of 1930. At Florence the weevils were more abundant 
early in 1937 than during any year since 1932. In Florida, .southern Georgia, 
and Mississii)pi the weevil i)opulation was low. At Tallulah it was lower tlian 
during any recent year except r.»:;o. Cage experiments and field ob.servations 
indicated that many weevils emerg(»d later from hibernation than usual. 
During the early season of 1937 conditions were not particularly favorable for 
the weevils, and at midsununer the prospects were that 1!>37 would be another 
light boll weevil year except in the South Atlantic and eastern Texas areas. 
Mixtures of calcium arsenate and sulphur used for boll weevil control have 
in some experiments given greater gains in the yield of .-^eed cotton \m^t acre 
than undiluted calcium arsenate. These increased yields i»robably residt from 
additional control of the cotton flea hopper and other hemiptiTous ins«H-ts by 
the sulphur. These exi)eriments indicate iirogress in developing an tH'onomical 
insecticide that will give i)raclical control against the boll weevil, flea hopi>er, 
and other insects at the s.-inie time. 
Mixtures af calcium arsenate and lime Ih-ne in many instances given more 
l)rofitable iiK'reas(»s in yields than un(liluf(><l calcium arsenate. Tlu'se mixtures 
liave the advantage of recbicing the dangers of .soil injury and of heavy aphid 
infestation, and at the same time reducing the cost of weevil control. Although 
the tests in which tlu^ lime-calcium ai'senate mixtures have given better results 
tlian undilule<l calcium arsenate h.ive been in thc^ iir(»s(Mice of comparatively 
light boll weevil infestations, this has been th(^ n<u-mal condition in the boll 
weevil area during recent years. 
Tn cage test.s at Tallulah. La., with 20 dilTcrent brands of calcium arsenate 
ranging from 11.2 to 0.2 jxTcent in tcr soluble arsenic pentoxiih'. as deter- 
mined by the New Y(Mk method the boll weevil mortality ranged from 3J> to 
