12 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1951 
Observations show thai when cotton stalks are (, ut in extremely 
hot, dry weather a high percentage of the pink bollworm Larvae in 
bolls exposed on the soil surface are killed by the heat 
Hibernation experiments conducted over a B-year period at I'-'_ r 
Spring in tlif South Plain- area of Texas showed thai the pink holl- 
worm survives the * inter there. 
Fink Bollworm Quarantine and Control Continued 
Late ttalh destruction causes widespread infestations 
Destruction of cotton stalks for cultural control of the pink boll- 
worm did not meet the deadlines sel in much of south Texas in t he 
fall of L949, largely because of weather favorable for a tup crop but 
unfavorable for -talk dest ruction. A- a result, cotton in a number of 
fields fruited Late, some in Nueces County not until November. During 
the spring <>f 1950 more than 7:» percent of the fields examined in 
Nueces County had infested blooms. Tin 1 early infestations allowed 
heavy build-up of pink bollworms in many fields, result ing in the heav- 
iest infestation on record in tin- county. Very early in the crop 
season infestations from the fields spread by Sight or wind carriage 
of the moth to other parts of the infested area in south Tex a-. Further 
outward spread continued by natural flight into known infested areas 
and into previously uninfected counties. 
The heavy increases in infestation and the new outbreaks aroused 
cotton growers in south Texas to the need I'm- stalk destruction by 
the State-imposed deadlines. Stalk- in the Lower Rio Grande Valley 
were destroyed by the August 31 deadline. Fortunately, tin 1 more 
heavily infested fields in Nueces County were cleared of -talk- fully 
3 weeks ahead of the September 25 deadline. It was more difficult 
to obtain compliance with the September 25 deadline in several other 
Counties having dry-land areas in which a late crop of cotton had 
been planted. In counties with an October L5 deadline compliance 
an .i ^ more Dearly complete than in any other year since the require- 
ments went into effect . 
Record infestations found in 1950 cotton crop 
Inspections in the regulated part- of Arizona, New Mexico, Okla- 
homa, and Texas showed only 23 counties free from pink bollworm; 
64 were uninfested in L949. In addition to the infestation in Nueces 
( on my. Tex., there were increases in the infestat ions along the north- 
< in and eastern boundaries of the south Texas regulated area. Infes- 
tation was also heavier in central-west Texas and the South Plains 
section of the State. The Pecos Valley had a heavy build-up of pink 
bollworms and Presidio County suffered severe damage from them. 
The infestation in the El Paso Valley, however, was lighter. 
[nfestations were again found in Oklahoma. In New Mexico light 
tations recurred in most of the cotton growing counties. Arizona 
free of the pink bollworm for the second consecutive year. ln- 
itions were found \'<>v the first time in 35 counties in Texas, 8 
counties in Oklahoma, and 1 parishes in Louisiana. Eight of the 
newly infe ted Texas counties are primarily devoted t<» ranching and 
grow little cotton. The other 27 Texas counties extend from the Gulf 
i f Mexico to the Oklahoma boundary, forming an approximately 
