18 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1933 
The eradication of the small, experimental plantings of cultivated and wild 
cotton at Chapman Field has been carried on in cooperation with the Bureau 
of Plant Industry. A few plants have been left in each of the plots so as to avoid 
any possibility of driving the pests to some other malvaceous plant. All the 
fruit was removed from the plants which were left, and throughout the year 
the blooms have been removed daily. These blooms were found to be infested 
during the summer of 1932, but from October 7 to March 3, 1933, the examinations 
were negative.. During the period March 3 to 24, 1933, 11 pink-bollworm larvae 
were taken from blooms in one of the plots, but all examinations between then 
and the end of the fiscal year have been negative. This would apparently 
indicate that the light infestation was due to overwintering larvae in the soil and 
not to reinfestation from outside sources. 
CLEAN-UP OF BIG BEND AEEA OF TEXAS UNDERTAKEN 
The Big Bend section of Texas is comprised of the counties of Brewster and 
Presidio, most of the cotton acreage being in Presidio. During the 1931 crop 
season the infestation was heavier than ever before, practically all bolls being 
infested before the end of the season, and* the loss to farmers was exceedingly 
heavy. Early investigations indicated that the infestation would be even heavier 
during the 1932 crop season. Such intense infestation makes the prevention of 
spread by quarantine methods all the more difficult, and plans were accordingly 
made to try to reduce this infestation to insure that the quarantine would give 
the necessary protection to the Cotton Belt proper. The plans were to make a 
thorough clean-up of the fields after picking had been completed, have the farmers 
delay the planting date for the following crop, and make use of trap plots of 
cotton. 
Complications, however, prevented these plans from being carried out in full 
detail. In the early part of September a flood came down the Conchos River of 
Mexico, which empties into the Rio Grande about 2 miles above Presidio. All 
the cotton acreage on the Mexican side of the river, and approximately 1,200 
acres in Presidio County, were flooded. About 3 weeks later floods came down 
the Rio Grande and the Conchos River at the same time and covered practically 
all the cotton acreage of the Big Bend. This made the field clean-up much 
more difficult than it otherwise would have been. Silt was deposited about 
the fields which prevented the use of machinery; it was necessary, therefore, to 
cut the stalks with machetes and have the clean-up done by hand. 
The work was begun early in November and completed the latter part of 
January. A total of 4,106 acres was cleaned at an average cost of $4 per acre. 
There was considerable drift material along the river containing cotton which 
had been washed from the fields, and after the field clean-up was completed, 
this drift material was burned. Following this a house-to-house canvass was 
made, and all places where cotton had been stored were cleaned as were also all 
trucks and other vehicles which had been used to transport cotton. All seed 
cotton in mattresses and pillows was replaced with linters. 
The peak of moth emergence in the Big Bend is completed by the latter part 
of May. Cotton planted after April 15 does not have blooms before the middle 
of June; therefore, all farmers were requested not to plant cotton before this 
date (April 15), so that the peak of moth emergence would be over before the 
cotton reached the point where the insect could be propagated. Every farmer 
willingly obeyed this request, as they were all familiar with the damage the 
pink bollworm could do. 
In order to attract moths emerging later in the season early plots of cotton 
were planted in advance of the main crop to act as traps. This plan had worked 
out very well in the Salt River Valley of Arizona, where stub cotton could be 
used as a trap. Such stub cotton was not available in the Big Bend; therefore, 
it was necessary to plant cotton in hotbeds and later transfer it to the fields. 
After an early set-back from cold weather, this cotton began growing very nicely 
and had blooms about a month in advance of the main crop. A total of 67 plots, 
containing about 200 plants each, were set out, which gave an average of 1 plot 
to each 37.7 acres of cultivated cotton. The blooms from this cotton were 
collected daily, and after being inspected they were burned. The first infested 
blooms were collected early in June. By the end of the fiscal year infested blooms 
were being found in 47 of the 67 plots. A few blooms were beginning to appear 
in the commercial cotton fields, and infested blooms had been found in some 14 
fields, but the pink-bollworm moths were clearly being attracted to the early 
cotton plots much more readily than to the cotton fields. 
