4-H CLUB INSECT MANUAL 63 
The information gained from surveys with reference to the cotton 
boll weevil would be important. The early spring survey to be made 
about the time cotton is chopped would indicate the number of wee- 
vils emerging from hibernation. When 40 or more weevils per acre 
are present on any given field, control measures are likely to be 
necessary on that field and arrangements for applying such measures 
should be made. 
The square-infestation survey should be made on each field when 
the cotton begins to fruit, to determine when 10 percent of the squares 
are infested. If cloudy, rainy weather, which is favorable to boll 
weevil development, prevails, dusting with calcium arsenate should 
be started. 
The occurrence of scale insects increases and decreases from year 
to year. Too often damaging infestations are not located until the 
trees or shrubs are in foliage. Control measures for scale insects 
are applied while trees are in the dormant period. If the public 
could be taught to be on the lookout for these pests and to consult 
entomologists, control measures could be started during the dormant 
period before damage to the trees occurs. 
Possibly one of the best examples of the effectiveness of surveys 
is that made for the hessian fly. Through a survey made each sum- 
mer by entomologists, the danger of hessian fly infestation in wheat 
sown in the fall is determined, and if necessary the farmers are 
warned to observe the safe seeding dates. Club “members in terri- 
tory where the hessian fly is prevalent could, by familiarizing them- 
selves with the survey, do much to assist entomologists, as well as 
to educate farmers, regarding the value of withholding planting until 
after the safe seeding date. 
U.S. GOVERNMENT PRINTING OFFICE: 1939 
For sale by the Superintendent of Documents, Washington, D. C. - - - - - Price 10 cents 
