May 27, 1937. to show the results secured by spraying with lead arsenate to 
prevent May beetles from defoliating pecan trees. 
Five applications of the lead arsenate spray caused burning of the 
foliage on sprayed trees from 2 to 6 weeks after the last spray was applied. 
Foliage injury was severe on 6 trees and was of no practical importance on 
the remainder of the sprayed trees. 
The discontinuance of the work in northern Louisiana prevented fur- 
ther experiments with spraying for beetle control. It is believed, however, 
that three properly timed spray applications, starting when the beetles 
first appear, should give reasonable protection. This should be used only 
in areas in which experience has indicated that lead arsenate can be applied 
without serious burning of the foliage. The danger of foliage injury should 
of course be less with three applications than with five, as used in the 
experiments. 
The average quantity of spray liquid required in the experiments of 
1937, for the trees which varied from 8 to 20 feet in height, was approximate- 
ly 4 gallons. With lead arsenate at 12 cents per pound, and hydrated lime 
at 2/3 cent per pound, the cost for spray materials per application would 
average about 1| cents for trees of the sizes shown in figures 2 and 3. The 
spraying of larger, older trees would of course cost more, but trees of this 
type are less likely to need protection. 
