CODLING MOTH—PORTER 351 
and elsewhere. Nicotine sulfate with oil is likewise used in some locali- 
ties. Phenothiazine, when very finely ground, has given outstanding 
control in the Northwest, but has not come into commercial use be- 
cause of the unfavorable effects on the fruit and on orchard workmen, 
and because of cost. The most recently discovered material is DDT 
(2,2-bis (parachloropheny]) -1,1,1-trichloroethane) which may outstrip 
all the others, although a final decision on its ultimate usefulness can 
be made only after more extensive tests have indicated its effects on 
the consumer, on orchard workers, on fruit trees, and on the beneficial 
insects that aid greatly in keeping orchard pests within bounds or 
that provide for the pollination of the fruit. 
DEVELOPMENT OF SPRAY MACHINERY 
Along with the evolution of materials and programs for codling 
moth control has been the development of spray machinery for the 
application of the insecticides. The original hand-operated, back- 
breaking barrel pumps soon gave way to crude power-operated outfits 
(pls. 4,5). Power spraying equipment has been steadily improved, 
coincident with the development of the automobile and airplane. The 
grower now has his choice of stationary sprayers, which pump the 
spray mixtures from a central plant through overhead or underground 
pipes to outlets placed at suitable intervals through the orchard, 
standard portable rigs (pl. 6, fig. 1), or the recently developed air- 
blast type of sprayer (pl. 6, fig. 2), which delivers the spray by means 
of the blast from a propeller similar to those used in airplanes. 
Present-day standard spray outfits give pressures up to 700 or 800 
pounds per square inch and will deliver 20 to 50 gallons per minute or 
more. A number of men can spray at the same time from the larger- 
capacity stationary sprayers. 
CONTINUED DIFFICULTIES IN CONTROL 
With the development of improved spray materials and mixtures, 
high-power, large-capacity spray machinery, and carefully worked-out 
Spray programs, which all together result in spray deposits on fruit 
and foliage that would have been unbelievable 50 years ago, it would 
be natural to expect a corresponding improvement in codling moth 
control. Actually, however, nothing of the kind has occurred. Al]- 
though in most orchards the growers are obtaining a reasonable degree 
of control, there is no indication that the worms are any less abundant 
or destructive than they were 50 years ago. In fact, in some areas 
the growers are having more difficulty than ever before in controlling 
the worms. In such areas, in which conditions favor the insect, 20 
or 30 percent of the apples are often wormy at harvest time, in spite 
of the making of 8.to 10 spray applications during the season, and the 
