THE MELON PLY. 27 
during the winter, but feed continuously throughout this period, it 
is evident that any spray that will kill them before they begin to lay 
eggs is valuable. A poisoned-bait spray^ containing 5 ounces of lead 
arsenate in paste form, 2-J pounds of brown sugar, and 5 gallons 
of water, is very effective in killing adults. This spray, used at the 
rate of 30 gallons to the acre, was applied by means of a knapsack 
sprayer. About 2 acres of Chinese melons and cucumbers in a field 
fairly well isolated, from the Hawaiian standpoint, Avhich means 
that no host fruits were growing within 500 yards, were sprayed on 
May 21, 26, and 28^ June 1, 4, 8, 14, and 23 during typical summer 
weather. Six hours after an application many adults were sluggish 
and flew with difficulty, but within 24 hours many dead adults could 
be found among the vines. Although the adults were lessened nu- 
merically by the spray, the young fruits were punctured as badly at 
the end of the experiment as at the beginning. 
Although negative results have followed the use of poisoned-bait 
sprays in Hawaii, failure has been due to the peculiar conditions sur- 
rounding the fields sprayed that permit an influx of female flies. 
Under commercial conditions, where cantaloupes, pumpkins, and 
watermelons are grown in large quantities in fairly dry climates, it is 
reasonable to believe that sufficiently good results will follow the 
use of poisoned sprays to make their application practicable as a 
method of control. 
DESTRUCTION OF INFESTED FRUITS. 
Larvse and eggs may be killed by submerging the infested por- 
tions of the plant in water, or by burjnng, boiling, or burning. Choice 
of method will depend largely upon the amount of fruit to be 
handled and upon local conditions. There is no surer way to kill all 
immature stages than to boil or burn the fruits. Burning is often 
expensive, and, when trash in compost holes is depended upon to 
furnish the fuel, is likely to be unsatisfactory, particularly where, as 
in Honolulu, the quantity of infested material is so great. Bringing 
infested fruits to the boiling point will kill all forms. The sub- 
merging of fruits in ordinary tap water for five days will either 
kill all larvae and eggs or stop further development. 
Burial in soil is a satisfactory method, provided the fruits are 
buried deep enough and cracks are prevented from developing in 
the earth above the fruits as the latter decay and settle. It must 
be remembered that just after transforming from the pupa the 
adults are so soft that they can force their way through very small 
openings. A crack in the soil extending down to the fruit, even 
though it be no wider than ordinary blotting paper, is still wide 
enough to allow the adults to reach the surface and thwart the pur- 
pose of fruit burial. Adults can not make their way through a foot 
