The More Important Apple Insects. 13 
APPLE MAGGOT OR “ RAILROAD WORM.”’ 
The apple maggot, a native insect, is commonly found in the New England 
States and Canada and also occurs in Michigan and other Northern States. 
When abundant, it presents a very serious problem and is likely to cause con 
siderable injury, particularly to the varieties most susceptible to attack. The 
work of this insect in its earlier larval stages is often very deceptive, and apples 
that appear sound externally are frequently infested with one or more maggots. 
As soon as the infested apples beconie mellow, however, the maggots develop 
rapidly and can be readily detected by the brownish tunnels which are often 
visible through the skin, especially with varieties having light or yellow‘sh 
colored skins (fig. 16). The larve or maggots make winding burrows or tracks 
throughout the flesh of the fruit and often reduce it to a brown pomace-like 
consistency, rendering it absolutely worthless for market purposes (Gi a) 
The original food plant of this insect was the haw, but at present the culti- 
vated apple is its principal economic host. Although there is a wide range of 
susceptibility among the several varieties of apples, usually the summer and fall 
sweet to subacid varieties are preferred, but in their absence the more acid, as 
well as the winter apples, are attacked as soon as they reach the proper state of 
maturity. In addition to the apple, this insect has been reported on pear, plum, 
eherry, huckleberry, blueberry, cranberry, mountain cranberry, and snowberry. 
The apple maggot passes the winter in the pupa stage beneath the surface of 
the so‘l, the true pupa being developed within the puparium a few days after 
the latter is formed. The puparium (fig. 18) is at first light brown, later be- 
comes darker, and is about three-sixteenths to one-fourth of an inch in length. 
The adults or flies first begin to issue during midsummer, usually in July, and 
depos‘t their eggs in the early varieties of apples, just beneath the skin of the 
fruit. The adult fly (fig. 19) is slightly smaller than the common house fly but 
is naturally somewhat sluggish unless disturbed, when it can dart quickly out 
of reach. The adult is shiny black in general color, the abdomen having four 
transverse white bands in the case of the female and three in the male, and 
the wings are marked with four irregular dark bands. The flies do not usually 
oviposit until a few weeks after emergence. The eggs are more or less yellow- 
ish white and average about one-thirtieth of an inch in length. They hatch 
in a few days and the resulting larve immediately begin to feed on the flesh 
of the fruit. After falling from the tree, the infested apples quickly mellow and 
shortly thereafter the full-grown larve leave the fruit and enter the ground. 
The larva (fig. 17) is whitish to yellowish white and when full grown Measures 
about three-eighths of an inch in length. 
Tn southern New England there is a small partial second eeneration, but the 
majority of the first brood do not transform to the adult stage until the follow- 
ing summer, and a small percentage remain in the ground until the second sum- 
mer, thus making for the latter a two-year life cycle. The flies of the first brood 
emerge during midsummer, while those of the second brood issue during the 
fall and deposit their eggs in the different varieties of fruit when it reaches the 
proper stage of maturity. 
The most practical method of reducing injury, though not as effective and 
dependable as desirable, is to spray the trees, beginning in early July, with 
arsenate of lead powder, using 1 pound, or 2 pounds of the paste, to each 50 
gallons of water. From two to three applications made at intervals of about 
two to three weeks will be required. The flies are killed by lapping the poison 
from the foliage and fruit. The prompt picking up and destruction of the 
3 Rhagoletis pomonetla Walsh. 
