52 NEW YORK STATE MUSEUM 



APPLE MAGGOT 

 Rhagoletis pomonella Walsh 



The apple maggot or " railroad worm " appears to be coming to 

 the front in New York State as a pest, particularly in portions of 

 the Hudson valley where it has become so abundant in certain 

 orchards as to render nearly worthless, early sweet and subacid 

 varieties and seriously affect the winter fruit. 



Habits. This pest is well known as a local form and among 

 entomologists it has a reputation for erratic behavior. The parent 

 flies may be found on the fruit from some time in late June or early 

 July through to September, moving slowly about and occasionally 

 depositing a minute, white egg just under the skin. The egg punc- 

 tures are visible with the naked eye though not readily distinguish- 

 able without the aid of a hand lens, and in some varieties are accom- 

 panied late in the season by distinct depressions, simulating, to a 

 certain extent, those produced by red bug injury. They may be 

 found largely on the sides of the apple, rarely near the ends. Hatch- 

 ing occurs in from two to six days and the colorless maggots begin 

 to make almost invisible trails, frequently beneath the skin and 

 showing through as darkened areas, suggesting a railway line, hence 

 the popular name. As the maggots increase in size the burrow is 

 larger, and in the case of a serious infestation the interior of the fruit 

 may be a brownish, decaying mass traversed by interlacing galleries. 

 The maggots may attain full development in two weeks though in 

 unripe fruit and especially during cool weather, feeding and growth 

 may be considerably prolonged and cover a period of several months. 

 The fully grown maggots leave the fruit through irregular holes and 

 enter the soil to the depth of an inch or two for the final transfor- 

 mations, which latter may occur the same season, be deferred to 

 the next or even delayed until the second summer. This delayed 

 transformation or biennial habit may be more general than has been 

 suspected hitherto. ' There is a generation in the early fruit, some 

 of which at least may produce flies the same season. The flies also 

 attack the later fall and winter apples, there apparently being 

 some correlation between the appearance of the adults and the 

 development of the fruit. 



Food habits. The food habits of this common pest are some- 

 what more variable than is usually supposed, the insect having 

 been reared from thorn apples or wild haws, huckleberries and 

 blueberries, and there are also records of the pest attacking pears, 

 though this latter appears to be exceptional. 



