- 2 - 

 -BLUEBERRI mOGOT- 



The blueberry maggot has been noticed in abundance the past few seasons in the 

 fruit of cultivated blueberries in a few fields in the Cape Cod area. Maggot has 

 been a problem to the blueberry industry in other areas for a good many years and 

 there is no reason to believe that it will not be an increasing problem in South-- 

 eastern Massachusetts as the industry expands. 



The blueberry maggot is a native insect that infests both wild and culti- 

 vated blueberries and some related fruits from New Jersey northward wherever its host 

 plants are found. To avoid maggot infested fruit at harvest it has been found neces- 

 sary to dust or spray for this insect in the cultivated blueberry fields of New Jersey 

 and the areas of wild lowbush blueberries that are harvested in New England and else- 

 where. 



The blueberry maggot is apparently a strain of the apple maggot, the only 

 difference being that the blueberry infesting strain is smaller in size. This size 

 difference is especially marked in maggots that infest the smaller fruited wild 

 varieties, while maggots developing in some of the larger cultivated bluebercy varie- 

 ties approximate apple maggots in size. 



Like the apple maggot the blueberry maggot has one generation a year. 

 The winter is passed in the pupal stage in a quarter inch brown puparia buried in 

 the soil within a few inches of the surface. The flies emerge for about a month in 

 the summer beginning about the time the first blueberries start to turn blue« They 

 are blac^ in color with white bands on the abdomen and are smaller than a house fly 

 though similar in shape. The wings are marked with characteristic oblique black 

 bands. The flies do not lay eggs until about 10 days after they have emerged. Eggs 

 are layed singly under the skin of the blueberry c The eggs hatch in about a week and 

 the maggots leave the berries and enter the soil and form puparia in v/hich they re- 

 main until the next or some following spring vrhen they emerge as flies. Some of the 

 maggots remain in the puparia for two or more years before emerging, and as these 

 emerge later than those that emerge after one winter in the soil they complicate 

 control. 



Though the flies apparently prefer ripe fruit in which to lay eggs, if they 

 appear before the fruit is ripe or if they are abundant, they will lay eggs in_ green 

 fruit as well as ripe berries during the harvest season. Consequently the timing of 

 the first dust application is ideally based on fly emergence, but lacking this know- 

 ledge the first dust should be applied just as the first few berries are turning from 

 red to blue. Because there is about a 10-day interval between emergence of the fly 

 ani the time it can lay eggs, subsequent dustings are applied at 10-day intervals 

 after the f irst dust application^ The number of dusts applied will depend on the 

 length of the harvest season, with three dusts usvially a minimum number and four or 

 five being necessary in a late season and with a high prcentage of late varieties 

 in the field. 



Frequent picking of ripe fruit during the harvest season and prompt dis- 

 posal of the picked fruit helps in controlling maggot and reducing loss from it. In 

 no case should soft over-ripe fruit be shipped to market, though picking of such fruit 

 and removal from the field will help reduce the fly population the following season. 

 Vlhere practical, bushes should be picked clean as berries left on the bushes at the 

 end of the harvest season often become very heavily infested with maggots and are a 

 source of a large fly population in the next and following seasons. 



