|
What is it?
Blueberry maggots are of the species rhagoletis mendax. Rhagoletis mendax is also sometimes called by the name blueberry fruitfly and is known as the most significant and dangerous insect pest to blueberry plants and harvests in the Midwest. Blueberry maggots are also particularly bothersome to blueberry crops on the East Coast. Although these insect pests only feed on blueberry plants for 20 days after they hatch, one large infestation can destroy a blueberry crop in a small period of time.
What does it look like?
Rhagoletis mendax is a small white maggot, hence the name blueberry maggot. These white maggots are only about 3/8 inch long at their largest size. Rhagoletis mendax feeds on the insides of the blueberries, eating the soft pulpy material of the fruit and often leaving behind a dried out or shirveled looking husk. You may first note the presence of the blueberry maggot, not by seeing the maggots themselves, but because your blueberry plants seem very sticky. Blueberries may leak excessive juice, and be soft and mushy rather than firm to the touch like healthy growing and developing blueberries. As the blueberry maggot is indiscriminate, the blueberries do not necessarily need to be ripened before damage can be noticed. Rhagoletis mendax attacks both the green, developing berries as well as the mature blueberry fruits.
How does it manifest?
Rhagoletis mendax in its adult female form begins to lay eggs during the latter part of the growing season for blueberries. The adult female flies lay their eggs anytime from late June to mid August. Primarily, the adult female flies lay the eggs just beneath the developing blueberry skins between the skin and the pulp of the fruits. Due to the placement of the eggs, when the eggs hatch they can immediately begin feeding on the blueberries insides, which they do for a period of approximately 20 days. After the 20 day feeding period has elapsed, the blueberry maggots then drop onto the ground and burrow into the soil. The blueberry maggots then pupate in the soil from anywhere from one to two years. Amazingly, these insects can pupate for extended periods of time in uncultivated soil. The one good thing about blueberry maggots is that they only produce one generation each year, so that controlling them is not as difficult as it would be if they were able to produce more than one generation per year.
What can you do about it?
Infested blueberries must be hand picked and destroyed as once the blueberries are infested they are no longer edible. The only way to truly control the population of rhagoletis mendax is to treat the plants at the start of the season, by spraying with a diazinon containing insecticide starting as early as July. Then, repeat the treatment at ten day intervals. You may need to continue with insecticide applications at tend day intervals for the entire growing season if populations of blueberry maggots are especially severe. If you replant your blueberries in the same region the following season, you may need to continue to treat the area for a period of two more growing seasons to control any blueberry maggots which may have pupated and emerged during that two year period.
| 
