Fruit Tree Insects
What is apple maggot?
The apple maggot (Rhagoletis pomonella), is a pest native to North America that has caused considerable damage to fruit crops and apple orchards. Heavily infested trees can have distorted fruit limiting their market to cider and animal feed.
Apple maggot is a type of fly that is a pest primarily on apples and crabapples, as well as other fruits. Efforts to control this fly are varied including insecticides, sticky traps, bags to protect fruit, and biological control with natural predators.
Diagnosis
• Adult flies are small with conspicuous dark markings on wings and a white spot on their back
• Damage to fruit consists of stippling and dimples caused by the adult fly laying eggs
• These dimples are called “stings” and as the larvae mature they can cause the pulp to breakdown and the fruit to rot
What To Do
Fruit trees in the landscape setting can be treated with pesticides to reduce the damage caused by this pest. Other preventative measures can be taken as well to further ensure viable yields. Any unharvested or fallen fruit should be removed or destroyed surrounding the tree. If you are looking to protect the current year’s fruit another option is to cover newly forming fruit with paper, or specific fruit bags. Sticky traps can be used to catch adults as well as give an indication on when to begin pesticide treatments. A mixture of cultural and chemical control methods should be used for the best control. Rotating between different pesticides is a good management practice to reduce resistance in apple maggot populations.
QUICK FACTS
- Even small numbers of apple maggot can cause major damage to apple yields
- Apple maggot has one generation per year and overwinters in the ground as a pupae
- Primary damage from this pest is caused by the adult fly creating a hole in the fruit to lay eggs making the fruit unmarketable or particularly unappealing for consumption
MANAGING APPLE MAGGOT
Efforts to control apple maggot can vary depending on the time of year and pest severity. These methods can include insecticides, sticky traps, and biological control with natural predators. For the best control, a combination of chemical and cultural practices should be used. The main focus of the treatments will be on protecting the fruit.
Managing the Insect
There are many different insecticide treatments your arborist may recommend based on the timing and severity of the current infestation. The goal of insecticide sprays is to protect the newly developing fruit from larval attack and adult egg laying.
Applications are typically made once adults are caught in traps. From there your arborist will treat every 14 – 21 days if adults are still being found. Adult activity lessens as the year goes on and treatments may stop around August.
Other Treatment Practices
- Sanitation
- Destroy any remaining fruit from unharvested trees and remove fallen fruit from the ground surrounding the trees.
- Sticky Traps
- Traps are sold as red spheres with tanglefoot and possible scents.
- Traps are hung 1 per 100 fruit
- Fruit Bagging
- Prevent eggs being laid on fruit by covering the newly formed fruit with paper bags or specific fruit bags.
- Secure bags over fruit with string or twist tie. Avoid constricting the stem.