Multicolored Asian lady beetle
Fig. 1. Multicolored Asian lady beetles infesting an apple.
Photo: Eric Burkness
Fig. 2. Multicolored Asian lady beetles infesting an apple
The multicolored Asian lady beetle is a relatively new pest of fruit in Minnesota. Growers may find ripe or nearly-ripe apples with fairly large cavities in them, and a number of lady beetles inside, eating the apple’s flesh. This is the same lady beetle that sometimes invades houses or congregates on the sides of buildings. Information about this insect when it is associated with buildings can be found in the University of Minnesota Extension publication Multicolored Asian lady beetles.
The multicolored Asian lady beetle is a large lady beetle, up to 1/3” long. It may be yellowish-orange, bright orange, or darker reddish-orange. This lady beetle typically has nineteen spots, although this number is quite variable and individuals may have no spots and every combination of even numbers from two to eighteen. However, if you find lady beetles feeding in apples, you may be sure they are multicolored Asian lady beetles.
There are many lady beetles in Minnesota, all of which are predators, eating soft-bodied insects, especially aphids. In this way, they are considered beneficial. Populations of multicolored Asian lady beetles are common in wooded areas, agriculture fields, and home gardens. As their preferred prey become scarce, these lady beetles fly to another food source, often fall-ripening fruit such as grapes, apples, and fall raspberries. These insects only infest apples that already have wounds, typically holes made by birds or other insects.
The only management option for multicolored Asian lady beetles in apple plantings is sanitation. They only infest fruit that is already damaged, so picking up fallen apples and removing damaged apples still on the tree will help reduce the number of lady beetles in your apple planting. Insecticides are not a practical option.