Cherry fruit fly

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Cherry fruit fly
Rhagoletis cerasi01.jpg

Cherry fruit fly ( Rhagoletis cerasi )

Systematics
Family : Drill flies (Tephritidae)
Subfamily : Trypetinae
Tribe : Carpomyini
Sub tribus : Carpomyina
Genre : Rhagoletis
Type : Cherry fruit fly
Scientific name
Rhagoletis cerasi
( Linnaeus , 1758)

The cherry fruit fly ( Rhagoletis cerasi ) is a fly from the family of bored flies (Tephritidae). It is the most important pest in sweet cherry cultivation, as its maggot develops in cherries.

features

The flies become 3.5 to 5 millimeters long. They have a black body with yellow spots on the head and thorax . The scutellum is yellow. Their wings are transparent and very characteristically colored with four black-blue bands. They have green compound eyes .

The larvae reach a length of four to six millimeters and have a whitish colored body.

Cherry fruit fly on a cherry
Made of cherry fruit fly in an open cherry

Way of life

The larvae of the flies develop in the fruits of bird cherries ( Prunus avium ), sour cherries ( Prunus cerasus ), honeysuckle ( Lonicera ), snowberries ( Symphoricarpos ) and common bird cherries ( Prunus ).

The flight time of the cherry fruit flies is between the end of May and the beginning of July, depending on the temperature. When the sun is shining, the flies sit on the leaves and fruits of the larval food plants and suck up emerging sap. 10 to 15 days after hatching, the females begin to lay eggs in warm weather. 50 to 80 eggs are laid, each of which is laid individually below the epidermis of ripening fruits. After 5 to 12 days, the maggots hatch and feed on the pulp around the core. As a result, the fruit begins to rot and falls to the ground. The larvae are fully grown after about 30 days and leave the fruit in order to bury themselves in the soil at a depth of a few centimeters and to pupate. If the fruit does not fall off, the animals let themselves down on a spider thread. The insects overwinter. The pupae can also lay over two or three times before the imago hatches in the second or third year.

At the time of flight, cool temperatures and high rainfall reduce the populations of the flies. Accordingly, the cherry trees are particularly infested in dry years. The fruit fly also tends to attack late varieties , as early varieties ripen when the flies have not yet developed properly.

Combat

To combat the cherry fruit fly in amateur horticulture, so-called yellow traps are marketed. When the cherries begin to turn yellow, these are hung on the south and west side of the tree and remind the flies of the color of the cherries. The fly traps are coated with glue, which causes the flies to stick when they try to lay their eggs. Some traps are delivered with an attractant that encourages the flies to prefer the trap as a flight target. Two traps should be used per meter of tree height. A single fly can lay up to 200 eggs and infest more than a kilogram of cherries. Placing yellow traps is insufficient to protect all fruit from maggot infestation.

By completely harvesting the tree (including poor quality or spoiled cherries) and removing all fallen fruit as soon as possible, you can prevent maggots from migrating into the ground and infecting cherries in the following year.

To prevent severe infestation, cherry varieties can be planted whose fruits have not yet ripened enough or have already been harvested at the time the eggs are laid. Depending on the location's climate, the eggs are laid at different times, which means that it depends on the location which varieties are less susceptible. Chickens and ducks scratch the pupae out of the ground and eat them. Even the fallen fruit is often cut off from these animals. An insulating ground cover, e.g. B. with mulch material , delays the warming of the soil and thus the hatching of the flies. If the tree is in a meadow, it is beneficial not to mow it until the cherry harvest.

Organic farming

In organic farming, the cherries are protected by a close-meshed net (e.g. a cherry tree protective net ). Since it is not possible to completely net this in large trees, the tree is regularly pruned so that it remains small and the net can be extended over the entire tree. In the organic farming insects harmful fungi are used.

Conventional farming

In conventional fruit cultivation, there is a regulation that only cherries that may be infested with maggots to a maximum of 2% may be sold. Until a few years ago, this was achieved through the use of the insecticide Lebaycid . This poison was banned in Germany due to its negative impact on the environment. As an alternative, dimethoate has been approved for combating the cherry fruit fly, which is also very effective, but leads to an infestation rate that is very close to the approved limit value. Agricultural institutes and pesticide manufacturers then carried out large-scale studies on the effectiveness of other preparations for controlling the cherry fruit fly. It turned out that pyrethrum and neem preparations also have a certain effectiveness against the cherry fruit fly and, in combination with other insecticides, can reduce the infestation rate to almost zero. In addition, the active ingredient acetamiprid has been approved for pest control in conventional fruit growing across the EU since 2005 .

swell

Web links

Commons : Kirschfruchtfliege  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ Fungus against cherry fruit fly . In: oekolandbau.de . May 28, 2014 ( oekolandbau.de [accessed July 30, 2017]).