State Size Features
Larva 5-7 mm, without legs, white. Possible confusion with fruit fly (Ceratitis capitata) or drosophila with spotted wings (Drosophylla suzukii)
Adult 3-5 mm, black body and yellowish brown head, with the yellow thorax in its final part (scutellum). The wings are transparent, smoked, and have black, V-shaped spots at the end of each wing.
Adults emerge from mid-May to July, easily visible in the sunniest areas of the tree. After reproduction, the female stings the cherry by introducing an egg under the epidermis. The larva feeds on the pulp, digging galleries and reaching the bone.
After completing its development emerges from the fruit and is dropped to the ground where it will pupate a few centimeters deep until next spring. A percentage of the population can continue in the pupal stage for several years (diapause).
Symptoms / Damage
The first symptoms will be observed in the fruits located in the sunniest area of the tree, the south face, which is the most frequented by adults and on which we will focus chemical treatments.
The affected fruits soften and end up rotting, being the reason of automatic destrium.
The stings of the adult at the time of introducing the egg cause a premature color change. Finally brown spots and an exit hole of the larva are observed.
Fruits with the presence of larvae fall to the ground easily.
Normally the female has only one egg per fruit unless there is a large population, and then several larvae per fruit.
This fact makes it possible to differentiate the symptoms of another fly that affects the cherry in some areas of Spain, Drosophylla suzukii, which usually lays several eggs per fruit, observing the corresponding bites and then larvae inside.
The damage, which can be total if an adequate containment plan is not carried out, is greater in late varieties and when the weather is warm and sunny. On the other hand, low temperatures and rains significantly reduce the activity of adults.
The cherry fly has a phased adult emergence period. Each female usually lays about 80 eggs, of the order of 10 per day, so that in a week the damage of a single female is important. The putting is done almost exclusively at veraison, that is, at the beginning of the change of color of the fruit, being the most critical moment. It does not sting the green fruit or when it is already mature.
The treatments should be initiated after observing the first flights of adults, although in practice they usually begin systematically when the fruit is young and begins to be receptive to bites. Applications are repeated weekly throughout the maturation period until collection.
The capture of adults through traps is an essential tool that allows an early diagnosis and provides information about the density of the pest in each moment.
They are placed before the start of adult flight and several types of trap can be used: sticky yellow sheets (chromatic traps), or flyers primed with the pheromone specified for Rhagoletis cerasi (2 traps / Ha for monitoring), which can be combined systems.
It is recommended to till the ground in summer to destroy the pupae by exposing them to the surface.
It is convenient to remove any fruit from the soil, to avoid the spread of the pest.
Collect as soon as possible and use early varieties in areas where the pest is too problematic. Varieties that change color when pest levels are maximum, are fatal.