Solanaceae fruit fly

Neoceratitis cyanescens (Bezzi)

General

• Very damaging insect on fruits belonging to the Tephritidae family, the Dacinae subfamily and the Ceratidini tribe.
• Described in Madagascar from where it is probably indigenous then introduced in certain islands of the Mascarenes and the Comoros.
• Rather specialized in plant species of the Solanaceae family, cultivated (tomato, eggplant, pepper, pepper, shrub tomato - Cyphomandra betacea -, Solanum aethiopicum ) or wild to subspontaneous (bringellier - Solanum auriculatum -, anguive - Solanum anguivi -, nightshade - Solanum nigrum -).
• Observed in the open field as well as under shelters.

• Sensitive botanical family (s)

• Affected production areas :

• Organs attacked

Symptoms, damage

• Symptoms :
  • Presence of more or less punctiform and discolored lesions corresponding to the bites of adults on the affected fruits; they are generally clearly visible (figures 1 to 3).
  • Rot progressively spreading to all the fruit as the maggots are active (figures 4 and 5). Note that this rot is caused by various pathogenic or opportunistic microorganisms that invade and break down the tissues.
  • On young tomato fruits, the first attacks appear very early, about ten days after flowering, when their diameter reaches 2 cm. The attack rate then increases rapidly and reaches its maximum about 3 weeks after flowering. Subsequently, older fruits may still be punctured, albeit more weakly.

• Signs : Presence of flies and larvae on and in the affected organs, and in the culture (figures 7 to 9).

• Possible confusion :

 Biology

• Biological cycle : composed of 5 stages (egg, 3 larval stages, pupa and adult) spanning 26 to 35 days depending on climatic conditions. Egg-laying by females beginning 4 to 6 days after mating using their pointed viscap; their eggs being deposited under the epidermis of the host fruit, a few millimeters deep.
  • Eggs (figure 6) hatching after 3 to 4 days of incubation and generating larvae which then burrow into the pulp of the fruit.
  • Larval cycle comprising three stages and lasting from 7 to 11 days (figures 7 and 8).
  • The maggots  at the end of their evolution leave the fruit with a sudden expansion to sink to a shallow depth in the ground, where the pupation takes place. The pupal stage lasts from 2 to 15 days.
  • Adults (figures 9 and 10) easily recognizable thanks to the characteristic brown bands present on their wings, and by their scutellum (posterior part of the thorax) entirely black in its apical half. Mating begins very soon after the emergence of adults.

Protection

• Weed the crop and its surroundings.
• Install  canvases  insect-proof at shelter openings.
• collect and destroy stung fruits or bury them in order to limit the multiplication of populations. The use of an augmentorium with a net is recommended to confine the flies (sufficiently small meshes) while letting out the parasitoid insects of the fly (sufficiently large meshes).
• Eliminate the various reservoir host plants that may be found near the production plots.
• Reasoning  chemical protection (e-phy site). Reason the fight by carrying out a visual control from the beginning of the period of fruit sensitivity, in order to start the treatments when the first attacks appear. Alternate the active ingredients to avoid the appearance of resistance.
• Certain natural auxiliaries (figures 11 and 12) can contribute to limiting the populations of N. cyanescens on reservoir plants or in untreated plots. A native larval parasitoid species, Psyttalia insignipennis (Granger) (= Austroopius ) was thus observed in Mayotte, with a reduced rate of parasitism (8%).
• There is currently no known attractant pheromone to trap male N. cyanescens.