Inventaire de la faune des acariens sur Amaranthus cruentus L. (Amaranthaceae); Solanum macrocarpon L. et Solanum aethiopicum L. (Solanaceae) dans le SudBenin

A survey of the mite fauna associated with Amaranthus cruentus L. (amaranth), Solanum macrocarpon L. (Gboma) and S. aethiopicum L. (African eggplant), three major indigenous vegetables produced in Benin, was carried out from August to October 2004 both at IITA-Benin station and on a vegetable farm at Togba in Abomey-Calavi area. Thirty-three mite species belonging to 12 families were found on the three vegetables. These species included phytophagous mites, predatory mites of the family Phytoseiidae, and another group whose feeding habits were not clear. The following phytophagous mites were found: Tetranychus urticae Koch and T. ludeni Zacher, in the family Tetranychidae; Polyphagotarsonemus latus (Banks) and another unidentified mite species, in the family Tarsonemidae. The two Tetranychus species were present on all three vegetables whereas tarsonemids were found only on the two solanaceous plants. Polyphagotarsonemus latus was the most dominant pest during the course of the experiments. It is the major mite pest on solanaceous plants, especially on Gboma in vegetable farms, where broad-spectrum pesticides harmful to natural enemies are used. The phytoseiids group was the most diversified with 16 species out of the 33 identified and more predominant in IITA plots where no pesticides were applied, compared to Togba plots where pesticides were regularly applied on nearby plots. They seem to better control P. latus on Gboma than on African eggplant. Other mites identified on the three vegetables belong to the following families: Acaridae, Tydeidae, Erythraeidae, Cunaxidae, Anystidae, Ascidae, Bdellidae, Uropodidae and Oribatidae.Un inventaire de la faune des acariens associes a Amaral1.thus cruentus L. (amarante), Solanum macrocarpon L. (Gboma), et SoLanum aethiopicwn L. (aubergin fricaine), h•ois principaux legumes indigenes cultives au Benin, a ete entrepris d'aout a octobre 2004 sur la Station de IITA Benin et sur Ie perimetre maraicher de Togba, deux sites situes aux environs d' Abomey-Calavi. Sur l'ensemble des deux sites, et sur les trois legumes, 33 especes d'acariens appartenant a 12 familles ont ete recensees. On y distingue des ravageurs, des predateurs de la famille Phytoseiidae, et un groupe compose d'acariens dont Ie mode d'alimentation reste a elucider. Les acariens ravageurs comprennent Tetranychus urticae Koch et T ludeni Zacher (Tetranychidae) et Polyphagotarsonemus latus (Banks) (Tarsonemidae) et un autre tarsoneme non identifie. Les deux especes de Tetral1ychus etaient presentes sur tous les legumes tandis que les tarsonemes etaient rencontres uniquement sur les solanacees. Polyphagotarsonemus latus etait l'acarien ravageur Ie plus dominant au cours de l'etude; et il infligeait plus de degats aux solanacees, specialement sur les parcelles de Cboma traitees avec des pesticides a large spectre en champs de fermiers. Les phytoseiides etaient les plus diversifies en especes (16), et plus abondants a IITA -lm site sans pesticide -qu'a Togba oll des pesticides etaient regulierement appliques dans Ie voisinage des parcelles experimentales. Ces acariens semblent contrOler P. latus mieux sur Cboma que sur l'aubergine africaine. Les autres acariens recenses appartiennent aux families des Acaridae, Tydeidae, Erythraeidae, Cunaxidae, Anystidae, Ascidae, Bdellidae, Uropodidae et Oribatidae