Evaluation De Lâ€™activitÃ© Acaricide De Quelques Biopesticides Sur Lâ€™acarien TarsonÃ¨me, Polyphagotarsonemus Latus Banks (Acari : Tarsonemidae) Infestant Lâ€™aubergine Gboma (Solanum Macrocarpon L.) Au Sud-BÃ©nin
Authors: Etienne Adango , Alexis Onzo , Wilson Daoudou C. O. G. 
Published: June 2020

Lâ€™acarien tarsonÃ¨me, Polyphagotarsonemus latus Banks, est un important ravageur de lâ€™aubergine Gboma (Solanum macrocarpon L.), un lÃ©gume-feuille de grande consommation au BÃ©nin. La gestion de ce ravageur repose fondamentalement sur la lutte chimique avec toutes ses consÃ©quences sur la santÃ© et sur lâ€™environnement ; dâ€™oÃ¹ la nÃ©cessitÃ© de rechercher des solutions alternatives. Ainsi, la performance de trois biopesticides notamment huile de neem (Azadirachta indica A. Juss), extraits aqueux de hyptis (Hyptis suaveolens (L.) Poit, et du faux basilic (Ocimum gratissimum L), a Ã©tÃ© testÃ©e sur les Å“ufs et adultes de P. latus au laboratoire de paires avec celle de Acarius et Sunpyrifos, deux acaricides chimiques communÃ©ment utilisÃ©s au BÃ©nin. Aussi, leurs effets sur les densitÃ©s de population du ravageur et la productivitÃ© du Gboma ont-ils Ã©tÃ© Ã©valuÃ©s en plein champ. Au laboratoire, les taux moyens dâ€™Ã©closion des Å“ufs ont variÃ© significativement entre traitements, allant 36 Â± 5% Ã 80 Â± 5% (P < 0,0001). Le plus fort taux dâ€™Ã©closion a Ã©tÃ© enregistrÃ© sur le tÃ©moin et hyptis tandis que le plus fort dâ€™Ã©closion a Ã©tÃ© enregistrÃ© avec Acarius suivi du Sunpyrifos et de lâ€™huile de neem. Les taux de mortalitÃ© des adultes de P. latus ont Ã©galement variÃ© significativement entre les diffÃ©rents traitements allant de 43 Â± 2% Ã 100% (P < 0,0001). Les plus faibles mortalitÃ©s ont Ã©tÃ© enregistrÃ©es sur le tÃ©moin suivi de hyptis tandis que les plus forts taux ont Ã©tÃ© enregistrÃ©s, avec les doubles-doses de Acarius, Sunpyrifos et de lâ€™huile de neem. Au champ, les densitÃ©s moyennes par feuille des stades mobiles de P. latus ont variÃ© significativement entre traitements, allant de 5,37 Â± 0,59 et 2,71 Â± 0,37 individus (P < 0,0001) ; les densitÃ©s les plus fortes ayant Ã©tÃ© enregistrÃ©es sur le tÃ©moin tandis quâ€™aucune diffÃ©rence statistique nâ€™a Ã©tÃ© observÃ©e entre les cinq autres traitements. Les plus fortes productivitÃ©s de Gboma (kg/4 m2 ) ont Ã©tÃ© enregistrÃ©es avec lâ€™huile de neem (13,65 Â± 2,13), Sunpyrifos (11,10 Â± 1,66) et Acarius (10,76 Â± 1,32). Il sâ€™en dÃ©duit quâ€™en attendant des Ã©tudes complÃ©mentaires, lâ€™huile de neem peut Ãªtre recommandÃ©e comme alternative aux acaricides chimiques contre P. latus sur les parcelles de Gboma au Sud-BÃ©nin.
The broad mite, Polyphagotarsonemus latus Banks is a key pest of the nightshade, commonly called Gboma eggplant (Solanum macrocarpon L.), a staple leafy vegetable in Benin. Management of this pest relies on chemical control despite its harmful environmental and sanitary impacts. It urgestherefore to search for alternative methods. In that respect, performances of some biopesticides including neem oil (Azadirachta indica A. Juss), aqueous extracts of Hyptis suaveolens (L.) Poit and of Ocimum gratissimum L. (clove basil), were tested on egg and adult stages of P. latus in laboratory in comparison to those of Acarius and Sunpyrifos, two chemical acaricides commonly used on vegetable farms in Southern Benin. In addition, their effects on the population densities of the pest and on the productivity of Gboma were evaluated in the field. In the laboratory, mean egg hatching rates varied significantly among treatments, ranging from 36 Â± 5% to 80 Â± 5% (P < 0,0001). The highest hatching rates were recorded with the control and hyptis treatments whereas the lowest hatching rates were recorded with Acarius followed by Sunpyrifos then neem oil treatments. Mortality rates of adult P. latus individuals also varied significantly among treatments, ranging from 43 Â± 2% to 100% (P < 0,0001). The lowest mortality rates were recorded on the control followed by hyptis treatments whereas the highest mortalities were recorded with the double-doses of Acarius, Sunpyrifos and neem oil. In the field trials, mean densities of mobile stages of P. latus varied significantly among treatments, ranging from 5,37 Â± 0,59 to 2,71 Â± 0,37 individus (P < 0,0001). The highest densities were recorded on the control treatment whereas no significant differences were observed among the five other treatmentsThe highest productivities in fresh Gboma leaves on 4 m2 plot were recorded with neem oil (13.65 Â± 2.13 kg), Sunpyrifos (11.1 Â± 1.66 kg) and Acarius (10.76 Â± 1.32 kg). Pending further studies, neem oil may be recommended as an alternative to chemical acaricides for the control of P. latus on Gboma plots in Southern Benin.