Occurrence and incidence of stored product insects on cassava chips in storage in Central and Southern regions of Cameroon: Central Africa

Présence et incidence des insectes des produits en stocks sur les cossettes de manioc en stockage dans les régions centrales et méridionales du Cameroun: Afrique centrale

BOYOMO ONANA1, ANNA A ENO1,  ESSONO G1*, AMBANG A2, AYODELE M3

1University of Yaoundé I: Faculty of Science, Department of Microbiology, P.O. Box, 812 Yaoundé, Cameroon; 2University of Yaoundé I: Faculty of Science, Department of Plant biology, P.O. Box, 812 Yaoundé, Cameroon; 3International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria.

(*Corresponding author: E-Mail: germain_gabriel@live.fr; Tel: (237) 674275731)

Received July, 2015; revised July, 2016; accepted August, 2016.

ABSTRACT

Quantitative and qualitative surveys of stored product insects infesting stored cassava chips were carried out in 45 villages in the southern part of Cameroon. Out of 132 samples of cassava chips collected, 25 contained some insects. The insects detected included 6 species in 2 orders (Coleoptera, and Dictyoptera). The level of insect infestation in a given sample varied between 1 and 20 individuals per 100g of cassava chips. Sitophilis zeamais Motschulsky (Coleoptera: Curculionidae) infested more than half of the insect positive samples, and formed 30 % of the total insect population. It was therefore considered as the dominant and constant species. The presence of Periplaneta americana L. (Dictyoptera: Blatidae) was marginal in all insect positive samples. The level of insect infestation was not significantly related to the locations of sample collection and to moisture content, but to types of chips (P < 0.05). The present study raises awareness on insects as potential carriers of toxigenic fungi and mycotocoxin inducing agents in stored cassava chips.

Key words: Stored-product insects; Survey; Cassava chips; Cameroon; Central Africa

 

RESUME

Les enquĂŞtes quantitatives et qualitatives des insectes des produits entreposĂ©s infestant les cossettes de manioc stockĂ©es ont Ă©tĂ© rĂ©alisĂ©es dans 45 Villages dans la partie sud du Cameroun. Sur 132 Ă©chantillons de cossettes de manioc recueillies, 25 contenaient des insectes. Les insectes dĂ©tectĂ©s inclus appartenaient a 6 espèces, 2 Ordresen (Coleoptera, et Dictyoptera). Le niveau d’infestation par les insectes dans un Ă©chantillon donnĂ© variait entre 1 et 20 individus par 100 g de cossettes de manioc. Sitophilis zeamais Motschulsky (Coleoptera: Curculionidae) a infestĂ© plus de la moitiĂ© des Ă©chantillons et reprĂ©sente 30% de la population totale des insectes. Il a donc Ă©tĂ© considĂ©rĂ© comme l’espèce dominante et constante. La prĂ©sence de Periplaneta americana L. (Dictyoptera: Blatidae) Ă©tait marginale dans tous les Ă©chantillons contenant les insectes. Le niveau d’infestation par les insectes n’a pas Ă©tĂ© significativement liĂ©e aux lieux de collecte d’Ă©chantillons et Ă  l’humiditĂ© contenu, mais Ă  des types de cossettes (p <0,05). La prĂ©sente Ă©tude vise Ă  sensibiliser sur le rĂ´le des insectes comme vecteurs potentiels de champignons toxigènes et des agents inducteurs de mycotocoxine dans les cossettes de manioc stockĂ©es.

Mots clés: Insectes des stocks; enquête; cossettes de manioc; Cameroun; Afrique centrale.