%0 Journal Article
%T Management of African root and tuber scale using improved cassava genotypes and mineral fertilisers
%A KM Lema
%A K Tata-Hangy
%A M Bidiaka
%J African Crop Science Journal
%D 2004
%I 
%X The African root and tuber scale (ARTS), Stictococcus vayssierei Richard, is an insect species indigenous to Africa, which has recently become an economic pest of cassava (Manihot esculenta Crantz) in many parts of the Democratic Republic of the Congo (D R C). This scale infests underground parts of the plants and prevents young plants from tuberising, thus, causing yield losses of up to 100%. In order to evaluate control components that can be combined into an effective strategy for the management of the scale, six improved cassava genotypes were evaluated for resistance against the scale and NPK fertiliser was tested at the recommended rate as a pest control component. The fertiliser application was made as basal dressing and on one improved clone (F100) with a local variety. Results indicated that ARTS infestations were delayed on ¡®Kinuani', F100 and the local clone, ¡®Kileba', as no scales were observed on them 6 months after planting (MAP). The sweetest improved genotype, ¡®Papayi', harboured the highest number (134.8 insects plant-1) of scales. At 9 and 12 (harvest) MAP, all clones were relatively highly infested, except for the bitter genotype, ¡®Sadisa'. This clone also yielded more than the local clone. Mineral fertiliser application significantly increased scale population density on F100, and plant height on both F100 and the local clone. It did not significantly affect the number of tuberous roots and root yield on either the improved F100 or on ¡®Kileba'. Key Words: Democratic Republic of Congo, Manihot, Stictococcus vayssierei R¨¦SUM¨¦ La gamme des racines et tubercules Africains, Stictococus vayssierei Richard, est une esp¨¨ce indig¨¨ne ¨¤ l'Afrique qui est r¨¦cemment devenue une peste ¨¦conomique de manioc (Manihot esculenta Crantz) dans beaucoup d'endroits de la R¨¦publique D¨¦mocratique du Congo (RDC). Cette gamme infecte les parties souterraines des plantes et emp¨ºche les jeunes plantes ¨¤ former les tubercules, causant ainsi des pertes de rendements jusqu\'¨¤ 100%. En vue d'¨¦valuer les composants de contr le qui peuvent ¨ºtre combin¨¦s dans une strat¨¦gie effective pour la gestion de la gamme, six g¨¦notypes am¨¦lior¨¦s de manioc ¨¦taient ¨¦valu¨¦s pour la r¨¦sistance contre la gamme et le fertilisant NPK ¨¦tait test¨¦ au taux recommand¨¦ comme un composant de d¨¦sinsectisation. L'application de fertilisant ¨¦tait faite comme engrais fondamental et sur un clone am¨¦lior¨¦ (F100) avec une vari¨¦t¨¦ locale. Les r¨¦sultats ont indiqu¨¦ que les infestations de la gamme des racines et tubercules Africains ¨¦taient retard¨¦es sur ¡® Kinuani', F100 et le clone local, ¡®kileba', ¨¦tant donn¨¦ qu'aucune gamme n'¨¦tait observ¨¦e sur eux 6 mois apr¨¨s plantations (MAP). Le g¨¦notype am¨¦lior¨¦ le plus sucr¨¦, ¡®Papayi', a h¨¦berg¨¦ le nombre le plus ¨¦lev¨¦ (134,8 insectes plante-1) de gamme. A 9 et 12 mois (r¨¦colte) MAP, tous les clones ¨¦taient relativement gravement infect¨¦s, ¨¤ l'exception du g¨¦notype am¨¨re, ¡®Sadisa'. Ce clone a aussi produit plus que le clone local. L'application de fert
%U http://www.ajol.info/index.php/acsj/article/view/27881