Development of citrus fruit fly control strategies for small-holders in Nigeria.Abstract --Introduction. Damage of citrus fruits by the Mediterranean fruit fly Ceratitis capitata Weid. results in economic losses in Nigeria. The majority of the citrus producers are smallholders who are yet to adopt standard citrus production practices. A trial was therefore established in a savannah zone of Nigeria with a Southern Guinea agroecology to evaluate simple fruit fly control practices. Materials and methods. The efficacy of combining cultural practices such as removal of dropped fruits, changes of harvest period, and three applications of dimethoate/cypermethrine mixture in controlling fruit fly damage was tested on sweet orange Citrus sinensis (L.) Osbeck var. Valencia Late in 2000 and 2001. Results. Fruits attacked by C. capitata increased with fruit maturity and were positively correlated with the number of dropped fruits. Insecticide applications and removal of dropped fruits significantly reduced the number of fruits attacked by the fruit flies. Similarly, early harvesting at 50% fruit ripening significantly (P < 0.05) reduced the number of fruits attacked by the fruit flies when compared with the late harvesting at 90% ripening. The interactive effects of insecticide applications and the period of harvest significantly (P < 0.05) reduced attacks on fruits. Discussions. Judicious use of insecticides, periods of harvest and removal of fallen fruits reduce fruit fly damage. Late harvest and non-removal of fallen fruits constitute fruit fly reservoirs for the re-infestation of other clean fruits. Since the tested control methods were simple, they can be adopted by small-holders for the control of fruit flies.Nigeria / Citrus / insect control / integrated control / Ceratitis capitata / insecticides / cultivation Développement des méthodes de lutte contre la mouche des agrumes pour les petits cultivateurs au Nigéria.Résumé --Introduction. Les dégâts causés aux agrumes par la mouche des fruits Ceratitis capitata Weid. causent de fortes pertes économiques au Nigeria. La plupart des producteurs d'agrumes sont de petits producteurs qui n'utilisent pas encore de techniques de production appropriées. Pour cette raison, des essais ont été établis pour évaluer des méthodes de lutte simples contre la mouche des fruits dans la savane d'une zone du Nigeria ayant une écologie sudguinéenne. Matériel et méthodes. L'efficacité de la combinaison de pratiques culturales, telles que le ramassage des fruits tombés, la modification de la période de récolte et l'application d'un mélange de diméthoate/cyperméthrine, contre les dégâts de mouches des fruits sur oranges Citrus sinensis (L.) Osbeck var. Valencia Late a été évaluée en 2000 et 2001. Résultats. Le nombre de fruits attaqués par C. capitata a augmenté avec la maturation des fruits et il a été positivement corrélé aux nombres de fruits tombés. Les traitements insecticides et l'élimination des fruits tombés ont significativement réduit le nombre de fruits attaqués par les mouches. De ...

The volatile oils extracted from leaves of eight cultivars of Citrus sinensis (L) Osbeck were comprehensively analysed by a combination of GC and GC-MS. Fifty four constituents accounting for 82.3-98.2% were identified. Sabinene (20.9-49.1%), δ-3-carene (0.3-14.3%), (E)-β-ocimene (4.4-12.6%), linalool (3.7-11.1%) and terpinen-4-ol (1.7-12.5%) were the major constituents that are common to all the volatile oils. In addition, a cluster analysis was carried out and indicated at least four different chemotypes for the C. sinensis cultivars.

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