Damage on sweet orange fruits by the mitePolyphagotarsonemus latus(Banks) and the population of its predatory mites in Southwestern Nigeria

Abstract

Damage on sweet orange fruits by the mite Polyphagotarsonemus latus (Banks) and the population of its predatory mites in Southwestern Nigeria. Abstract-Introduction. Scars and blemishes on citrus fruits render them unacceptable to prospective local buyers as well as the export market. To ameliorate this situation, the populations of the phytophagous mite Polyphagotarsonemus latus Banks (one of the agents at the origin of the damage observed) and its predatory mites were assessed in an orchard in the National Horticultural Research Institute (NIHORT), Ibadan, Nigeria, during the 2000 and 2001 fruiting seasons. The damage inflicted upon the fruits of 12 varieties of orange trees was studied jointly. The aim of the study was to identify appropriate periods to initiate control and to assess varietal effects on mite attack. Materials and methods. Twelve varieties of sweet oranges arranged in a randomized complete block design with four replications were used for the study. A stand of each variety was sampled per replicate to assess mite population and damage. Results and discussion. Mite populations and their damage on sweet orange varieties increased to fruit maturity. Washington Navel, Valencia Late, Agege and Lue Gin Gong varieties were most susceptible to mite attack and recorded higher fruit damage than the other varieties. The populations of the predominant predatory mites (the Bdellidae family) that attacked P. latus were significantly (P < 0.05) correlated with their prey at high population periods. The detrimental effects of pesticide overuse on natural enemies were highlighted. Conclusion. The progressive increase in mite population suggests the need for initiating control of phytophagous mites in July before the peak population period of September for Nigeria. Nigeria / Citrus sinensis / variety trials / fruits / Polyphagotarsonemus latus / pest mites / pest control Dégâts de Polyphagotarsonemus latus à la production d'oranges du sudouest nigérian et étude de ses parasitoïdes. Résumé-Introduction. Les cicatrices et les défauts des agrumes les rendent inaptes à la vente locale et au marché d'exportation. Pour améliorer cette situation, les populations de l'acarien phytophage P. latus Banks (l'un des agents à l'origine des dégâts observés) et de ses parasitoïdes ont été évaluées dans un verger de l'Institut de recherche horticole national (NIHORT), à Ibadan, Nigéria, pendant les saisons de production 2000 et 2001. Conjointement, les dommages infligés aux fruits de 12 variétés locales d'oranger ont été étudiés. Le but de notre étude a été d'identifier les meilleures périodes de contrôle de l'acarien et d'évaluer la sensibilité des différentes variétés d'oranger à l'attaque de l'insecte. Matériel et méthodes. Douze variétés d'orange douce placées selon un dispositif en blocs complets randomisés, avec quatre réplications, ont été utilisées pour notre étude. Un représentant de chaque variété a été échantillonné par réplication pour évaluer la population du phytophage et ses dommages. Résultats et discussion. Les ...

Population Dynamics of Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) on Common Potato Cultivars in Egypt.

“…Most of the investigations concluded that different cultivars were susceptible to the mite P. latus, however at varying levels viz. in potato (Kamlesh and Luthra, 2007), Jute (Yadav and Adbhut, 2010), mulberry trees (Zhang et al 1990), sesame (Ahuja and Kalyan, 2001), cotton (Gossypium hirsutum) (Vieira et al, 2002), eggplant (Gui et al, 2001), cucumber (Grinberg et al, 2005) and sweet orange plants (Umeh et al, 2007). The difference in the susceptibility of different potato cultivars observed in the present study to infestation by P. latus may be due to change of phytochemical components in the leaves, physical and anatomical characters and genetic variability to pest resistance.…”