Abstract

In order to limit the devastation caused in the celery (Apium graveolens L., 1753) plots by Liriomyza trifolii Burgess in Nkolondom, (Southern Cameroon), farmers proceed to the anarchic use of synthetic insecticides in addition to the pruning of the infested leaves as sanitary harvests. These infested leaves resulting from sanitary harvests are immediately abandoned in the furrows. The main objective of the present study was to assess the efficiency of pruning as a control method versus L. trifolii. The durations of the development of the pre-imaginal stages, the fitness and the sex-ratio of L. trifolii we are were evaluated using both whole plants and pruned parasitized leaves, respectively in the laboratory and the celery plot during the warm-dry and cold-humid seasons. The results obtained showed that the average duration of the pre-imaginal development cycle of L.trifolii varied between 16.53 ± 0.26 days in the laboratory with cut leaves during warm-dry period to 21.98 ± 0.3 days with entire plants in the garden during cold-humid period. It was also shown that from infested cut leaves emerged leafminers were able to cause serious damages to healthy celery plants in the plot. No significant difference was observed between the cut leaves sex ratio (1/0.96) and that of the whole plants (1/0.91); (χ² = 2.38; df = 1; P=0.12). The L. trifolii sex ratio which is slightly biased toward females was not affected by the food resource.

Key words: Apium graveolens, Liriomyza trifolii, leafminer, pruning, sex ratio, fitness.