Importance De Trois Bio-agresseurs (ceratitis Capitata, Virachola Livia Et Epilachna Chrysomelina) Sur Quelques Cultures Dans L’extrême Sud-est Algérien (djanet Et Tamanrasset)

Résumé: The study of the damage caused by the bio-aggressors Ceratitiscapitata, Viracholalivia and Epilachnachrysomelina, as well as the study of some bio-ecological parameters is the subject of this work. The estimation of the damage caused by Ceratitis capitata allowed us to record a rate equal to 42%, 76%, 83.3%, 93.3%, 88.7% respectively for orange, tangerine, fig, apricot and pomegranate trees. Pupation duration of pupae from tangerine varies between 10 and 22 days (mean = 13.0± 1.8 days). It is relatively short for pomegranate pupae with 3 and 14 days (mean = 8.3±2.1 days) and fig pupae with 2 and 12 days (mean = 7.8±2.0 days). While the shortest duration is recorded for apricot pupae with 5 and 9 days (mean = 6.9±1.6 days). Pupae from mandarin have a high emergence rate of up to 100% (mean = 63.4±20.5%), while the lowest values are recorded for apricots, between 13.3% and 50% (mean = 33.8±14.7%). Adults of C. capitata have a very variable life span (p = 0.000) depending on the type of crop. The highest longevity of adults is noted in tangerine with 41 to 70 days (mean = 57.3±12.3 days), while it is moderately low for pomegranates with 9 and 49 days (mean = 26.7±13.1 days) and very short for figs with 3 and 14 days (mean = 5.0±2.8 days). The sex ratio is in favor of females with a rate of 75.9% in adults derived from figs. The study of the damage caused by Viracholalivia shows that pomegranate is the most attacked with frequencies varying between 1 and 15 eggs/fruit for eggs and between 1 and 24 penetrations/fruit for larva penetrations. Acacia nilotica comes second with a variation ranging from 1 to 9 eggs/fruit for eggs laid on fruits and almost the same (1 to 8 penetrations/fruit) for larva penetrations. In the third position came Acacia raddiana with an egg frequency that varies between 1 and 3 eggs/fruit and an attack frequency that varies between 1 and 4 penetrations/fruit for the larva penetrations. In the laboratory, the life cycle of this pest on pomegranate varies between 21 and 29 days with an average of 24.3 ± 2.1 days, adults can live up to 10 days for males and 08 days for females. While in the nature, males can live up to 11 days, females can live up to 16 days. The snake melon is the most attacked by Epilachna chrysomelina with an average attack rate of 31.8%, followed by watermelon with 8.6%, while the melon is the least attacked with a rate of 6.7%. The study of the bio-ecology of Epilachna chrysomelina in the South-East Algeria has shown that the average mating time in the laboratory is 124.9 ±79.7mn. The egg laying size varies between 6 and 40 eggs/ female (mean =18.3 ±11.8 eggs/ female). The average development time of Epilachnachrysomelina from egg to adult is 24.2 ± 4.3 days.

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