American-Eurasian Journal of Sustainable Agriculture

Number 1, 2013

1-9
Study of the Toxicity of Azadirachtinon Larval Mortalityand Fertility of Carob Moth’s FemaleEctomyeloisceratoniae (Lepidoptera, Pyralidae) Under Controlled Conditions

Authors: 1M.S. Mehaoua, 1A. Hadjeb, 1M. Lagha, 2M.K. Bensalah and 3M.L.Ouakid

Abstract

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Carob moth Ectomyeloisceratoniae Zeller is the most dangerous pests of dates in Algeria. This species is polyphagia, its wide distribution in space and on various hosts make chemical control the most using in palm grove without success. Under these conditions, only the biological control may be able to limit the damage of this pest and reduce the negative effect of chemicals on the environment and fauna life in palm grove. The study of azadirachtin effect on the mortality on the first larval stage revealed that the doses used were significantly and positively correlated with mortality corrected for different durations of exposure of larvae L1 to biopesticide (24 hours: r2 = 0.872; 48 hours: r2 = 0.906; 72 hours: r2 = 0.905; 96 hours:r2 = 0.880 and 120 hours: r2 = 0.779). The higher LD50 (437.59 ppm) was recorded for a lethal time of 24 hours however the lowest LD50 (76.86 ppm) was observed for a lethal time of 120hours. We have also recorded a decrease in female’s fertility issue from larvae’s survived to the treatment withazadirachtin;with an average low lying eggs of54.67±19.41 induced by the doseof 384 ppmand low hatching rate of eggs with 17.51±2.94 % occasion by the dose of 192 ppm, compared at thecontrolwith 159.67 ± 35.04 eggs laid and hatching rate with 94.96±2.53 %. Also thedosesusedwere significantly andnegativelycorrelated with thenumber of laidand hatchedeggs(r2 = 0.755 and r² = 0.712 respectively).

10-13
Serodetection Of Citrus Tristeza Closterovirus(Ctv) In Algeria

Authors: BelkahlaHadjira, Larbi Djamila, Bouafia Lylia, Moudoud Razika, Guettouche Fadhila and Bouzidi Saida

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Surveys on the Citrus TristezaClosterovirus(CTV) and their vectorswere carried out in Algerian citrus fruit areas of Mitidja [station of department of agronomy of Blida (1), Guerrouaou (2), Hadjout (3), Boufarik (4), Mouzaia (5) and Soumaa (6)].Aphis spiraecola was present in three exploitations of citrus fruit areas ofMitidja (2), (5), and (1). WhereasToxopteraaurantiiwas detected only in two exploitations of citrus fruit areas of Mitidja (1), and (5). In most areas CTV-like symptoms i.e. complete deterioration of the trees, yellowing of leaves were observed. Serological tests were done on these crops using DAS-ELISA. CTV was prevalent only in five exploitations of citrus fruit areas of Mitidja (6) (5) (2) (1) (

14-20
Bio-ecology of a citrus pest (Aonidiella aurantii Maskell) (Hemiptera, Diaspididae): spatiotemporalrelationship with its host plants Citruslimon and C.sinensis in Algiers region.

Authors: 1Belguendouz-Benkhelfa R., 2Biche M., 2R. Adda, 3Allal-Benfekih L.

Abstract

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Our prospective analysis in this work is based on a comparative study of bioecological balances of A. aurantii on two Citrus habitats (C. Sinensis var. Washington navel and C. Limon var. Eureka) in Rouiba region east of the Algerian capital Algiers. Our results showed that infestations are high, temporal distributions are most abundant on lemon (77.50%). Our statistical analyzes showed that rainfall, host plant and the evolutionary stage of the pest are the limiting factors for its abundance and its temporal distribution. In our climate conditions, the red scale develops three overlapping generations per year on the two host plants: (1frst) in summer (2nd) in spring and the (3rd) in autumn. This behaviour can be explained by a further study on the influence of trophic factors.

21-26
Comparative evaluation of the toxicity of lambda cyhalothrin and spinosad on the insect pests and auxiliary fauna in an orange orchard of the central Mitidja (Blidean Atlas, Algeria)

Authors: 1Allal-Benfekih L., 1Aoudia B., 1Mostefaoui H. & 2Belguendouz R

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Impact of phytosanitary treatments on time variation in the abundance and diversity of the insect fauna was evaluated on an orange orchard in Central Mitidja. The ecotoxicity of Lambda-cyhalothrin and spinosad applied to the approved dose and half-dose were evaluated through the abundance and availability of pest populations and associated auxiliary procession after a period of 16 days exposure. Our results showed that Lambda-cyhalothrin has a toxic effect on the aphid residual population during 12 days after treatment, which is moderately toxic from the 13th to the 16th day, while spinosad has a neutral effect during the hole exposure period. Community of the insect fauna harvested during the 16 days of observation after treatment consists of 12 species of phytophagous, 11 parasits and 13 predators. Under the effect of the approved dose of Lambda-cyhalothrin, temporal fluctuation pest shows a slight increase in the first 12 days with a significant difference compared to control (23.30% in 12 days). The Aphididae, Phyllocnistis citrella and Ceratitis capitata are the most influenced unlike Coccidae, Aleurodidae and Tetranychus sp. The similarity analysis to one factor shows very highly significant differences between two types of treatments and between each treatment group and the controls. These differences may be due to variations in the relative abundance of different taxa or species composition of communities. Lowest contribution differences are recorded in parasitoïds and Chrysopidae. Key words: pesticides, ecotoxicology, beneficial ennemis, pests, crops, auxiliary fauna assemblages.