Impact of some alternative methods to chemical control in controlling aphids (Hemiptera: Sternorrhyncha) and their side effects on natural enemies on young Moroccan citrus groves

Aphid control in Moroccan citrus orchards is based mainly on carbamate and neonicotinoid sprays, especially methomyl and imidacloprid. The extensive use of these insecticides may have side effects on natural enemies and environment quality and raises human health concerns. This research aimed to assess the control of aphids with insecticidal soap, kaolin and augmentative biological control using the indigenous predator Adalia decempunctata L. (Coleoptera: Coccinellidae). The insecticides were applied and the predators were released in April 2009 and 2010. Under field experimentation, the methomyl and imidacloprid foliar pulverization were very effective against aphids. In contrast, the insecticidal soap and kaolin application were less efficient while A. decempunctata adults were effective only in the first week after release. The side effects on beneficial insects were also assessed and discussed. The possibility of employing A. decempunctata in an integrated pest management package in citrus groves is discussed in relation to effectiveness and side effects on beneficial arthropods.     

Suppression of microRNA-silencing pathway by HIV-1 during virus replication

MicroRNAs (miRNAs) are single-stranded noncoding RNAs of 19 to 25 nucleotides that function as gene regulators and as a host cell defense against both RNA and DNA viruses. We provide evidence for a physiological role of the miRNA-silencing machinery in controlling HIV-1 replication. Type III RNAses Dicer and Drosha, responsible for miRNA processing, inhibited virus replication both in peripheral blood mononuclear cells from HIV-1-infected donors and in latently infected cells. In turn, HIV-1 actively suppressed the expression of the polycistronic miRNA cluster miR-17/92. This suppression was found to be required for efficient viral replication and was dependent on the histone acetyltransferase Tat cofactor PCAF. Our results highlight the involvement of the miRNA-silencing pathway in HIV-1 replication and latency.     

In vitro antibiosensitivity of different strains of Mycoplasma capricolum

The in vitro sensitivity of 20 wild strains of M. capricolum and that of the reference strain (California kid) against 14 antibiotics was investigated by means of a micromethod. The technique is based on the determination of the inhibitory minimum concentration (IMC) in a liquid medium as revealed by the inhibition of glucose metabolism. The following results were obtained: all strains were sensitive to five antibiotics (tylosin, oxytetracyclin, gentamycin, neomycin, nalidixic acid) with an IMC varying from 0.06 to 8 meq/ml. The variation in the IMC values from 8 to 32 meq/ml for spiramycin and erythromycin indicated that some of these strains were sensitive and other resistant to these two drugs. All strains were resistant to seven antibiotics (streptomycin, bacitracin, polymyxin, chloramphenicol, lincomycine, rifampicine and novobiocine), sometimes at a concentration exceeding 128 meg/ml.     

Mining and predictive characterization of resistance to leaf rust (Puccinia hordei Otth) using two subsets of barley genetic resources

Genetic Resources and Crop Evolution - Sustainable barley (Hordeum vulgare L.) production will require access to diverse ex-situ conserved collections to develop varieties with high yields and...