Transgenic plants expressing immunosuppressive dsRNA improve entomopathogen efficacy against Spodoptera littoralis larvae

Journal of Pest Science - Transgenic plants that express double-stranded RNA (dsRNA) targeting vital insect genes have recently emerged as a valuable new tool for pest control. In this study,...     

Parasitic phase of Anocentor nitens (Acarina: Ixodidae) in cattle

The parasitic phase of Anocentor nitens (Neumann) in cattle was studied. Larval stage was present up to 15 days post-infestation (p.i.), concomitant with nymphae from day 8 p.i. Nymphae were observed up to day 23 p.i., adults being seen from day 15 p.i. onwards. Male ticks disclosed active movements from day 17 p.i. and detachment of engorged females began 22 to 24 days p.i. Massive detachment occurred from day 28 p.i. Preferential sites of parasitic stages were ear and neck (lateral side).     

Comparison of three serological tests for Brucella ovis infection of rams using different antigenic extracts

The sensitivity and specificity of the complement fixation, gel diffusion and ELISA tests for the diagnosis of Brucella ovis infection of rams have been compared using three different antigenic preparations. The antigens obtained by petroleum ether - chloroform - phenol, or cold saline extractions gave poorer diagnostic results than those obtained by hot saline extraction in all the tests. The best sensitivity was obtained with the ELISA (97.6 per cent) followed by the gel diffusion (96.4 per cent) and complement fixation tests (92.7 per cent). The gel diffusion test detected as positive the two rams negative in the ELISA, while the complement fixation test did not improve the sensitivity of the other tests. Under these conditions all the tests were 100 per cent specific when testing sera from rams free of B ovis.     

Efficacy of long-acting oxytetracycline alone or in combination with streptomycin for treatment of Brucella ovis infection of rams

Twenty-four rams inoculated with Brucella ovis by conjunctival and preputial routes were treated with a long-acting oxytetracycline alone or in combination with dihydrostreptomycin sulfate. The combined treatment eliminated Brucella ovis from 11 of 12 (91.6%) treated rams. Only 4 of 12 (33.3%) rams treated with oxytetracycline alone were bacteriologically negative. Neither treatment resolved clinical epididymitis in 2 rams affected before treatment. Many rams had pathologic lesions in the epididymis and ampullae, which limited the efficacy of antibiotic treatment.     

Host range ofCercospora piaropi andAcremonium zonatum, potential fungal biocontrol agents for waterhyacinth in Mexico

The host ranges ofCercospora piaropi andAcremonium zonatum, fungi native to Mexico and pathogens of waterhyacinth(Eichhornia crassipes), were evaluated using 31 plant species (some with several cultivars tested) representing 22 families of economic and ecological importance. The results showed that only waterlettuce(Pistia stratiotes), another abundant weed in Mexico, was infected byC. piaropi. The use of those pathogens in the biological control of waterhyacinth would not be expected to affect plants of economic and ecological importance in Mexico.