The control of Asian rust by glyphosate in glyphosate-resistant soybeans.

BACKGROUND: Glyphosate is a widely used broad-spectrum herbicide. Recent studies in glyphosate-resistant (GR) crops have shown that, in addition to its herbicidal activity, glyphosate exhibits activity against fungi, thereby providing disease control benefits. In GR wheat, glyphosate has shown both preventive and curative activities against Puccinia striiformis f. sp. tritici (Erikss) CO Johnston and Puccinia triticina Erikss, which cause stripe and leaf rusts respectively. RESULTS: Laboratory studies confirmed earlier observations that glyphosate has activity against Phakopsora pachyrhizi Syd & P Syd which causes Asian soybean rust (ASR) in GR soybeans. The results showed that glyphosate at rates between 0.84 and 1.68 kg ha(-1) delayed the onset of ASR in GR soybeans. However, field trials conducted in Argentina and Brazil under natural infestations showed variable ASR control from application of glyphosate in GR soybeans. Further field studies are ongoing to define the activity of glyphosate against ASR. CONCLUSIONS: These results demonstrate the disease control activities of glyphosate against rust diseases in GR wheat and GR soybeans.

Species of Cercospora associated with grey leaf spot of maize.

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

Africa: the new family planning frontier.

Sub-Saharan Africa will be the family planning frontier of the twenty-first century. Fertility levels and population growth rates are still high, and family planning programs suited to the region are still being developed. Nevertheless, by the end of the twentieth century, fertility transition was under way in Southern Africa and a few countries elsewhere. Successful regional family planning in the twenty-first century will depend upon stronger political leadership, the development of family planning programs that meet the needs of all segments of society and not only currently married women, assistance to the market, and a recognition of the central importance of hormonal methods, especially injectables. Problems include stagnation in economic growth and in child mortality decline, as well as the persistence of the AIDS epidemic.