Mobilizing IPM for sustainable banana production in Africa: Proceedings of a workshop on banana IPM held in Nelspruit, South Africa - 23 - 28 November 1998

This 356-page publication is the proceedings of a workshop held in Nelspruit, South Africa in November 1998. Twenty-one valuable communications are included, giving an up-to-date overview on research activities on weevils, nematodes, pathology and farming systems in sub-Saharan Africa. Nine country-case studies are also presented. Working groups' results and recommendations are included. This book will certainly be very useful for all those interested in IPM, especially in Africa

DeepWAS: multivariate genotype-phenotype associations by directly integrating regulatory information using deep learning

Genome-wide association studies (GWAS) identify genetic variants associated with traits or diseases. GWAS never directly link variants to regulatory mechanisms. Instead, the functional annotation of variants is typically inferred by post hoc analyses. A specific class of deep learning-based methods allows for the prediction of regulatory effects per variant on several cell type-specific chromatin features. We here describe "DeepWAS", a new approach that integrates these regulatory effect predictions of single variants into a multivariate GWAS setting. Thereby, single variants associated with a trait or disease are directly coupled to their impact on a chromatin feature in a cell type. Up to 61 regulatory SNPs, called dSNPs, were associated with multiple sclerosis (MS, 4,888 cases and 10,395 controls), major depressive disorder (MDD, 1,475 cases and 2,144 controls), and height (5,974 individuals). These variants were mainly non-coding and reached at least nominal significance in classical GWAS. The prediction accuracy was higher for DeepWAS than for classical GWAS models for 91% of the genome-wide significant, MS-specific dSNPs. DSNPs were enriched in public or cohort-matched expression and methylation quantitative trait loci and we demonstrated the potential of DeepWAS to generate testable functional hypotheses based on genotype data alone. DeepWAS is available at https://github.com/cellmapslab/DeepWAS

Solar Influence on Nuclear Decay Rates: Constraints from the MESSENGER Mission

We have analyzed Cs-137 decay data, obtained from a small sample onboard the MESSENGER spacecraft en route to Mercury, with the aim of setting limits on a possible correlation between nuclear decay rates and solar activity. Such a correlation has been suggested recently on the basis of data from Mn-54 decay during the solar flare of 13 December 2006, and by indications of an annual and other periodic variations in the decay rates of Si-32, Cl-36, and Ra-226. Data from five measurements of the Cs-137 count rate over a period of approximately 5.4 years have been fit to a formula which accounts for the usual exponential decrease in count rate over time, along with the addition of a theoretical solar contribution varying with MESSENGER-Sun separation. The indication of solar influence is then characterized by a non-zero value of the calculated parameter \xi, and we find \xi=(2.8+/-8.1)x10^{-3} for Cs-137. A simulation of the increased data that can hypothetically be expected following Mercury orbit insertion on 18 March 2011 suggests that the anticipated improvement in the determination of \xi could reveal a non-zero value of \xi if present at a level consistent with other data.Comment: Accepted for publication in Astrophysics and Space Science, 2011. 7 pages, 5 figures. Version 2 has corrected Figure 1, since Fig. 1 did not appear correctly in Version

A historical perspective on the discovery of statins

Cholesterol is essential for the functioning of all human organs, but it is nevertheless the cause of coronary heart disease. Over the course of nearly a century of investigation, scientists have developed several lines of evidence that establish the causal connection between blood cholesterol, atherosclerosis, and coronary heart disease. Building on that knowledge, scientists and the pharmaceutical industry have successfully developed a remarkably effective class of drugs—the statins—that lower cholesterol levels in blood and reduce the frequency of heart attacks

The elusive banana weevil Cosmopolites sordidus Germar

The banana weevil Cosmopolites sordidus Germar, has evaded all efforts to manage it in all banana-based cropping systems except the commercial plantation banana system, where the 2 to 3 year crop cycle and the intensity of management limit the pest survival in that system. Conversely, in backyard and subsistence banana systems, predominant in Africa, the perennial cropping of banana and plantain, coupled with the planting of infested material, readily supports the pest survival strategies, resulting in pest build-up and crop losses. This hypothesis may explain why the banana weevil has eluded control in perennial banana cropping systems. This review article provides a summary of available literature on weevil pest management strategies with the intent of identifying loopholes in the conceptualization of the problem and possible research information gaps in the current management activities. The review attributes current weevil pest management problems to the poor understanding of the linkages between weevil biology and associated ecological strategies, as well as the broad banana and plantain systems and human activities. This review article urges that the solution to the weevil pest problems lies in the careful integration of biological applications and socioeconomic strategies in the context of the broad ecological farming systems

Nutrient Flows From Harvested Banana Pseudostems

Management of harvested (senescent) banana pseudostems has implications for efficiency of nutrient use for sole cropped as well as intercropped bananas. Two studies were conducted on aspects of nutrient flows from senescent pseudostems. Sixty one and 55% of the initial N and P, respectively, in standing senescent pseudostems were determined to be translocated to attached growing pseudostems at six weeks after harvest. Lesser proportions of the initial K, S, Fe, Zn, Cu and B were translocated; translocation of Ca, Mg and Mn was negligible. Over 50% and 70% of the initial N, K and Mg were released from the mulch of cut and shredded pseudostems by six and nine weeks after harvest, respectively. Other nutrients were released more slowly from the mulch

Nutrient Flows From Harvested Banana Pseudostems

Management of harvested (senescent) banana pseudostems has implications for efficiency of nutrient use for sole cropped as well as intercropped bananas. Two studies were conducted on aspects of nutrient flows from senescent pseudostems. Sixty one and 55% of the initial N and P, respectively, in standing senescent pseudostems were determined to be translocated to attached growing pseudostems at six weeks after harvest. Lesser proportions of the initial K, S, Fe, Zn, Cu and B were translocated; translocation of Ca, Mg and Mn was negligible. Over 50% and 70% of the initial N, K and Mg were released from the mulch of cut and shredded pseudostems by six and nine weeks after harvest, respectively. Other nutrients were released more slowly from the mulch

Biology and integrated pest management for the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae)

The banana weevil Cosmopolites sordidus (Germar) is the most important insect pest of bananas and plantains (Musa spp.). The larvae bore in the corm, reducing nutrient uptake and weakening the stability of the plant. Attack in newly planted banana stands can lead to crop failure. In established fields, weevil damage can result in reduced bunch weights, mat die-out and shortened stand life. Damage and yield losses tend to increase with time. This paper reviews the research on the taxonomy, distribution, biology, pest status, sampling methods, and integrated pest management (IPM) of banana weevil. Salient features of the weevil's biology include nocturnal activity, long life span, limited mobility, low fecundity, and slow population growth. The adults are free living and most often associated with banana mats and cut residues. They are attracted to their hosts by volatiles, especially following damage to the plant corm. Males produce an aggregation pheromone that is attractive to both sexes. Eggs are laid in the corm or lower pseudostem. The immature stages are all passed within the host plant, mostly in the corm. The weevil's biology creates sampling problems and makes its control difficult. Most commonly, weevils are monitored by trapping adults, mark and recapture methods and damage assessment to harvested or dead plants. Weevil pest status and control options reflect the type of banana being grown and the production system. Plantains and highland bananas are more susceptible to the weevil than dessert or brewing bananas. Banana production systems range from kitchen gardens and small, low-input stands to large-scale export plantations. IPM options for banana weevils include habitat management (cultural controls), biological control, host plant resistance, botanicals, and (in some cases) chemical control. Cultural controls have been widely recommended but data demonstrating their efficacy are limited. The most important are clean planting material in new stands, crop sanitation (especially destruction of residues), agronomic methods to improve plant vigour and tolerance to weevil attack and, possibly, trapping. Tissue culture plantlets, where available, assure the farmer with weevil-free material. Suckers may be cleaned by paring, hot water treatment and/or the applications of entomopathogens, neem, or pesticides. None of these methods assure elimination of weevils. Adult weevils may also invade from nearby plantations. As a result, the benefits of clean planting material may be limited to a few crop cycles. Field surveys suggest that reduced weevil populations may be associated with high levels of crop sanitation, yet definitive studies on residue management and weevil pest status are wanting. Trapping of adult weevils with pseudostem or corm traps can reduce weevil populations, but material and labour requirements may be beyond the resources of many farmers. The use of enhanced trapping with pheromones and kairomones is currently under study. A combination of clean planting material, sanitation, and trapping is likely to provide at least partial control of banana weevil. Classical biological control of banana weevil, using natural enemies from Asia, has so far been unsuccessful. Most known arthropod natural enemies are opportunistic, generalist predators with limited efficacy. Myrmicine ants have been reported to help control the weevil in Cuba, but their effects elsewhere are unknown. Microbial control, using entomopathogenic fungi and nematodes tend to be more promising. Effective strains of microbial agents are known but economic mass production and delivery systems need further development. Host plant resistance offers another promising avenue of control. Numerous resistant clones are known, including Yangambi-km 5, Calcutta 4, and Pisang awak. Resistance is most often through antibiosis resulting in egg or larval failure. Banana breeding is a slow and difficult process. Current research is exploring genetic improvement through biotechnology techniques including the introduction of foreign genes. Neem has also shown potential for control of banana weevil. Studies on the use of other botanicals against banana weevil have failed to produce positive results. Chemical control of banana weevil remains a common and effective method for larger scale producers but is beyond the reach of resource-poor farmers. However, the weevil has displayed the ability to develop resistance against a broad range of chemicals. In summary, cultural control remains the most available approach for resource-poor farmers. A combination of several cultural methods is likely to reduce weevil pressure. Among the methods currently under study, microbial control, host plant resistance and neem appear to offer the most promise