Effect of climate change on stormwater runoff characteristics and treatment efficiencies of stormwater retention ponds; a case study from Denmark using TSS and Cu as indicator pollutants. SpringerPlus, 5:1984, 1-12.

This study investigated the potential effect of climate changes on stormwater pollution runoff characteristics and the treatment efficiency of a stormwater retention pond in a 95 ha catchment in Denmark. An integrated dynamic stormwater runoff quality and treatment model was used to simulate two scenarios: one representing the current climate and another representing a future climate scenario with increased intensity of extreme rainfall events and longer dry weather periods. 100-year long high-resolution rainfall time series downscaled from regional climate model projections were used as input. The collected data showed that total suspended solids (TSS) and total copper (Cu) concentrations in stormwater runoff were related to flow, rainfall intensity and antecedent dry period. Extreme peak intensities resulted in high particulate concentrations and high loads but did not affect dissolved Cu concentrations. The future climate simulations showed an increased frequency of higher flows and increased total concentrations discharged from the catchment. The effect on the outlet from the pond was an increase in the total concentrations (TSS and Cu), whereas no major effect was observed on dissolved Cu concentrations. Similar results are expected for other particle bound pollutants including metals and slowly biodegradable organic substances such as PAH. Acute toxicity impacts to downstream surface waters seem to be only slightly affected. A minor increase in yearly loads of sediments and particle-bound pollutants is expected, mainly caused by large events disrupting the settling process. This may be important to consider for the many stormwater retention ponds existing in Denmark and across the world

Incorporation of lyophilized leaves and pods into artificial diet to assess antibiosis component of resistance to pod borer in pigeonpea

Helicoverpa armigera, is the most damaging insect pest of grain legumes including pigeonpea in the semi-arid tropics, and host plant resistance is an important component for the management of this pest. Because of the variation in insect density over space and time, it is difficult to assess the contribution of different components of resistance to this insect under field conditions. Therefore, we standardized a bioassay involving incorporation of lyophilized leaves or pods into the artificial diet to assess antibiosis component of resistance to H. armigera. Antibiosis was assessed in terms of larval mortality, larval and pupal weights, adult emergence, and duration of development on fresh leaves, flowers and pods, and through incorporation of lyophilized leaves and pods of different pigeonpea genotypes into the artificial diet. Incorporation of 10 g of lyophilized leaf or pod powder into the artificial diet (300 ml) of diet resulted in maximum differences in survival and development of H. armigera larvae on the resistant (ICPL 332) and susceptible (ICPL 87) genotypes. Reduced larval and pupal weights, and prolongation of larval and pupal development periods were observed in insects reared on intact leaves or pods of ICPL 332, ICPL 84060, ICP 7035, ICPL 88039 and T 21. Similar effects were also observed in larvae reared on artificial diet impregnated with lyophilized leaves or pods of ICPL 332, ICPL 84060, ICP 7035, ICPL 187-1, ICPL 88039, and ICP 7203-1. Larval and pupal periods, pupal weight, and pupation and adult emergence were positively correlated between the insects reared on fresh leaves or pods, and on artificial diets impregnated with lyophilized leaves or pods. However, there was no correspondence in terms of larval weight and mortality between the fresh plant parts and diet impregnation assay. Incorporation of lyophilized leaves or pods of pigeonpea into artificial diet for assessing the antibiosis component of resistance to H. armigera has been discussed

Stability of resistance to pod borer, Helicoverpa armigera in pigeonpea

Because of increasing difficulties in controlling the damage by the pod borer, Helicoverpa armigera in pigeonpea with synthetic insecticides, it is important to identify genotypes with resistance to this pest for use in integrated pest management. Therefore, we evaluated a set of 12 diverse genotypes for resistance to H. armigera for two years over four plantings under natural infestation. There were significant differences among the genotypes in numbers of eggs and larvae, percentage pod damage, visual damage rating, and grain yield. The genotypes ICPL 187-1, ICP 7203-1, ICPL 98008, T 21, ICP 7035, and ICPL 332 exhibited moderate levels of resistance to H. armigera across planting dates, although there were a few exceptions. ICPL 187-1, ICP 7203-1, ICPL 84060, ICPL 87119, and ICPL 332 also showed better grain yield potential than the susceptible checks, ICPL 87 and ICPL 87091. All the genotypes were stable in their reaction to pod borer damage based on visual damage rating (except ICPL 87119 and ICPL 84060), but unstable for percent pod damage. Grain yield of most of the genotypes under H. armigera infestation was also unstable, except that of ICPL 87119, ICP 7035, and ICPL 332. Principal component analysis placed the test genotypes into different groups, and there is a possibility of increasing the levels and diversifying the basis of resistance to pod borer, H. armigera