The Weed's News Digest

The Weed's News email digest contains a summary of activity for the time period August 15, 2014 through August 29, 2014.
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The Weed's News Articles

Australia’s pesticide environmental risk assessment failure: The case of diuron and sugarcane

David Low / WeedsNews5110 / August 29, 2014 / 10:35:37 AM EST / 0 Comments
Abstract: In November 2012, the Australian Pesticide and Veterinary Medicines Authority (APVMA) concluded a 12 year review of the PSII herbicide diuron. One of the primary concerns raised during the review was the potential impact on aquatic ecosystems, particularly in the catchments draining to the Great Barrier Reef. The environmental risk assessment process used by the APVMA utilised a runoff risk model developed and validated under European farming conditions. However, the farming conditions in the sugarcane regions of the Great Barrier Reef catchments have environmental parameters beyond the currently validated bounds of the model. The use of the model to assess environmental risk in these regions is therefore highly inappropriate, demonstrating the pitfalls of a one size fits all approach. [Glen Holmes (2014). Australia’s pesticide environmental risk assessment failure: The case of diuron and sugarcane. Marine Pollution Bulletin, online 22 August] Comment

Variation in amphibian respone to glyphosate-based herbicides

David Low / WeedsNews5109 / August 29, 2014 / 10:22:18 AM EST / 0 Comments
Abstract: Variation in toxicity among formulations and species makes it difficult to extrapolate results to all species and all formulations of herbicides. We exposed larval wood frogs (Lithobates sylvaticus) from four populations to two glyphosate-based herbicides, Roundup Weed and Grass Control and Roundup WeatherMax. 96 hour LC50 values for both formulations varied among the populations (RWGC: 0.14 to 1.10 mg acid equivalents (a.e.)/L; RWM: 4.94 to 8.26 mg a.e./L), demonstrating that toxicity varies among the formulations and that susceptibility may differ among populations. [Christopher Edge, Meghan Gahl, Dean Thompson, Chunyan Hao & Jeff Houlaha (2014). Variation in amphibian response to two formulations of glyphosate-based herbicides. Environmental Toxicology and Chemistry, online Aug 16] Comment

Biocontrol of weed in summer rice through grass carp ( Ctenopharyngodon idella )

David Low / WeedsNews5105 / August 28, 2014 / 10:54:18 PM EST / 0 Comments
Abstract: An experiment was conducted in Assam, India with three replications using 2500 fingerlings of grass carp per acre land for controlling weeds in summer rice. Another plot of one acre of summer rice without grass carp was treated as control for comparison. The experiment revealed that while average number of weed and weed weight per m 2 in the rice monoculture (RMC) plot were 28.64 and 25.21 g, respectively; in the integrated rice fish culture (IRFC) plots number and weight of weeds were 3.4 and 2.99, respectively. Grass carp did not consume Echinochloa spp. and Alternanthera spp. Rice pr oduction was 3002 kg grains/acre against 2295 kg/acre, in IRFC and RNC plots, respectively. There was 30.81% increase of rice yield in IRFC, despite of fact that 11.35% the total rice field was used for trench as fish refuse, where rice was not planted. To tal table fish production from IRFC was 2 276.74 kg/acre. The returns from IRFC and RMC were Rs. 20 0775.50 and Rs. 22 950.00 respectively. The BC ratio of IRFC and RMC were 3.05 and 1.48, respectively. The comparative analysis revealed an additional income Rs. 17 7825.50 per acre from IRFC system. From the result of the experiment, it may be concluded that integrating rearing of grass carp with summer rice can be the best tool for controlling weeds. The results revealed that besides controlling the weeds, it also increases rice yield and farm income. Moreover, faecal matters of grass carp add nutrients to the rice field. [Uttam Kumar Baruah, Hira Prabha Rabha & Minakshi Mazumdar (2014). Biocontrol of weed in summer rice through grass carp (Ctenopharyngodon idella. ). Scholars Journal of Agriculture and Veterinary Sciences. 1(3):143-148] Comment

Rolled-crimped winter rye cover effects on hand-weeding times and fruit yield and quality of cucurbits

David Low / WeedsNews5104 / August 28, 2014 / 10:29:28 PM EST / 0 Comments
Abstract: Pesticide-free vegetables are in demand at farmers’ markets featuring locally grown products. Weeds often are deleterious in such crops, and managing them without herbicides is difficult. Stale seedbeds and rolled-crimped winter rye (Secale cereale L.) cover crops are non-chemical methods that may help manage weeds effectively. These methods were compared over two growing seasons as they affected fruit yield, fruit quality, and hand-weeding times in west-central Minnesota for transplanted cucumber (Cucumis sativus L.), pumpkin (Cucurbita pepo L.), and watermelon (Citrullus lanatus [Thunb.] Matsum. &Nakai). Cumulative hand-weeding times were 82-85 hr·ha−1 in stale seedbed systems but 5-18 hr·ha−1in rolled-crimped rye mulch systems. Evenwithout hand-weeding, cucumber yields and quality scores in rye mulch were similar to those in stale seedbeds augmented with preemergence herbicide and hand-weeded. Pumpkin yields were reduced by 25% in rye mulch systems, but quality was not affected. Watermelon had yield reductions up to 75% in rye mulch compared to stale seedbeds with weed control. Cucumber, pumpkin, and watermelon have high, moderate, and low potential, respectively, for herbicide-free production in rolled-crimped winter rye mulch in cold-temperate growing regions. [Frank Forcella, James Eklund & Dean Peterson (2014). Rolled-crimped winter rye cover effects on hand-weeding times and fruit yield and quality of cucurbits. International Journal of Vegetable Science, online 12 August] Comment

Facing the broader dimensions of biological invasions

David Low / WeedsNews5103 / August 28, 2014 / 9:55:19 PM EST / 0 Comments
Abstract: Invasive species are an excellent opportunity to think about the nature society desires, particularly in the face of global changes. Nature and human views of nature are rapidly evolving; our approach to biological invasions through biosecurity institutions and land management policies must evolve in tandem with these changes. We review three dimensions that are insufficiently addressed. First, biological invasions are culturally shaped and interpreted. Humans play a major role in the movement and nurturing of alien life, and esthetics, perception, and emotion are deeply implicated in the management of invasive species. What people fear or regret with invasive species are not their effects on nature per se, but their effects on a particular desired nature, and policymaking must reflect this. Second, biological invasions are not restricted to negative impacts. Invasions take place in landscapes where many natural conditions have been altered, so policy tools must recognize that invasive species are a functional, structural, and compositional part of transformed ecosystems. In some cases, native species benefit from changes in resource availability caused by invasions or from protections provided by an invasive plant. Finally, invasive species can help ecosystems and people to adapt to global change by maintaining ecosystem processes such as productivity, carbon storage, and nutrient cycling in a context of climate change or land cover transformations. While recognition is growing among ecologists that novel, invaded ecosystems have value, and while the on-the-ground application of biosecurity policies has of necessity adjusted to local contexts and other agendas, invasion biology could aid policymaking by better addressing the three complexities inherent in the three dimensions highlighted above. [Jacques Tassin & Christian A. Kull (2014). Facing the broader dimensions of biological invasions. Land Use Policy, 42, 165–169] Comment

Stricter MRLs pushing global demand for biopesticides

David Low / WeedsNews5097 / August 28, 2014 / 2:23:08 PM EST / 0 Comments
[Farm Chemicals International by David Frabotta August 19, 2014] -- Biopesticides have become necessary tools for the preservation of trade around the world. The EU, of course, is leading the way with the establishment of – arguably – arbitrary maximum residue limits that create a de facto global standard. This regulatory reality is driving greater adoption of biopesticides, especially among horticulture producers. Global biopesticide sales are expected to reach $2.8 billion next year, about 4% of the total crop protection market, according to CPL Scientific, an executive-search and business consultancy for companies working in specialty chemicals, biotechnology, animal health, pharmaceuticals and others. CPL estimates the sector will continue to grow 15% per year until 2020, when biological pesticide sales are projected to reach $6.6 billion. | Continue reading … | Comment |