Bioherbicides: Dead in the water? A review of the existing products for integrated weed management

The intensive use of synthetic herbicides is questioned for many reasons. Bioherbicides, as integrated weed management tools, however, have the potential to offer a number of benefits such as increased target specificity and rapid degradation. Despite the efforts to identify effective bioherbicide agents in laboratory and field, only thirteen bioherbicides are currently available on the market. Since 1980, the number of biopesticides has increased around the world, while the market share of bioherbicides represents less than 10% of all biopesticides. Nevertheless, weed management implemented at the cropping systems scale needs bioherbicides because of legislation to drive weed management away from heavy reliance on chemicals, the global increase in organic agriculture, the need of both organic and conventional agriculture to increase weed control efficiency, concerns about herbicide resistance, and concern from the public about environmental safety of herbicides. Consequently, we review here the existing products on the market and describe their history, mode of action, efficacy and target weeds. This review is unique because we also discuss the role of bioherbicides in integrated weed management: to manage soil weed seedbanks with seed-targeted agents in addition to primary tillage, to increase the efficacy of mechanical weeding because bioherbicides are more effective on seedlings, to increase the suppression effect of crop cultivars by first slowing weed growth, to terminate cover crops particularly in conservation agriculture, and finally to manage herbicide resistant populations.     

Why are wheat yields stagnating in Europe? A comprehensive data analysis for France

The last two decades are witnessing a decline in the growth trend of cereal yields in many European countries. The present study analyses yield trends in France using various sources of data: national and regional statistics, scattered trials, results of agroclimatic models using climatic data. Effects in genetic changes through breeding, agronomy and climate are investigated as possible causes. Our results show that genetic progress has not declined but it was partly counteracted, from 1990 on, by climate change which in general is unfavorable to cereal yields in temperate climates because of heat stress during grain filling and drought during stem elongation. We cannot however, from the decade beginning in 2000, rule out agronomic causes, related to policy and economy, in particular the decline of legumes in the cereal rotations, replaced by oilseed rape and to a lesser extent the decrease in nitrogen fertilization.     

Controversies in the antiphospholipid syndrome: can we ever stop warfarin?

Patients with antiphospholipid syndrome are at increased risk for recurrent arterial and venous thrombosis and therefore benefit from long term warfarin therapy. The optimal duration of warfarin therapy after a first venous thromboembolic event is however a matter of some controversy and many questions remain unanswered. After reviewing and analysing the available evidence, we discuss some common scenarios in everyday clinical practice where treatment decisions are difficult.     

Molecular- and chemo-systematics: do they have a role in agrochemical discovery?

The use of chemosystematics and molecular data for the selection of plants for screening for new agrochemicals are discussed. The paper shows how the use of systematic data for selecting plants for limonoids, diterpenoids and polyhydroxy alkaloids has resulted in the isolation of many biologically active compounds.     

Fantastic yields in the system of rice intensification: fact or fallacy?

The combination of natural resources, genes, weather and management systems largely determines maximum crop yields. Recently, one of those elements was portrayed as the key to releasing hitherto unrecognized, but significant, untapped growth potential in rice. That element, the system of rice intensification (SRI), is an unconventional management system developed in Madagascar, where it was reported to increase rice yields to ‘fantastic’ levels. To investigate the general potency of the SRI, we conducted experiments in three locations in China comparing yields in conventional and SRI management systems. In addition, we used a theoretical model to predict maximum yields and compared those with reported yields for various locations, including China and Madagascar. Our results imply that the SRI has no inherent advantage over the conventional system and that the original reports of extraordinary high yields are likely to be the consequence of error.     

Yellow sticky traps for decision-making in whitefly management: What has been achieved?

Yellow sticky traps (YSTs) are a key component of IPM programmes for several greenhouse pests. The development of YST-based decision-making tools, e.g. sampling protocols and economic thresholds (ETs), however, has been limited. This review assesses to what extent YST-counts comply with the four criteria of effective sampling (reliability, representativeness, relevance and practicality) as described by Binns et al. (2000) in an attempt to understand the feasibility of designing YST-based decision-making tools for managing whiteflies in greenhouse crops, particularly tomato (Lycopersicon esculentum Mill) and cucumber (Cucumis sativus L.). Many factors are known to affect whitefly flight behaviour and thus, trap catches. The possibility of manipulating such factors to improve YST efficiency and reliability or of interpreting whitefly catches in YSTs with automated tools is discussed. A few studies have shown the correlation between trap and direct visual pest counts from plants. These studies are discussed in the context of whiteflies and trap densities to enhance the representativeness of sampling with YSTs. Relevance implies that the results of sampling reflect crop loss to a sufficient degree. Only few YSTs-based action thresholds have been suggested in the literature, particularly for use with chemical control. There are a number of approaches and technological innovations that can improve the practicality of YSTs by decreasing the effort and time associated with counting insects, a method to facilitate the identification of species in mixed populations on the trap, and sampling methods such as sequential sampling for calculating appropriate sample size, which have been already put in practice to develop YSTs-based sampling protocols. Knowledge gaps are identified and discussed, and a route map for further research to advance YSTs as a decision-making tool is outlined, with geostatistical methods as the recommended approach for further increasing the usefulness of YSTs-based decision-making.     

Fake spawns and floating particles: a rebuttal of Karkarey et al. “Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation”

Courtship and spawning behaviors of coral reef fishes are very complex, and sufficient sampling effort and proper methods are required to draw informed conclusions on their mating systems that are grounded in contemporary theories of mate choice and sexual selection. We reviewed the recent study by Karkarey et al. (BMC Ecol 17:10, 2017) on the spawning behavior of Squaretail coralgrouper (Plectropomus areolatus) from India and found no evidence to support their findings of alternative reproductive tactics, unique school-spawning involving a single male with multiple females, or inverse size-assortment. The study lacks scientific credibility due to a lack of rigor in the methodology used, misinterpretation of observed behaviors, misinterpretation of the literature, and insufficient data. Their approach led the authors to produce spurious results and profound, invalid conclusions that violate the most basic assumptions of mate choice and sexual selection theory as applied to mating systems in marine fishes.     

Hepatotoxic Seafood Poisoning (HSP) Due to Microcystins: A Threat from the Ocean?

Cyanobacterial blooms are a major and growing problem for freshwater ecosystems worldwide that increasingly concerns public health, with an average of 60% of blooms known to be toxic. The most studied cyanobacterial toxins belong to a family of cyclic heptapeptide hepatotoxins, called microcystins. The microcystins are stable hydrophilic cyclic heptapeptides with a potential to cause cell damage following cellular uptake via organic anion-transporting proteins (OATP). Their intracellular biologic effects presumably involve inhibition of catalytic subunits of protein phosphatases (PP1 and PP2A) and glutathione depletion. The microcystins produced by cyanobacteria pose a serious problem to human health, if they contaminate drinking water or food. These toxins are collectively responsible for human fatalities, as well as continued and widespread poisoning of wild and domestic animals. Although intoxications of aquatic organisms by microcystins have been widely documented for freshwater ecosystems, such poisonings in marine environments have only occasionally been reported. Moreover, these poisonings have been attributed to freshwater cyanobacterial species invading seas of lower salinity (e.g., the Baltic) or to the discharge of freshwater microcystins into the ocean. However, recent data suggest that microcystins are also being produced in the oceans by a number of cosmopolitan marine species, so that Hepatotoxic Seafood Poisoning (HSP) is increasingly recognized as a major health risk that follows consumption of contaminated seafood.     

Starch Digestion in Infants: An Update of Available In Vitro Methods—A Mini Review

Plant Foods for Human Nutrition - Complementary feeding starts at around six months of age because neither breast milk nor formula assure the proper nutrition of infants. Therefore, along...     

Threshold-based interventions for cotton pest control in West Africa: What's up 10 years later?

In the late 1980s, after a long period during which insecticides were sprayed at preset dates to control cotton (Gossypium hirsutum L.) pests and their damage, some French-speaking countries in sub-Saharan areas decided to disseminate a special form of crop protection approach among smallholders, i.e. targeted staggered control (LEC, for Lutte étagée ciblée). According to this approach, decisions on some insecticide applications were made on the basis of infestation levels or the extent of crop injury caused by major pests: Aphis gossypii Glover aphids, Haritalodes (=Syllepte) derogata F., leaf-eating caterpillars, and more generally Helicoverpa armigera (Hübner), Diparopsis watersi Rothschild, Earias insulana (Boisduval) and Earias biplaga (Walker) bollworms. Polyphagotarsonemus latus (Banks) mites were sometimes included on this list. Today, the calendar-based or conventional program is still widely implemented with some changes in insecticides applied due to the development of pyrethroid resistance in H. armigera. Depending on the country, protection programs based on pest monitoring have been preserved or replaced by programs still using thresholds (staggered or true). In Benin, there are two forms of LEC tailored to two regions delineated according to the extent of damage caused by of bollworms that live inside cotton bolls, i.e. Thaumatotibia (=Cryptophlebia) leucotreta (Meyrick). The logical follow-up to LEC, involving true thresholds, was developed in Mali, Cameroon and, recently, Senegal. Cameroon opted for a sequential plan for individual decision program or LOIC (for Lutte après observation individuelle des chenilles), based on control after sequential sampling of bollworms. A calendar program with additional applications of insecticides based on a particular scouting of H. armigera was developed in Togo. In Ivory Coast, the use of true thresholds is limited to the beginning of the cotton crop cycle whereas in Burkina Faso true thresholds are used after the first two calendar sprayings. The present article describes the diversity of these cotton protection programs, sampling methods and associated intervention thresholds based on pests or injury levels in addition to the advantages and constraints associated with their adoption.     

The role of gluten in a sugar-snap cookie system: A model approach based on gluten–starch blends

The cookie making properties of dough made from blends of commercial wheat starch and gluten were determined. Higher gluten levels decreased dough piece weight, its density, stickiness and hardness. The largest spread was obtained when no gluten was added. However, this resulted in cookies of unacceptable structure. Higher gluten contents increased spread onset time, decreased cookie spread but generally had little impact on set time while additional water lowered spread onset time and likewise had no statistically significant impact on set time. The results showed that the final cookie diameter is quite dependent on the spread onset time which itself depends on the amount of water available to the non-gluten constituents in the system. Size-exclusion high performance liquid chromatography showed that during baking, proteins aggregated. This indicated that during the process the added gluten acquired the necessary mobility for interaction. However, because increasing levels of gluten increasingly decreased the relative level of water available to itself, and because the set time, and, hence, the set temperature, did not depend on the gluten level, we concluded that cookie dough setting was not determined by an ‘apparent’ glass transition. Furthermore, more protein aggregation went hand in hand with less spread.     

Can the cropping schedule of rice be adapted to changing climate? A case study in cool areas of northern Japan

Adaptation of cropping schedules in response to climate change is essential for increasing rice productivity. In the present study, we analyzed yield, cropping schedule and cultivar characteristics records from 1958 to 2007 in a case study of four prefectures in northern Japan, where low temperatures can severely limit rice growth. Grain yield in all prefectures increased over time, with a higher increase from 1958 to 1982 (2.4 g m⁻² y⁻¹) than from 1983 to 2007 (1.0 g m⁻² y⁻¹). The transplanting date became 0.07–0.91 days y⁻¹ earlier before 1983, but did not appear to change thereafter. The growing period duration from transplanting to harvesting increased over time, especially during the first 25 years. We observed a significant correlation between grain yield and transplanting date before 1983. The length of the potential growing period, defined as the period from the earliest potential date for transplanting and the latest potential date for harvesting, increased over time in all four prefectures. The gap between the actual growing period and the potential growing period increased after 1983. The safe reproductive period, which is defined as the duration within which rice can escape cold damage during its reproductive stage, did not appear to change over time. Based on these results, we discuss future cropping schedules capable of increasing rice productivity under a changing climate in the future.     

Trade-off between oil and protein in rapeseed at high latitudes: Means to consolidate protein crop status?

Crop-derived feed protein production is alarmingly low in Europe. Finland represents the northernmost growing region in the world and consequently lacks wide-ranging alternatives to improve crop-based protein production. Spring rapeseed, both turnip rape (Brassica rapa L.) and oilseed rape (Brassica napus L.), are adapted to such northern conditions. This study examines the potential for genotype and environment induced trade-off between oil and protein in rapeseed in order to enhance further the status of rapeseed as a protein crop for northern areas. Datasets on advanced breeding progenies (including cultivars) were provided by Boreal Plant Breeding Ltd., while environment-induced variability in combinations of protein and oil content was studied by using long-term, multi-location datasets of MTT Official Variety Trials. Oilseed rape has more potential as a protein producer than turnip rape, with some 100 kg/ha difference in protein yields. Selecting lines superior in seed protein content at the expense of oil was not a potential means to consolidate protein production capacity per hectare: seed and protein yields were higher the better the capacity of the line to store oil. This can only mean that obviously the lower energy demand for oil synthesis was not alternatively used to boost protein production, but actually vice versa. In the case of environment-induced variation, the highest protein yields were produced in experiments where relatively high protein content was associated with modest oil content, but such conditions were characterised as inefficient in general production capacity and thereby, excessive in applied nitrogen fertiliser. Hence, we were not able to identify promising opportunities for prompt and energy-efficient trade-off between protein and oil in rapeseed.     

Biplot Analysis of Genotype by Environment for Cooking Quality in Hybrid Rice: A Tool for Line × Tester Data

A study of combining ability for improving rice cooking quality was carried out via genotype plus genotype × environment(GGE) biplot. Four restorer lines and three male sterile lines were used to obtain F1 in a line × tester trial at the Rice Research Institute, Amol, Iran in 2009. GGE biplot analysis showed that Neda and IR56 were the best general combiners for amylose content(AC), whereas Nemat and IR28 had the highest general combining ability(GCA) effects for gelatinization temperature(GT), and IR58 and IR59 showed the highest GCA effects in terms of gel consistency(GC). Meanwhile, IR58 and IR59 showed large specific combining ability(SCA) effects for AC, while Neda and SA13 had high SCA effects for GT. Nemat and IR28 had large SCA effects for GC. Because intermediate levels of AC, GT and GC are ideal, Nemat × IR59 was considered as the best possible cross. Based on these results, the GGE biplot showed good potential for identifying suitable parents, heterotic crosses and the best hybrids in line × tester data.     

Is Partial Root-Zone Drying More Appropriate than Drip Irrigation to Save Water in China? A Preliminary Comparative Analysis for Potato Cultivation

China is the largest worldwide potato producer where around half of the crops is planted in the semi-arid region frequently affected by water restriction. While innovative methods are needed for water-saving irrigation methods, the use of low-cost and environmental-friendly technology must be prioritised. In this study, potato production under drip irrigation (DI, commonly adopted to save water) was compared with partial root-zone drying furrow irrigation (PRD) using the same water volume per irrigation, in both methods. Two initiation timings (early and late) were tested under shelter and field conditions, the water supplied during every irrigation being 50% of the crop water demand calculated for furrow full irrigation (FI, as control). The comparison of both methods was done through the assessment of tuber fresh-yield and estimated economic and environmental (carbon footprint and irrigation water use efficiency, WUE_i) benefits. Late PRD and DI produced the highest WUE_i without significant yield reduction. PRD produced 3.1% higher net benefit than DI with an estimated CO₂ emission of 3659 kg ha^?1 CO₂ (14% lower than DI). The input-output ratio (total input costs/yield output) for PRD was 0.4, which was 10% lower than DI. The study’s results suggested that PRD, with no less than 50% of the water applied in FI per application, not only maintained yield but could also increase revenues while saving water and reducing CO₂ emissions, compared to DI. Such results might help reduce the pressure on the water reserves in semi-arid potato-producing areas in China. Notwithstanding, a scaling-up of PRD technology must be tested in those regions to substantiate the findings of this preliminary study.