Herbicide resistance evolution, fitness cost, and the fear of the superweeds.

Despite considerable differences in cropping systems around the globe, chemical weed control is a key tool in conventional agroecosystems, which has led to an increase in herbicide resistance. Although mutations causing resistance are thought to have an adaptation cost in resistant plants compared to the susceptible ones under herbicide-free conditions, such cost may not always express or will express under certain ecological conditions. To ensure that herbicides will keep going as viable instruments in agricultural production, strategies to minimize resistance are needed. Proactive or reactive strategies for weed control should utilize an overall integrated weed management approach by combining as many weed management practices as possible. The term 'superweed' was used initially to describe the phenomenon in which genetically engineered crops would become troublesome weeds and that the genes of interest would spread into related weeds, rendering them problematic, or into wild species, turning them into troublesome weeds. Contrary to the above definition, the use of this term in the literature has often been linked with herbicide resistance, mostly related to the cultivation of genetically engineered crops and the related increase in the use of glyphosate, which rapidly selected resistant weed populations. From a scientific point of view, weeds are better survivors than non-weedy species and cause crop problems because they have several unique traits, e.g., they are aggressive, adapt easily to different environments, produce many seeds, compete strongly with crops, disperse easily, are difficult to control, traits which occur whether weeds are herbicide-resistant or not. We propose that the term 'superweed' should be referred to weeds with resistant populations to several herbicides with diverse modes of action (MOAs).

Safety behavior in pesticide use among farmers of northern Greece: the role of information sources.

BACKGROUND: Farmers' compliance with common safety practices in pesticide use (i.e., keeping records of pesticide applications, reading the information of pesticide labels, and taking protective measures during pesticide handling) and the use of information sources about pesticides were studied in a simple random sample of farmers in Evros Province, northern Greece. RESULTS: According to the three common safety practices considered in the study, most farmers (56.9%) complied with safety practices. Nevertheless, a noticeable proportion of the farmers never kept records of pesticide applications (33.9%), never read the information of pesticide labels (20.2%), and never took protective measures during pesticide handling (24.8%). Farmers reported using up to six different sources of information about pesticides, but the majority (51.4%) reported using up to one source and almost one-third (33.9%) relied on own sources. The most common information source about pesticides was the staff of the agricultural supply stores, used by 88.1% of the farmers. Safety behavior was positively correlated with total sources of information (P < 0.01) and information by the agricultural supply stores (P < 0.01). Multiple regression analysis showed that safety behavior was reduced in females, whereas it was increased in farmers with high education, high number of plots, and high level of information sources. CONCLUSION: Despite good levels of safety behavior by most farmers, keeping records of sprayings should be improved. Using multiple information sources about pesticides is crucial to improve safety behavior of farmers. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Elucidating molecular characterization of chlorpyrifos and profenofos degrading distinct bacterial strains for enhancing seed germination potential of Gossypium arboreum L.

Chlorpyrifos (CP) and profenofos (PF) are organophosphate pesticides (OPs) widely used in agriculture and are noxious to both fauna and flora. The presented work was designed to attenuate the toxicity of both pesticides in the growth parameters of a cotton crop by applying plant growth-promoting rhizobacteria (PGPR), namely Pseudomonas aeruginosa PM36 and Bacillus sp. PM37. The multifarious biological activities of both strains include plant growth-promoting traits, including phosphate solubilization; indole-3-acetic acid (IAA), siderophore, and HCN production; nitrogen fixation; and enzymatic activity such as cellulase, protease, amylase, and catalase. Furthermore, the molecular profiling of multi-stress-responsive genes, including acdS, ituC, czcD, nifH, and sfp, also confirmed the plant growth regulation and abiotic stress tolerance potential of PM36 and PM37. Both strains (PM36 and PM37) revealed 92% and 89% of CP degradation at 50 ppm and 87% and 81% at 150 ppm within 7 days. Simultaneously 94% and 98% PF degradation was observed at 50 ppm and 90% and 92% at 150 ppm within 7 days at 35 °C and pH 7. Biodegradation was analyzed using HPLC and FTIR. The strains exhibited first-order reaction kinetics, indicating their reliance on CP and PF as energy and carbon sources. The presence of opd, mpd, and opdA genes in both strains also supported the CP and PF degradation potential of both strains. Inoculation of strains under normal and OP stress conditions resulted in a significant increase in seed germination, plant biomass, and chlorophyll contents of the cotton seedling. Our findings indicate that the strains PM36 and PM37 have abilities as biodegraders and plant growth promoters, with potential applications in crop sciences and bioremediation studies. These strains could serve as an environmentally friendly, sustainable, and socially acceptable solution to manage OP-contaminated sites.

Herbicide use in conventional cereal production in northern Greece: An appraisal through the theory of planned behavior.

BACKGROUND: Herbicides are the major method of weed control in most conventional cropping systems, but what affects farmers' intention to use herbicides has not been studied extensively. This study examined herbicide use among cereal farmers of northern Greece and tested for the first time whether the theory of planned behavior (TPB) can explain farmers' behavior in the adoption of herbicide use. RESULTS: Most farmers showed favorable attitudes towards herbicide use (71.2%), high levels of perceived behavioral control (PBC) of herbicide use (62.4%), and positive intention to use herbicides (67.6%). By contrast, most farmers (60.4%) were negative in following the advice of others in the adoption of herbicides. Finally, most farmers (82.8%) used herbicides in cereal production. The TPB explained 47.6% of the variation in farmers' intention to use herbicides. Logistic regression showed that intention and PBC positively affected (P < 0.01) farmers' behavior in herbicide use, explaining 45.8-76.2% of the variation in farmers' behavior. Path analysis showed that attitudes, subjective norms, and PBC had a direct impact on intention. Gender had an indirect impact on intention through PBC, while age and farming as a main profession had an indirect impact on intention through attitudes and subjective norms. Furthermore, education had an indirect impact on intention through attitudes and PBC. CONCLUSION: Farmers' intentions and behavior in the use of herbicides in cereal production could be explained by the TPB. Attitudes showed the strongest total effect on the intention to use herbicides. © 2022 Society of Chemical Industry.

Microbial detoxification of dimethoate through mediated hydrolysis by Brucella sp. PS4: molecular profiling and plant growth-promoting traits.

High toxicity of dimethoate requires efficient ways for detoxification and removal of its residues in contaminated environments. Microbial remediation is a process that utilizes the degradation potential of microbes to provide a cost-effective and reliable approach for pesticide abatement. For this purpose, a dimethoate-degrading bacterium Brucella sp. was isolated from a contaminated agricultural soil sample in Multan, Pakistan. This isolate was found to tolerate up to 100 ppm of dimethoate in minimal salt medium and was further evaluated for plant growth-promoting traits. The strain gave positive results for amylase, ammonia, and catalase production, while other traits such as indole acetic acid production and potassium solubilization were also confirmed. Thus, the strain could play an important role for plant nutrient transmission in the plant rhizosphere. Optimization of growth parameters (i.e., pH and temperature) depicted the potential of PS4 to be best tolerating dimethoate, with maximum cell density at λ 600 nm. Optimum pH and temperature for growth were found to be 6 and 35 °C, respectively. Based on optimization results as well as different attributes, the rhizospheric bacterial isolate PS4 was further subjected to a batch degradation experiment under different concentrations of dimethoate (25, 50, 75, and 100 ppm). This promising dimethoate-degrading isolate was found to degrade 83% of dimethoate (at 100 ppm) within a period of 7 days. In addition, it degraded 88% of dimethoate at 50 ppm, indicating that the bacterial isolate utilized dimethoate solely as a source of energy. The strain followed the first order reaction kinetics, depicting its dependence on dimethoate as energy and carbon source. Molecular profiling further supported its role in plant growth promotion and multi-stress tolerance. This research showed that Brucella sp. is capable of degrading dimethoate, and therefore, it would be useful in the investigation of novel bioremediation techniques at pesticide-polluted sites.

Modeling farmers' intention for safe pesticide use: the role of risk perception and use of information sources.

Intention for safe pesticide use plays a crucial role in the mode of pesticide spraying, but several factors are involved in the formation of intention by farmers. This work focused on the levels of farmers' perception of pesticide risks (i.e., toxicity levels, health, and environmental effects) and utilization of information sources and examined their impact on intention for safe pesticide use in rural Iran. Most farmers (53%) showed low levels of risk perception by pesticide use and reported poor use of the available information sources about pesticides. Pesticide retailers were mentioned as the primary information point of farmers. In addition, almost half of the farmers (49.2%) expressed worryingly negative intention for safe pesticide use. Perception of pesticide risks and utilization of information sources were significantly correlated with age and spraying experience (P < 0.01), while intention for safe pesticide use was significantly correlated with farming experience (P < 0.05) and spraying experience (P < 0.05). Analysis with structural equation modeling showed that perception of pesticide risks and use of information sources together explained 80% of the variability in farmers' intention. Moreover, perception of pesticide risks (P < 0.01) and employment of information sources (P < 0.05) had a positive relationship with intention for safe handling of pesticides, thus showing a predictive link with intention. Therefore, promoting farmers' perception of pesticide risks and providing credible information sources are essential for improving intention for safe pesticide use among farmers.

Horticultural products irrigated with treated sewage: are they acceptable?

Public acceptance of treated sewage (TS) reuse in agriculture is a key element in successful implementation of TS reuse projects, but relevant research on the topic is limited. This study examined public willingness to accept (WTA) and willingness to pay (WTP) for agricultural products derived by irrigation with TS in Lorestan province, Iran, applying the contingent valuation (CV) method. The agricultural products determined for the study included corn, peaches, apricots, and plums, while TS was introduced in three qualities [Q1, complete TS treatment (i.e., physical treatment, aeration, and chemical treatment); Q2, partial TS treatment (i.e., physical treatment and aeration); and Q3, no TS treatment]. With reference to WTA, products irrigated with Q1 TS received 62.7% positive responses, while products irrigated with Q2 TS and Q3 TS received 21.3% and 17.0% positive responses, respectively. With reference to WTP, data showed that if the price of products derived by irrigation with TS was less than that of products irrigated with fresh water, some people would be willing to pay for these products (52.0% positive responses versus 48.0% negative responses). Awareness had a significantly positive impact on WTA1 and WTA2 (products irrigated with Q1 TS and Q2 TS, respectively) as well as on WTP1, WTP2, and WTP3 (products irrigated with Q1 TS, Q2 TS, and Q3 TS, respectively). Similarly, information sources had a significantly positive effect on WTP1, WTP2, and WTP3. Overall, individuals with high levels of health risk perception and high awareness showed high WTA, while non-processed corn and men were associated with low WTA. Concerning WTP, individuals with high awareness and those who had access to information sources showed high WTP, while men were associated with low WTP. Information about the importance of TS reuse, reduction of prices of products derived by irrigation with TS, and promotion of public confidence in TS are essential to increase public WTA and WTP.

Farmers' intention to reduce pesticide use: the role of perceived risk of loss in the model of the planned behavior theory.

Numerous studies have examined how farmers are involved and behave in the use of pesticides, but what drives farmers' intention to diminish pesticide applications is mostly unknown. This study explored farmers' intention to minimize pesticide use, through the theory of planned behavior (TPB) and an adjusted form of the TPB, with perceived risk of loss as an additional variable to the original model. On a scale from 1 to 5, intention to reduce pesticide use had the lowest score of all variables (2.36), indicating that most farmers did not show intention to reduce pesticide use. Only 15.2% of the farmers were willing to reduce pesticide use, while 8.3% were undecided. Moreover, 58.2% of the farmers had high levels of perceived risk of loss by the reduction of pesticide use, which explained 37.3% of farmers' intention. From the three variables of the TPB, attitudes had the highest score (3.34), indicating slightly favorable attitudes toward pesticide reduction, while perceived behavior control had the lowest score (2.70), indicating poor control of pesticide reduction. Also, the three basic variables of the TPB were positively correlated (P < 0.01) with farmers' intention to reduce pesticides, while a negative correlation (P < 0.01) was noted between intention to reduce pesticides and perceived risk of loss. The three basic variables of the TPB were significant predictors of intention, capturing 54.7% of the variation in farmers' intention. Adding perceived risk of loss as a construct to the TPB improved the predictive ability of the original model. Poor control of pesticide reduction (high-perceived barriers) and high perceived risk of loss drive farmers' intention to reduce the use of pesticides. Advancing alternative crop protection methods focusing on agro-ecology and integrated pest management should be included in the work of extension services.

Farmers' behavior in reading and using risk information displayed on pesticide labels: a test with the theory of planned behavior.

BACKGROUND: Labels are the first source of information for the safe use of pesticides, but farmers rarely read labels before pesticide use. Using data from a sample of 300 orchard farmers in Meshginshar County, Iran, this study examined farmers' intention and behavior in reading and using risk information displayed on pesticide labels, using the theory of planned behavior (TPB). RESULTS: Only 26% of the respondents mentioned that they read pesticide labels. Most farmers showed a low tendency towards reading pesticide labels due to low education, advanced age, and label-related problems, i.e., use of too technical language and unclear texts with small and illegible fonts. From the three basic variables of the TPB, subjective norms and perceived behavioral control (PBC) showed a significant impact on intention, while attitudes showed no significant impact. The three main variables of the TPB explained 90.2% of the variance in farmers' intention to read and use the labels. Furthermore, PBC and intention significantly affected farmers' actual behavior in reading and using the labels, explaining 78.5% of the variance in farmers' actual behavior. Age, experience in farming, and experience in spraying were negatively correlated with all variables of the TPB. CONCLUSION: Findings provide new insights into farmers' behavior in reading pesticide labels by using for the first time the TPB. Pesticide manufacturers should consider the special conditions of subsistence farmers (low education and advanced age) when preparing pesticide labels and the extension services could use those findings to improve farmers' training in the use of pesticide labels. © 2021 Society of Chemical Industry.

Farmers' behavior towards safe pesticide handling: An analysis with the theory of planned behavior.

Inappropriate handling of pesticides in agriculture poses a major risk to the environment and human health, but factors affecting farmers' behavior are diverse and often unclear. The present study examined farmers' behavior in safe pesticide use (disposal of spray solution leftovers, places for washing sprayers, disposal of rinsates, and use of personal protective equipment) in Ardabil Province, Iran by applying the well-known theory of planned behavior, which states that attitudes, subjective norms, and perceived behavioral control of individuals shape intention and engagement in a specific behavior. Almost 30% of the farmers threw pesticide spray solution leftovers away, while the remaining farmers kept it for next spraying. Concerning place for washing sprayers, 55.3% of the farmers washed sprayers in their home yard, 21.0% washed them in the river or the canal flow, and 14.7% washed them in the water source of the farm. Just less than two-thirds (64.3%) of the farmers said that they leave the rinsates onto the farm, while almost one-third (34.0%) said that they pour the rinsates into the river or the canal flow. Most farmers used trousers and blouse and to a lesser extent mask, gloves, and hat when handling pesticides. Attitudes towards safe pesticide use showed the highest mean score (2.91), illustrating neutral to relatively negative attitudes of farmers towards safe pesticide use. Intention showed the lowest mean score (2.28), indicating poor motive to use pesticides safely. Attitudes showed positive impact, while perceived behavioral control showed negative impact on intention. Subjective norms had no significant impact on intention. These three constructs totally explained 78.1% of the variance in farmers' intention towards safe pesticide use. Improving attitudes and perceived behavioral control of farmers towards safe pesticide use through extension education should be targeted for improving farmers' intention and behavior towards safe pesticide handling.

Modeling farmers' intention to use pesticides: An expanded version of the theory of planned behavior.

Numerous studies have been carried out on pesticide handling practices in agriculture, but drivers of farmers' intentions to use pesticides are not well documented. The main purpose of this study was to explore farmers' intention to use pesticides in agriculture, based on an expanded version of the theory of planned behavior (TPB), with knowledge about pesticides and moral norms as additional constructs in the original TPB model. A sample of 400 cereal farmers of irrigated farmlands of Moghan plain, Iran was selected using multistage cluster sampling. Knowledge about pesticides hazards was the most important variable affecting farmers' intention to use pesticides. Knowledge mainly impacted perceived behavioral control of pesticide use and attitude towards pesticides. Thus, high levels of knowledge about pesticides were linked with greater influence of attitudes towards pesticides on farmers' intention. In turn, perceived behavioral control of pesticide use was affected by moral norms, subjective norms, and attitudes towards pesticide use. Moral norms and subjective norms also affected attitudes towards pesticides. Findings offer new evidence on the interrelationship of several variables in forming farmers' intention to use pesticides in the context of the widely used model of the TPB, for which no data are available in the literature. Promoting knowledge about pesticides is a fundamental step for regulating pesticide use among farmers, probably by stabilizing and rendering farmers' attitudes resistant to change. Moral norms and subjective norms can play a role mainly by affecting perceived behavioral control and attitudes towards pesticides. Combination of educational interventions for upgrading general knowledge about pesticides, with training courses, disincentives, and public awareness campaigns relating to pesticides may improve our ability to affect farmers' behavior.

Cadmium accumulation, translocation factor, and health risk potential in a wastewater-irrigated soil-wheat (Triticum aestivum L.) system.

The accumulation of trace elements in wastewater-irrigated soils may introduce them to the food chain and therefore can threaten human health. The present study investigated the accumulation, translocation factor, and health risk potential of cadmium (Cd) in a soil-wheat system irrigated with treated wastewater compared with a reference soil (irrigated with fresh water). All treated wastewater-irrigated soils showed significantly higher levels of electrical conductivity (EC) than that of reference soil by 75-143%. Irrigation with treated wastewater increased both available and total Cd content in soil by 2-4 times. In all irrigated sites, Cd content was about twice as great as the maximum acceptable rate. Bioconcentration factor (BCF) and translocation factor (TF) indicated that Cd was mainly accumulated in the roots (BCF = 2.2-3.1), while little mobilization from roots to stems and grains was noted (TFshoot/root = 0.07-0.21; TFgrain/root = 0.18-0.24). The average hazard quotient (HQ) for different age groups of the population varied in the range of 0.1-1.0, implying low non-carcinogenic health risk of Cd to local wheat-consuming residents. The risk of Cd to cause carcinogenic health risk (CR) was in the range of 1 × 10-5 to 1 × 10-4, indicating low to moderate potential risk. CR for different age groups was in the order: individuals above 18 years old > individuals 7-18 years old > individuals 0-6 years old. For reducing potential health risks to local people, it is imperative to continuously monitor heavy metal levels in the wheat-soil system and urgently adopt more efficient managerial strategies to reduce Cd contamination.

Health problems from pesticide exposure and personal protective measures among women cotton workers in southern Pakistan.

Women are the main cotton pickers in Pakistan even from their childhood, but due to unawareness of pesticide risks and poor knowledge of personal protection opportunities, they typically do not use personal protective measures. Albeit a major agricultural topic in Pakistan, relevant research is limited. The present study illustrates health problems from pesticide exposure during cotton harvest and the use of personal protective measures among 260 female cotton-picking workers from Shaheed Benazirabad District of Sindh Province in southern Pakistan. Skin injury, eye injury, headache, stomachache, and fever were the main health problems due to pesticide exposure according to workers' experience. Medical treatment costs of health problems were more than double (2.48 times higher) than preventive measures costs. More than half of the cotton workers surveyed did not use any protective measure during cotton picking, while 22.3% used a muffler/scarf/cloth for covering their face and 10.8% used gloves. Covering face with muffler/scarf/cloth was higher in young (P < 0.05), married (P < 0.05), and high experienced workers (P < 0.05), while no significant trends were found in the use of gloves. The use of protective measures was positively correlated with education and some experience in cotton picking. Binary logit regression showed that advanced age and high picking experience were positively associated with the use of personal protective measures, while illiteracy, traditional treatment, and medical treatment in case of illness were negatively associated with the use of personal protective measures. Findings shed new light on the topic of personal safety among women cotton pickers in Pakistan. Increasing formal education and implementing training programs for personal protective measures are important to reduce health risk and health cost by pesticides among women workers.