Volunteer Plants Research Articles

Long‐term trends in the genotypic integrity, phenotype and reproductive development of perennial ryegrass (Lolium perenne L.) populations in New Zealand dairy pastures: Implications for pasture persistence

AbstractFailure of perennial ryegrass‐based pastures to persist beyond 3 years post‐sowing is an increasing threat to the sustainability of livestock industries in the north of New Zealand. Little is known of the long‐term responses of plants and populations to the environmental stresses responsible for persistence failure, or the effects of ryegrass genetics on those responses. Plants were collected from 10‐year‐old pastures sown in two environments (Waikato, North Island: warm‐temperate, summer/autumn dry; Canterbury, South Island: cool temperate, irrigated) to four ryegrass functional types and grazed by dairy cattle. Surviving plants in Canterbury pastures were almost all true‐to‐type for the original genotype, whereas there was substantial ingress of volunteer plants in the diploid cultivars in Waikato. Plants confirmed as true‐to‐type were compared to reference plants grown from the original seed lines. Leaf mass was lower in survivor plants than in reference plants for all functional types. This effect was reversed by recruitment of new plants from seed in a grazing deferment treatment applied at the Waikato site 18 months before plant collection, in a manner consistent with epigenetic control. Reproductive development was delayed by 4–6 days in survivors of mid‐ and late flowering diploid cultivars: this effect appeared to be the result of true genetic differentiation. There was less aftermath heading in the Canterbury survivors, but not Waikato survivors, compared with the reference plants. The relevance of these findings for ryegrass survival strategies and targeted selection of traits for improved persistence is discussed.

Behavior and damage potential of the newly emerged pest Myochrous armatus (Chrysomelidae: Eumolpinae) on soybean plants in Brazil

AbstractMyochrous armatus Baly, 1865 (Coleoptera: Chrysomelidae) has expanded its occurrence significantly into soybean‐growing areas of Brazilian Cerrado and became an important early‐season soil pest. Experiments were performed under field conditions from 2020 to 2023 to assess several aspects: (1) population behaviour over crop season and offseason; (2) day/night behaviour during the early stages of soybean plants and (3) injury to plants and potential damage to soybean yield to establish the Economic Injury Level (EIL). Adults of the M. armatus population presented a season‐long abundance during the specific period from late October to January, with major captures in November and December (end of Spring), either inside or on the edge of soybean fields. Weeds and volunteer plants of corn and cotton hosts adults and eggs. These findings suggest an univoltine life cycle. Behavioural assessments revealed that M. armatus does not exhibit a specific day, night or crepuscular behaviour, performing deeds at any time. The majority of insects (40% to 70%) were found in the soil throughout the day and night. Adults feed on soybean plants by scraping or cutting the stem, cotyledon, petiole and apical sprouting. Their preference is initially for the stem and cotyledon (up to 14 days after emergence), and later for the petiole (after 21 days of emergence). After 7 days of coexistence at V1‐V3 soybean stages, we observed a potential yield reduction of 35% for each insect per plant. Dynamic EIL estimations are between 0.4 and 1.9 adults per row metre, depending on the grower productivity expectation, control costs and soybean market value. Our results are fundamental for establishing Integrated Pest Management for M. armatus in soybean and other crop systems.

Effectiveness of herbicides against the volunteer plants of imidazolinone-resistant sunflower in oil flax sowings

In 2020-2021, we conducted research on the effect of herbicides on oil flax productivity and volunteer plants of imidazolinone-resistant sunflower in oil flax sowings. We used the contact herbicide Basagran, AS (a.i. bentazon, 480 g/l) and the systemic herbicides Tifi, WDG (a.i. thifensulfuron-methyl, 750 g/kg), Cleo, WDG (a.i. clopyralid, 750 g/kg), Magnum, WDG (a.i. metsulfuron-methyl, 600 g/kg), Zellek-super, EC (a.i. haloxyfop-P-methyl,104 g/l), Miura, EC (a.i. quizalofop-P-ethyl,125 g/l), Sekator Turbo, OD (a.i. amidosulfuron, 100 g/l + iodosulfuron-methyl-sodium, 25 g/l + mefenpyr-diethyl, 250 g/l). We evaluated the phytotoxicity of the herbicides on the volunteer plants using a 9-point EWRC scale. We found that the of Basagran, AS (4.0 l/ha) + Zellek-super, EC (1.0 l/ha) + Cleo, WDG (0.12 kg/ha) provides the effective control of the volunteer plants and contributes to the stable high indicators of oil flax productivity.

Volunteer rapeseed infestation and management in corn

AbstractThe study was conducted to evaluate the effect of different termination timings for rapeseed (Brassica napus L.) cover crop on biomass production, termination efficiency, and volunteer infestation in the successive cash crop (corn, Zea mays), and control of volunteer rapeseed with herbicides. Delaying termination from 28 days before planting corn (DBP) to 14, 5, or 1 DBP, increased rapeseed biomass by 85%, 148%, and 158%, respectively. Rapeseed termination efficiency was greatest 28 DBP (99%) followed by 14 DBP (92%) and 5 DBP (89%) with the combined use of a roller‐crimper and 2,4‐D [2,4‐dichlorophenoxy acetic acid] + glufosinate [2‐amino‐4‐(hydroxymethylphosphinyl) butanoic acid]. The sole use of roller‐crimper 1 DBP provided only 56% termination efficiency. Zero volunteer plants were observed in successive cash crops with the 28 DBP termination treatment; however, at 14, 5, and 1 DBP termination, the number of volunteer rapeseed plants m−2 were 5, 12, and 22, respectively. Regression analysis showed that variation in volunteer rapeseed density can be explained better by termination efficiency (R2 = 0.80) as compared to rapeseed biomass at termination (R2 = 0.46). Among pre‐emergence (PRE) herbicides, mesotrione [2‐(4‐mesyl‐2‐nitrobenzoyl)‐3‐hydroxycylohex‐2‐enone], rimsulfuron [N‐[[(4,6‐dimethoxy‐2‐pyrimidinyl)amino]carbonyl]‐3‐(ethylsulfonyl)‐2‐pyridinesulfonamide], and flumioxazin {2‐[7‐fluoro‐3,4‐dihydro‐3‐oxo‐4‐(2‐propynyl)‐2H‐1,4‐benzoxazin‐6‐yl]‐4,5,6,7‐tetrahydro‐1H‐isoindole‐1,3(2H)‐dione} provided more than 95% volunteer rapeseed control, and 92%–94% control with PRE‐application of atrazine [6‐chloro‐N‐ethyl‐N9‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], isoxaflutole [(5‐cyclopropyl‐4‐isoxazolyl)[2‐(methylsulfonyl)‐4‐(trifluoromethyl)‐phenyl]methanone], metribuzin [4‐amino‐6‐(1,1‐dimethylethyl)‐3‐(methylthio)‐1,2,4‐triazin‐5(4H)‐one], and pyroxasulfone [3‐[[[5‐(difluoromethoxy)‐1‐methyl‐3‐(trifluoromethyl)‐1H‐pyrazol‐4‐yl]methyl]sulfonyl]‐4,5‐dihydro‐5,5‐dimethylisoxazole]. Among post‐emergence (POST) herbicides, atrazine and glyphosate [N‐(phosphonomethyl) glycine] provided 99% control of rapeseed followed by glufosinate (89%). Results indicate that ineffective or delayed termination of rapeseed can result in volunteer infestation in successive crops, which can be controlled by tested PRE and POST herbicides at an early stage.

Volunteer Plants' Occurrence and the Environmental Adaptability of Genetically Modified Fodder Corn upon Unintentional Release into the Environment.

The number of corn cultivars that have been improved using genetically modified technology continues to increase. However, concerns about the unintentional release of living-modified organisms (LMOs) into the environment still exist. Specifically, there are cases where LMO crops grown as fodder are released into the environment and form a volunteer plant community, which raises concerns about their safety. In this study, we analyzed the possibility of weediness and volunteer plants' occurrence when GMO fodder corn grains distributed in Korea are unintentionally released into the environment. Volunteer plants' occurrence was investigated by directly sowing grains in an untreated field. The results showed that the germination rate was extremely low, and even if a corn seed germinated, it could not grow into an adult plant and would die due to weed competition. In addition, the germination rate of edible and fodder grains was affected by temperature (it was high at 20 °C and 30 °C but low at 40 °C and extremely low at 10 °C), and it was higher in the former than in the latter. And the germination rate was higher in Daehakchal (edible corn grains) than in Gwangpyeongok (fodder corn grains). The environmental risk assessment data obtained in this study can be used for future evaluations of the weediness potential of crops and the development of volunteer plant suppression technology in response to unintentional GMO release.

Distribution and Incidence of Watermelon Crinkle Leaf-Associated Virus 1, Watermelon Crinkle Leaf-Associated Virus 2, and Other Viruses in Cucurbits in South Florida

A survey of cucurbits grown in South Florida was conducted from 2020 to 2022 for viruses. A total of 481 plant samples (470 cucurbit and 11 noncucurbit) included watermelon, squash, cantaloupe, cucumber, zucchini, five weeds commonly found in cucurbit fields, and two vegetable volunteer plants growing in a watermelon field. Samples were tested for cucurbit chlorotic yellows virus, squash vein yellowing virus, papaya ringspot virus-W, watermelon crinkle leaf-associated virus 1 (WCLaV-1), watermelon crinkle leaf-associated virus 2 (WCLaV-2), cucurbit yellow stunting disorder virus (CYSDV), and cucurbit leaf crumple virus. All seven viruses were detected with WCLaV-1 as the predominant virus found in cucurbits, followed by CYSDV and WCLaV-2. The majority of samples were mixed infections containing two or more viruses. Host tissue testing found the peduncle was a good source for testing for all viruses. Host symptoms were variable on leaves for WCLaV-1 and WCLaV-2 and in mixed infections with the other five viruses. More studies are required to ascertain the role of WCLaV-1 and WCLaV-2 in mixed infections and their effects on plant health, fruit quality, and yield.

Борьба с засорителем посевов масличного льна – имидазолиноноустойчивым подсолнечником

The research was conducted in 2020-2022 to find effective ways of controlling the volunteer plants of imidazolinone-resistant sunflower in oil flax sowings, providing high biological and economic efficiency, crop yield, and seed quality on leached chernozem in natural and climatic conditions of the Western Ciscaucasia. We studied methods of chemical protection of oil flax with tank mixtures of herbicide combinations: anticotyledonous contact herbicide Basagran, WS and systemic herbicide Cleo, WDG, Sekator Turbo, OD, and graminicide Zellek-super, EC. We used established methods for field agronomic experiments with oil crops. Seeds of imidazolinone-resistant sunflower hybrid were evenly sown on the experimental plot to simulate the volunteer plants. The phytotoxicity of herbicides on sunflower plants was evaluated using a 9-point EWRC scale. The tank mixtures Basagran,WS (4 l/ha) + Zellek-super, EC (1.0 l/ha) and Basagran, WS (4 l/ha) + Sekator Turbo, OD (0.1 l/ha) + Zellek-super, EC (1.0 l/ha) do not provide ef-fective control of the volunteer plants and are not recommended for use. The composition Basagran, WS (4 l/ha) + Cleo, WDG (0.12 kg/ha) + Zellek-super, EC (1.0 l/ha) provides destruction of the volunteer plants, contributing to higher yield and oil content of seeds, but it is very expensive and decreases the laboratory germinating ability of flax seeds, so it cannot be used in industrial seed production. A tank mixture of Cleo, WDG (0.12 kg/ha) + Sekator Turbo, OD (0.1 l/ha) + Zellek-super, EC (1.0 l/ha) has lower cost, provides high herbicidal effectiveness against the volunteer plants of imidazolinone-resistant sunflower, contributes to obtaining a high yield, oil content and laboratory germination of oil flax seeds and is recommended for use both in industrial seed production and in the production of commercial seeds.

INTERFERENCE AND ECONOMIC THRESHOLD LEVEL OF TRANSGENIC VOLUNTEER SOYBEAN PLANTS IN MAIZE CROP

The interference caused by volunteer plants dispersed after harvest can cause economic losses to growers. This work aims to identify the competitive ability and the economic threshold level of maize hybrids in different densities of volunteer soybean. The experiment was carried out in the field, in a randomized blocks design, with one replication. The treatments were maize hybrids (NK 422 Vip3; NK 488 Vip3; Syn Supremo Vip3; Brevant 2A401 PWU; FS 481 PW; e FS 620 PWU) and 12 densities of volunteer soybean established for each hybrid, going from 0 to maximum of 130 plants m-2. At 30 days after emergence, were assessed the plant density (PD), soil cover (SC), leaf area (LA), and shot dry mass (SDM) of volunteer soybean plants. The maize hybrids NK 488 Vip3, Syn Supremo Vip3, and Brevant 2A401 PWU showed the highest competitive abilities that influenced economic threshold levels that ranged from 1,01 to 3,82 plants m-2. Thus, it concluded that volunteer soybean causes yield losses when infesting maize, and hybrids show different competitive abilities, being the economic threshold level directly influenced by these characteristics.

Pre-emergence control and interference of voluntary maize plants on a soybean crop in Brazilian Cerrado

The succession of soybean/maize has been largely adopted. Storm damage and crop problems can lead to grain loss, generating maize ear fragments or even whole ears that remain in the soil and still display germination viability, resulting in the occurrence of volunteer plants. In this context, the present study aimed to evaluate the interference of voluntary maize plants on soybean and investigate the susceptibility of maize hybrids to pre-emergence herbicides. In the first step, an experiment was performed evaluating the influence of voluntary maize plant density and spatial distribution on soybean. The experiment was performed in a randomized completely block design (RCBD) with four replications, with treatments disposed in factorial arrangement (2 x 4) + 1. The first factor corresponded to the spatial distribution of maize plants: row or in between soybean rows; while the second factor adopted four infestation densities of maize plants m-2: 4, 8, 12, and 16. The additional treatment consisted of a control without maize plants. For the second step, an experiment was conducted in two locations aiming to determine the efficacy of pre-emergence herbicides in the control of voluntary maize. Both experiments were installed in RCBD in a split-plot scheme with four replications. Fomesafen, lactofen, sulfentrazone, chlorimuron-ethyl, diclosulam, flumetsulam, imazethapyr, clomazone, metribuzin, [sulfentrazone + diuron], [imazethapyr + flumioxazin], and a control without herbicide application were evaluated in the main plot. In each subplot, the maize hybrids DKB310 PRO3™ and DKB390 PRO3™ were evaluated. No influence on the position of voluntary maize on the soybean yield was observed. The presence of the maize population led to a progressive decrease in soybean yield, ranging up to 86%, at 16 plants m-2. DKB390 displayed a stand reduction of 82.88% after the use of diclosulam. Diclosulam led to better results regarding maize plant decreases for both hybrids.

Available Strategies for the Management of Andean Lupin Anthracnose.

The lupin (Lupinus mutabilis Sweet) is a legume domesticated and cultivated for more than 4000 years by the pre-Hispanic cultures of the Andean zone. Due to its good taste and protein content, the lupin seed contributes significantly to the food and nutritional security of the Andean population. However, lupin is susceptible to diseases, and of these, anthracnose is the most devastating as it affects the whole crop, including leaves, stems, pods, and seeds. This review focuses on available strategies for management of lupin anthracnose from sowing to harvest. Seed disinfection is the primary anthracnose management strategy. Seed treatment with fungicides reduces transmission from seed to seedling, but it does not eradicate anthracnose. Attention is given to alternative strategies to limit this seed-borne pathogen as well as to enhance plant resistance and to promote plant growth. For anthracnose management in the field, integrated practices are discussed that encompass control of volunteer plants, lupin ontogenetic resistance, and rotation of biocontrol with chemical fungicides at susceptible phenological stages. This review covers some local experiences on various aspects of anthracnose management that could prove useful to other the groups focusing on the problem.

Sustainable and efficient control of sunflower downy mildew by means of genetic resistance: a review.

The breeding of sunflower (Helianthus annuus L.) for resistance to downy mildew (caused by the oomycete Plasmopara halstedii Farl. Berl. & de Toni) is reviewed in this work under the scope of its sustainability and efficiency. When sunflower turned into an oilseed crop, resistance to the disease was included in its initial breeding strategies. Subsequent development of genomic tools allowed a significant expansion of the knowledge on the diversity of its genetic resistance and its application to the genetic control of the disease. Simultaneously to genetic improvements, and as a consequence of the close interaction between the pathogen and its host plant, an enormous variety of pathotypes has been described in all the sunflower-growing areas worldwide. Thus, the genetic control of sunflower downy mildew is an active research field subjected to continuous evolution and challenge. In practice, genetic resistance constitutes the base tier of Integrated Pest Management against sunflower downy mildew. The second tier is composed of elements related to crop management: rotation, removal of volunteer plants, sowing date, tillage. Biological control alternatives and resistance inducers could also provide additional restraint. Finally, the top tier includes chemical treatments that should only be used when necessary and if the more basal Integrated Pest Management elements fail to keep pathogen populations under the economic threshold.

Stemphylium Leaf Blight: A Re-Emerging Threat to Onion Production in Eastern North America.

Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is a foliar disease of onion worldwide, and has recently become an important disease in the northeastern United States and Ontario, Canada. The symptoms begin as small, tan to brown lesions on the leaves that can progress to defoliate plants. Crop loss occurs through reduced photosynthetic area, resulting in smaller, lower-quality bulbs. Leaf necrosis caused by SLB also can compromise bulb storage, as green leaves are required for the uptake of sprout inhibitors applied prior to harvest. The pathogen can overwinter on infested onion residue and infected volunteer plants. Asymptomatic weedy hosts near onion fields may also be a source of inoculum. Production of ascospores of the teleomorph (Pleospora allii) peaks in early spring in northeastern North America, often before the crop is planted, and declines rapidly as daily mean air temperatures rise. Conidia are usually present throughout the growing season. Application of fungicides is a standard practice for management of the complex of fungi that can cause foliar diseases of onion in this region. Recent assessments have shown that populations of S. vesicarium in New York and Ontario are resistant to at least three single-site mode-of-action fungicides. Three disease prediction systems have been developed and evaluated that may enable growers to reduce the frequency and/or number of fungicide applications, but the loss of efficacious fungicides due to resistance development within S. vesicarium populations threatens sustainability. The lack of commercially acceptable onion cultivars with sufficient resistance to reduce the number of fungicides for SLB also limits the ability to manage SLB effectively. Integrated disease management strategies for SLB are essential to maintain profitable, sustainable onion production across eastern North America.

Weed phytosociology in diversified soybean production systems

The knowledge of the impacts of the management practices used in each agricultural production system on the ecological interactions between commercial crops and weed populations can assist in the development of specific and sustainable integrated management strategies. This study aimed to assess weed communities in soybean in succession to second-crop corn and production systems with crop diversification in Northern Paraná State. The study was conducted during three agricultural years (2014/2017). Six treatments were setup: 1 – corn/soybean, corn/soybean, and corn/soybean), 2 – white oat/soybean, rye/corn, and wheat/soybean, 3 – oat + rye/soybean, oat + radish/corn, and congo grass/soybean, 4 – canola/corn, crambe/corn, and safflower/soybean, 5 – buckwheat/ radish/corn, bean/soybean, and buckwheat/oat/soybean, and 6 – wheat/corn + congo grass, canola/corn, and bean/soybean. The relative importance value index of each weed species and the soil cover (soil, straw, and weeds) were assessed. The experimental design consisted of randomized blocks with four replications of 300 m2 (20 × 15 m). The production systems white oat/soybean, rye/corn, and wheat/soybean; buckwheat/radish/corn, bean/soybean, buckwheat/oat/soybean; and wheat/corn+congo grass, canola/corn, bean/soybean had a suppressive effect on the species Commelina benghalensis. Euphorbia heterophylla and Digitaria horizontalis were the species most adapted to the assessed production systems. Seeds remaining from crambe and radish cultivations became volunteer plants in subsequent cultivations.

Reservoirs of plant virus disease: Occurrence of wheat dwarf virus and barley/cereal yellow dwarf viruses in Sweden

AbstractNon‐crop plants such as grasses and volunteer plants are an inseparable part of the flora of crop fields and can influence virus incidence in crop plants. The presence of grasses as virus reservoirs can lead to a higher probability of virus incidence in crop plants. However, the role of reservoirs as an inoculum source in agricultural fields has not been well studied for many viral diseases of crops. Grasses have been found to constitute potential reservoirs for cereal‐infecting viruses in different parts of the world. This study revealed that cereal‐infecting viruses such as wheat dwarf virus (WDV), barley yellow dwarf viruses (BYDVs), and cereal yellow dwarf virus‐RPV (CYDV‐RPV) can be found among ryegrass growing in or around winter wheat fields. Phylogenetic analysis showed that a WDV isolate from ryegrass was a typical WDV‐E isolate that infects wheat. Similarly, a ryegrass isolate of barley yellow dwarf virus‐PAV (BYDV‐PAV) grouped in a clade together with other BYDV‐PAV isolates. Inoculation experiments under greenhouse conditions confirmed that annual ryegrass of various genotypes can be infected with WDV to a very low titre. Moreover, leafhoppers were able to acquire WDV from infected ryegrass plants, despite the low titre, and transmit the virus to wheat, resulting in symptoms. Information from the grass reservoir may contribute to improving strategies for controlling plant virus outbreaks in the field. Knowledge of the likely levels of virus in potential reservoir plants can be used to inform decisions on insect vector control strategies and may help to prevent virus disease outbreaks in the future.

Sensitivity assessment and SDHC-I86F mutation frequency of Phakopsora pachyrhizi populations to benzovindiflupyr and fluxapyroxad fungicides from 2015 to 2019 in Brazil.

Fungicides of the succinate dehydrogenase inhibitors (SDHIs) group have been used in soybean to control Asian soybean rust (ASR) caused by Phakopsora pachyrhizi. Fungal populations with less sensitivity to SDHI fungicides have been reported since 2015. In this study, fungal sensitivity to benzovindiflupyr (BZV) and fluxapyroxad (FXD) was assessed using a total of 770 P. pachyrhizi populations sampled over four soybean growing seasons. Cross-resistance, intrinsic activity, and frequency of SDHC-I86F mutation were also analyzed. The average effective concentration to inhibit 50% (EC50 ) and SDHC-I86F frequency increased over the 2015/2016, 2016/2017, 2017/2018 and 2018/2019 soybean-seasons. Fourteen P. pachyrhizi populations had the EC50 value above 10mg L-1 for both carboxamides. No difference was found in intrinsic active to BZV and FXD fungicides for sensitive P. pachyrhizi populations. For P. pachyrhizi classified as less sensitive BZV showed the highest fungitoxicity effect. High frequency of the C-I86F mutation was observed in samples collected in volunteer soybean plants. The maximum frequency of SDHC-I86F mutation in the population was 50% and resulting in ASR populations with low sensitivity to SDHIs. A low correlation between bioassay and SDHC-I86F mutation was observed possible due to the dikaryotic nature of rust fungi or other mutations in the other succinate dehydrogenase subunits. The present work provides an overview of a large sampling size of P. pachyrhizi populations and their performance over the four crop seasons. The high frequency of SDHC-I86F mutation and low sensitivity to SDHIs are widely distributed in the main soybean growing regions in Brazil and present in volunteer plants in the soybean-free period. Further detailed studies are needed to identify novel point mutations affecting the effectiveness of SDHIs. © 2021 Society of Chemical Industry.

An Overview of the Epidemiology of Phakopsora pachyrhizi in the State of Mato Grosso, Brazil

This review seeks to expand the knowledge about the epidemiology of Asian sybean rust in the state of Mato Grosso and contribute to ensuring the economic sustainability of soybean crop. It is discussed the Phakopsora pachyrhizi potential of dispersal from Asia to South America and finally to Mato Grosso state. The origin of the Asian soybean rust inoculum within Mato Grosso is addressed by the survival in volunteer and soybean weed plants (Pitelli, 2015) in other crops such as cotton. Data on the adverse environmental effect on the soybean plants survival are shown mainly the water deficit from June to August. Reports on the effect air temperature and mainly solar radiation on the mortality of airborne spores during their anemophilous spread on sunny days are also discussed. This increase of knowledge aims to make the soybean-free period more efficient by the knowledge on the soybean plants survival and on the fungus viability in the month of August. Due to the proximity of soybean farms, during the soybean-free period, in other states (Tocantins, Goiás, Rondônia, etc.) and in other neighbor countries we discuss the likelihood that inoculum in the state may also originate in out-of-state crops during the Mato Grosso soybean-free period.

Herbicides Efficacy against Volunteer Oilseed Rape as Influenced by Spray Solution pH

The pH of the spray liquid is one of the factors influencing the efficacy of herbicides. Adjusting the appropriate parameters of the spraying liquid may reduce the consumption of pesticides, which is in line with the currently introduced legal standards and society’s requirements. In the greenhouse experiment, the influence of herbicides containing mesotrione, nicosulfuron, rimsulfuron, bromoxynil, and a mixture of nicosulfuron, rimsulfuron, and mesotrione on the efficacy of oilseed rape control was investigated. Oilseed rape (Brassica napus L. ssp. oleifera), apart from being an important crop, can become a nuisance weed in many fields as form of volunteer plants. Visual assessment, reduction of fresh weight, and chlorophyll fluorescence were performed. Individual herbicides influenced the tested parameters to a different extent. The pH of the spray liquid influenced the efficacy of individual plant protection products. The highest herbicidal efficacy in relation to the tested plants was observed in the case of combinations in which mesotrione was applied at a reduced and increased pH, nicosulfuron applied in an acidic and alkaline environment, rimsulfuron without pH modification, and all treatments in which bromoxynil was applied. The herbicides containing mesotrione and bromoxynil had the greatest impact on the photosystem II activity.

Evolution of Physico-Chemical Properties, Microbial Biomass and Microbial Activity of an Urban Soil after De-Sealing

Recovery of soil fertility after de-sealing of urban soils is still poorly known. This work studied the time-related dynamics of soil physico-chemical and biochemical endpoints of urban soil in the city in Naples (Southern Italy), de-sealed for different time during construction works, that underwent colonization by volunteer plants. The results showed de-sealing decreased the soil bulk density and the soil pH value, increased the electrical conductivity (EC), total organic C (TOC) and extractable carbohydrates (TEC), total and inorganic N contents, soil basal respiration (SBR), soil microbial biomass C (MBC) and soil microbial biomass N (MBN), the substrate induced respiration (SIR) value, and enzyme activities involved in C, N, P and S mineralization. The TEC, total and inorganic N, SBR and microbial biochemical endpoints were higher in the de-sealed soils than those of an arable soil of the same area. The results show that de-sealed urban soils rapidly increase their physical, chemical and biological fertility even with no intervention, especially when they are colonized by volunteer plants.

Survival of Pratylenchus brachyurus under dry soil conditions

Pratylenchus brachyurus, a root-lesion nematode, depends on host plants for growth and survival. Weeds, volunteer plants, and crop root residues may act as reservoirs for the parasite in the field, but little is known about the ability of P. brachyurus to survive in the absence of a host. This study aimed to evaluate P. brachyurus survival and infectivity in artificially and naturally infested soil under dry conditions. Two experiments were conducted, the first using artificially infested soil and the second using naturally infested soil. Soil samples were inoculated with a nematode suspension or infected root fragments. At 0, 30, 60, and 90 days post-inoculation, pots were planted with nematode-susceptible maize and soybean. Fallow pots were also analyzed. Nematode survival, infectivity, and morphology were determined 30 days after planting. P. brachyurus showed enhanced survival in soil in the presence of root fragments. However, inoculation method had no effect on the ability of surviving nematodes to infect host roots. Parasites showed signs of anhydrobiosis (C-shaped or tightly coiled body) after 90 and 120 days under dry conditions.

Increased BnaMFT-transcript level is associated with secondary dormancy in oilseed rape (Brassica napus L.)

Brassica napus cultivars have little or no primary dormancy; however, they are prone to secondary dormancy induction. Secondary dormant seeds can produce volunteer plants, which can result in genetic contamination, reduced quality and biosafety issues. However, information regarding the molecular mechanism underlying secondary dormancy is limited. The MOTHER OF FT AND TFL1 (MFT) gene, which is evolutionarily conserved in the plant kingdom, acts in a complex gene network in the seed dormancy or germination processes. In this study, we identified four B. napus genes that share high homology with AtMFT, named as BnaMFT. Analyses of cis-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements, and various stress- and hormone-responsive elements. Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed, with peaks at 35–42 days after pollination. BnaMFTs were not sufficient for primary dormancy; however, they were significantly enhanced by secondary dormancy induction with PEG6000 treatment. Moreover, BnaMFT transcripts were elevated by treatment with abscisic acid (ABA), which is known to be accumulated during secondary dormancy. These results collectively suggest that increased BnaMFT transcription levels are associated with secondary dormancy induction in an ABA-dependent manner in B. napus.