Mesotrione: a new preemergence herbicide option for wild radish (Raphanus raphanistrum) control in wheat

Wild radish is the most problematic broadleaf weed of Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively control wild radish in wheat. The initial dose response pot trials determined that at the highest mesotrione rate of 50 g ha−1, PRE application was 30% more effective than POST on wild radish. This same rate of mesotrione POST resulted in a 30% reduction in wheat biomass compared to 0% for the PRE application. Subsequent, mesotrione PRE dose response trials identified a wheat selective rate range of >100 and < 300 g ai ha−1 that provided greater than 85% wild radish control with less than 15% reduction in wheat growth. Field evaluations confirmed the efficacy of mesotrione at 100 to 150 g ai ha−1 in reducing wild radish populations by greater than 85% following PRE application and incorporation by wheat planting. Additionally, these field trials demonstrated the opportunity for season-long control of wild radish when mesotrione PRE was followed by bromoxynil POST. The sequential application of mesotrione, an HPPD-inhibiting herbicide, PRE followed by bromoxynil, a PS II-inhibiting herbicide POST has the potential to provide 100% wild radish control with no effect on wheat growth.

Winter Forage Crop Harvest Time Impacts Regeneration of the Annual Weeds Barley Grass, Annual Ryegrass and Wild Radish

Barley grass (Hordeum spp.) is a short-lived annual weed which competes with preferred crop and pasture species and frequently contaminates wool and carcasses, and irritates the ears, eyes and noses of sheep. Barley grass, annual ryegrass (Lolium rigidum L.) and wild radish (Raphanus raphanistrum L.) are annual winter crop weeds which reduce grain yield through competition. In three consecutive years (2015 to 2017) cereal, legume and cereal/legume forage crops were grown and harvested in early October, late October or early November consistent with an early silage harvest (ES), late silage harvest (LS) or hay cut (H). A spring wheat cultivar was sown over each site in the following year (2016 to 2018). Weed density was recorded during the forage crop and wheat phases. Forage crop weed populations varied between years. Late paddock preparation for sowing in 2015 effectively eradicated barley grass from all forage crops; however, the competitiveness of legume and cereal/legume crops against annual ryegrass was reduced. In contrast, legume and cereal/legume mixtures tended to have higher barley grass densities than cereal crops in 2016 and 2017, when paddock preparation was earlier. Cutting in October 2015 reduced annual ryegrass and wild radish populations in 2016 wheat by 92.0% and 86.7%, respectively. In 2017 and 2018, regrowth and subsequent seed set following cutting appeared to negate cutting time effects for all crop and crop/legume combinations. Late paddock preparation, an early October forage harvest and effective regrowth control provided the best opportunity for barley grass, annual ryegrass and wild radish control in a single year.

Phenotypic plasticity in plant defense across life stages: Inducibility, transgenerational induction, and transgenerational priming in wild radish

As they develop, many plants deploy shifts in antiherbivore defense allocation due to changing costs and benefits of their defensive traits. Plant defenses are known to be primed or directly induced by herbivore damage within generations and across generations by long-lasting epigenetic mechanisms. However, little is known about the differences between life stages of epigenetically inducible defensive traits across generations. To help fill this knowledge gap, we conducted a multigenerational experiment to determine whether defense induction in wild radish plants was reflected in chromatin modifications (DNA methylation); we then examined differences between seedlings and reproductive plants in current and transgenerational plasticity in chemical (glucosinolates) and physical (trichomes) defenses in this species. Herbivory triggered genome methylation both in targeted plants and their offspring. Within one generation, both defenses were highly inducible at the seedling stage, but only chemical defenses were inducible in reproductive plants. Across generations, herbivory experienced by mother plants caused strong direct induction of physical defenses in their progeny, with effects lasting from seedling to reproductive stages. For chemical defenses, however, this transgenerational induction was evident only in adults. Transgenerational priming was observed in physical and chemical defenses, particularly in adult plants. Our results show that transgenerational plasticity in plant defenses in response to herbivore offense differs for physical and chemical defense and changes across plant life stages.

TREATMENT OF LEAD CONTAMINATED WASTE SLUDGE USING THE WILD RADISH VEGETABLE SPECIES Raphanus raphanistrum

Sludge generated in the treatment of urban wastewater must be properly treated as it may contain concentrations of heavy metals or the presence of pathogenic microorganisms. The wastewater treatment plant in the main parish of Penipe, Chimborazo province, Ecuador, consists of an Imhoff tank in whose sedimentation chambers the waste sludge from physical treatment is digested under anaerobic conditions. The sludge is discharged into an open-air drying bed and does not receive treatment to stabilize it. Laboratory analysis determined that the sludge contains 24.23 mg.kg-1 of lead and is considered a potentially hazardous waste. The aim of the research is to treat the contaminated sludge by means of phytoextraction. The plant species known as wild radish (Raphanus raphanistrum) was sown in the residual mud and the treatment was biomonitoring for 91 days. Mud samples were taken every 15 days and by laboratory analysis a decrease in lead concentration was identified, identifying a root absorption efficiency of 16.40%.

Population Distribution of Wild Radish (Raphanus Raphanistrum L.) Weed and Soil Depth of Seed Bank Across Different Land-Use Types in Horro District, Western Oromia, Ethiopia

Background: Wild radish (Raphanus raphanistrum L.) is an invasive weed in Ethiopia and hurting different land use types in the Horro district of the study area and fact, more research has not been done yet on the weed is highly infested and persisted for three decades. Therefore, this study was conducted to assess the weeds flora and seed bank status across different land use types in the Horro district of western Oromia, Ethiopia. Three locations and from each location five different land use were purposively selected and a 1m2 area of quadratic sampling techniques was used to record weed flora. From each quadrat, soil samples were taken having two soil depth levels (0-15cm and >15-30cm) to evaluate the soil seed bank of weeds. Results: The data of wild radish weed in different location and different land use types both field survey and greenhouse experiments were found a statistically significant difference (p<0.05) among the target action of land use types but there was found no significant difference among soil depths. More all less, the highest wild radish population was recorded from grazing land land followed by wheat crop land and among the locations, Gitilo Dale has the highest weed density. Among the weed flora, again wild radish was highly dominated weed species than the other weed species in all land use types and locations. From soil seed bank status of soil depth, high weed population was recorded at 0-16cm of second season weed emergence from pot and Gitilo Dale was the highest infected location at this season, while barley crop land was the highest infected among land use types in first season of weed emergence from pot. Among the weed species were recorded from soil depth, again wild radish was highly dominated in both seasons. The population of weed flora per quadrat was directly proportion with population recorded from soil depth that emerged from pot. Conclusions: This study has highly verified that this area has highly infected by wald radish (Raphanus raphanistrum) and there could be a source of weed seed. Generally, the concerned bodies should have to be given attention which should need immediate intervention strategies to mitigate the negative impacts of weed otherwise the area will be out of production soon. Therefore, an extensive integrated weed management strategies should be applied in all phases of cropping systems to sustain environment and reduce this weed in the future.

2,4-D and dicamba removal from the surface of plastic mulch using overhead irrigation: analytical analysis and cucurbit bioassay crop response

Glyphosate and paraquat are effective preplant burndown herbicide options for multi-cropped vegetable production on plastic mulch, but problematic weeds such as wild radish, cutleaf eveningprimrose, annual morningglory, or horseweed may not be adequately controlled with these herbicides alone. 2,4-D and dicamba could help control these troublesome weeds prior to planting if they can be removed from plastic mulch for avoiding crop damage. Treatments included 2,4-D (1,065 and 2,130 g ae ha−1) and dicamba (560 and 1,120 g ae ha−1) applied broadcast over plastic mulch a day before transplanting. Just before transplanting, treatments received overhead irrigation at 0.76 cm or no irrigation. Plastic mulch samples were collected at application and planting to determine herbicide presence using analytical techniques, and cantaloupe and zucchini squash were subsequently transplanted on the plastic beds. Analytical UHPLC analysis determined 88-99% of the initial herbicide concentration was present at crop planting when irrigation was not implemented. At most, a 1/50 rate of dicamba and a 1/500 rate of 2,4-D was present at planting when overhead irrigation was applied prior to transplanting. Maximum cantaloupe and squash injury from 2,4-D with irrigation was 10% and did not influence plant growth, biomass, or yield. For dicamba with overhead irrigation, cantaloupe injury reached 35%, vine lengths were reduced 24% and maturity was delayed while squash injury ranged from 9 to 12% without influencing growth or yield. Without irrigation to wash herbicides from the mulch prior to planting, 60 to 100% injury of both crops occurred with both herbicides. Zucchini squash was more tolerant to dicamba compared to cantaloupe. Results demonstrated that 2,4-D can be adequately removed from the surface of plastic mulch with irrigation while a single irrigation event was not sufficient to remove dicamba.

Weed control and soybean agronomic performance in response to application of sulfentrazone + diuron in pre-emergence

The use of pre-emergent herbicides is an important tool in weedmanagement. Sulfentrazone + diuron mixture was recently launched ontothe market. The objectiveof this work was to evaluate the weed control and the agronomic performance of soybean in response to application of sulfentrazone + diurondoses in pre-emergence. The experiment was conducted in Londrina PR, in an oxisol. The treatments were doses ofsulfentrazone + diuron (62 + 123, 123 + 245, 184 + 368, 245 + 490, 306 + 613 e 368 + 735 g a.i.ha-1). In addition to these treatments, isolated applications of sulfentrazone (245 g a.i.ha-1) and diuron (490 g a.i.ha-1) were evaluated, as well as a weedyand aweed-freecontrol. For the weed control, the wild radish(Raphanus raphanistrum)and itchgrass (Rottboellia cochinchinensis) emergencewere evaluated. In soybean, photosystem II (PSII)activity, stand, plant height, number of podsper plant, height of insertion of the first pod, number of nodes per plant, mass of a thousand grains and grain yield were evaluated. Results show that the mixture of sulfentrazone + diuron resulted in less than 50% wild radish control, regardless of the dose evaluated. However, for itchgrass, the control was greater than 90% in doses from 123 g sulfentrazone + 245g diurona.i.ha-1. Regarding thesoybeancrop, in doses from 245 g sulfentrazone + 490 g diuron a.i. ha-1 there was a greater number of pods per plant and higher grain yield, of about3,000 kg ha-1. The application of herbicides led to a transient inhibition of PSIIactivity, which did not result in a reduction in crop grainyield, indicating plant recovery. Therefore, the mixture of sulfentrazone + diuron is a good alternative for the weed management in pre-emergence of soybean, and should be positioned according to the history of fieldinfestation.