Hoeing as a Possibility for Mechanical Weed Control in Winter Oilseed Rape (Brassica napus L.)

The framework conditions for chemical weed control in oilseed rape (OSR) are becoming increasingly unfavorable in Central Europe. On the one hand, weed resistance is spreading and, on the other, there is a growing social desire to reduce or eliminate the use of chemical crop protection products. In a field experiment, hoeing, as a weed control measure performed two times per growing season (one time in autumn and one time in spring) in oilseed rape (Brassica napus; two varieties), was compared to chemical control by herbicides and a combination of hoeing and herbicide application (five treatments altogether). The chemical control by herbicides consisted of a broad-spectrum pre-emergence treatment and a post-emergence graminicide application. The trial was set up in each of three periods (years 2014/2015, 2015/2016, and 2016/2017) at the experimental station Ihinger Hof, University of Hohenheim, Stuttgart, Germany. The effect of the treatments on weed plant density, weed biomass at the time of harvesting, and on OSR grain yield was investigated. Weed plant density was measured four times per trial year, each time before and after hoeing. In 2015/2016 after spring hoeing, and in 2016/2017 at all data collection times, weed plant density was significantly higher in hoeing without herbicide application than in the other variants. No significant differences occurred at the other data collection times. The weed plant density ranged from 0.5 to 57.8 plants m−2. Regardless of the trial year, pure hoeing always resulted in a significantly higher weed biomass at the time of harvesting than the herbicide applications or the combinations. The weed biomass at the time of harvesting ranged between 0.1 and 54.7 g m−2. No significant differences in grain yield between hoeing and herbicide application occurred in all three trial years. According to the results, hoeing is a suitable extension of existing integrated weed control strategies in OSR.

Deep Learning-Based Object Detection System for Identifying Weeds Using UAS Imagery

Current methods of broadcast herbicide application cause a negative environmental and economic impact. Computer vision methods, specifically those related to object detection, have been reported to aid in site-specific weed management procedures for targeted herbicide application within a field. However, a major challenge to developing a weed detection system is the requirement for a properly annotated database to differentiate between weeds and crops under field conditions. This research involved creating an annotated database of 374 red, green, and blue (RGB) color images organized into monocot and dicot weed classes. The images were acquired from corn and soybean research plots located in north-central Indiana using an unmanned aerial system (UAS) flown at 30 and 10 m heights above ground level (AGL). A total of 25,560 individual weed instances were manually annotated. The annotated database consisted of four different subsets (Training Image Sets 1–4) to train the You Only Look Once version 3 (YOLOv3) deep learning model for five separate experiments. The best results were observed with Training Image Set 4, consisting of images acquired at 10 m AGL. For monocot and dicot weeds, respectively, an average precision (AP) score of 91.48 % and 86.13% was observed at a 25% IoU threshold (AP @ T = 0.25), as well as 63.37% and 45.13% at a 50% IoU threshold (AP @ T = 0.5). This research has demonstrated a need to develop large, annotated weed databases to evaluate deep learning models for weed identification under field conditions. It also affirms the findings of other limited research studies utilizing object detection for weed identification under field conditions.

Brazilian Peppertree Control

This publication presents management recommendations for the Brazilian peppertree. It contains information about Brazilian peppertree biology, herbicide application techniques, and the status of biological control. Written by K. T. Gioeli, S. F. Enloe, C. R. Minteer, D. M. Lieurance, and K. A. Langeland, and published by the UF/IFAS Agronomy Department, revised November 2021.

Assessment of Safety Measures and Costs Effect of Herbicide Usage among farmers in Mokwa Local Government Area, Niger State

Weed is one of the most important constraints that limit food production. Checking weeds with herbicides could be harmful if safety precautions are not followed by users. This study assessed the use of safety practices and costs associated with herbicide use among farmers in Mokwa Local Government Area of Niger State, Nigeria. Multistage sampling technique were used to select 160 respondents that were interviewed. Data were analyzed using descriptive statistics and costs addition. Results revealed that contact (Paraquat), selective (2,4-Dimethylamine), non-selective systemic (Glyphosates) and mixture of (2-4-Dimethylamine) and (Glyphosate or Paraquat) were used by respondents to control weeds. The rates of herbicide application ranged from 2.0 and 3.8 litres per hectare with a mean rate of 3.1 litres per hectare. The mean index of Safety practices was 0.68, an indication of high use of safety practices. Use of hand gloves, face masks, eye glasses and rain boots was low. Herbicide containers and left over herbicide solutions were not properly disposed by a larger proportion of respondents. Costs of herbicide usage for major crops cultivated by respondents varies from N4,859 to N7,025 per hectare. Implementation of extension programmes on safety measures in usage of herbicides and sensitization on farmers on protective tools usage were recommended.

Application of precision farming technologies for chemical protection of grain crops

The current trend of development of agricultural production brings heightened requirements to the quality and safety of products forcing the producers to change the technologies profoundly with providing balance between gross output of production and its safety, and maintaining the stability of agro-ecosystem. The main directions of implementation of this trend is application of technologies of precision farming which constitutes in pre-dosed and addressed fertilizing and application of chemical materials to protect plants. One of the directions of efficiency improvement in the sphere of plant protection is the application of GPS-navigation which monitors the quantity of applied liquid and moving aggregates used for herbicide application. While carrying out the study of efficiency of application of the parallel driving system with the use of GPS-navigation during the chemical weeding of barley seeds of the sort “Otra” in conditions of the Vologda region it was found out that application of the system of parallel driving allowed reducing the amount of sections with the repeated herbicide treatment. This leads to the lowering of quantity of applied herbicides and positively affects the grain crop yield providing the reduction of costs for dilution to treat more than 1, 2 times.

Effect of fertilizer and cultivation systems and herbicide application on soil biological activity under spring barley cultivation and its yield

The results of the research devoted to the change of the biological composition of the soil under the conditions of activation of microbiological vital activity and increase in the number of earthworms in the technology of spring barley cultivation are presented. It was found that the organic system of growing crops against the background of manure, cereal straw and green manure in comparison with the organo-mineral system obtained a positive dynamics of decomposition of linen tissue and the development of earthworms in the soil.The highest grain yield was formed by agrocenosis of spring barley with the introduction of Lancelot 450 WG – 0.033 kg·ha–1 + Axial 50 EC – 1 dm3·ha–1 (tube exit phase) – 4900 kg·ha–1 and 4700 kg·ha–1 for organo-mineral and organic fertilizer systems in accordance.

Modulation of Physiological Stress Response of Triticum aestivum L. to Glyphosate by Brassinosteroid Application

The potential of brassinosteroids to modulate the physiological responses of winter wheat (Triticum aestivum L.) to herbicide stress was evaluated. Young winter wheat seedlings were treated with 24-epibrassinolide (EBL) and 24 h later were sprayed with glyphosate. The physiological responses of treated plants were assessed 14 days after herbicide application. Wheat growth was noticeably inhibited by glyphosate. The herbicide application significantly increased the content of the stress markers proline and malondialdehyde (MDA) evidencing oxidative damage. The content of phenolic compounds was decreased in the herbicide-treated plants. Slight activation of superoxide dismutase (SOD) and catalase (CAT) and considerable increase of glutathione reductase (GR) and guaiacol peroxidase (POX) activities were found. Increased POX and glutathione S-transferase (GST) activities were anticipated to be involved in herbicide detoxification. Conjugation with glutathione in herbicide-treated plants could explain the reduction of thiols suggesting unbalanced redox state. EBL application did not alter the plant growth but a moderate activation of antioxidant defense (POX, GR, and CAT activities and phenolic levels) and detoxifying enzyme GST was observed. The hormonal priming provoked a slight decrease in MDA and proline levels. The results demonstrate that EBL-pretreatment partly restored shoot growth and has a potential to mitigate the oxidative damages in glyphosate-treated plants through activation of the enzymatic antioxidant defense and increase of the phenolic compounds.

Optimization of Spray Fluid for Herbicide Application for Drones in Irrigated Maize (Zea mays L.)

A field experiment was conducted in a randomized complete block design to screen the optimum spray fluid of herbicide application for drone based on visual toxicity and weed control efficiency in maize (Zea mays L.) during the summer season (March 2021) at eastern block farms of Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu. Three herbicide treatments namely Atrazine, Tembotrione and 2, 4-D with recommended dosages, 75% and 125% as pre-emergence herbicides applied on 3 days after, early post-emergence herbicides applied on 15 days after sowing and post-emergence applied on 25 days after sowing respectively. Totally thirty treatments with different spray fluids such as 500, 400, 300, 200, 100, 80, 60, 40, 30 L ha-1 and 20 L ha-1 were replicated three times. The study revealed that T5- Recommended dosage of pre emergence Atrazine – early post emergence Tembotrione – post emergence 2, 4-D (spray fluid 100 L of water ha-1),T6- Recommended dosage of pre emergence Atrazine – early post emergence Tembotrione–post emergence 2, 4-D (spray fluid 80 L of water ha-1), T7- Recommended dosage of pre emergence Atrazine – early post emergence Tembotrione – post emergence 2, 4-D (spray fluid 60 L of water ha-1) and T8- Recommended dosage of pre emergence Atrazine – early post emergence Tembotrione – post emergence 2, 4-D (spray fluid 40 L of water ha-1) produced the best results with respect to phytotoxicity and weed control efficiency. Based on the results it was concluded that the application of spray fluid 80 L ha-1 was optimum for herbicide application through drones with recommended dosage pre emergence Atrazine 1 kg a.i ha-1 on 3 days after sowing – early post emergence Tembotrione 120 g a.i ha-1 on 15-20 days after sowing - post emergence 2, 4-D 1 kg a.i ha-1 on 30 - 35 days after sowing.

Sensitivity of lettuce cultivar Lucy Brown to pre-planting herbicide application

ABSTRACT Due to the low availability of herbicide active ingredients, the chemical weed management in lettuce crop is a challenge. The aim of this study was to evaluate the sensitivity of lettuce to the pre-planting application of the herbicides flumioxazin and trifluralin alone or in tank-mixture in lettuce, Lucy Brown cultivar. Two experiments were conducted. In experiment A, the soil was tilled before the herbicide application and it was tilled again before seedling transplanting. In experiment B, the soil was tilled just once before the herbicide application. The experimental design was in randomized blocks in a factorial scheme (3x3) +1 (2 factors with 3 levels and an additional control) with 4 replicates. We applied flumioxazin (120 g ha-1), trifluralin (450 g ha-1) and flumioxazin + trifluralin (120 + 450 g ha-1) in three different seasons before transplanting (0, 7 and 14 days). Lettuce productivity after trifluralin application (48.4 t ha-1) was higher than after flumioxazin application (16.8 t ha-1) in experiment A. In experiment B, flumioxazin decreased the number of lettuce leaves (25.6) at 14 DAT; no differences in lettuce productivity were verified, though. The herbicide trifluralin caused lower levels of phytotoxicity and was the most selective between the treatments when applied in the three seasons in both experiments.