A multi-year study was carried out at two citrus groves with mature trees in Southwest Florida in the United States to evaluate the effects of cover cropping on the citrus inter-row as a sustainable weed management strategy in the Florida citrus production system. Two cover crop (CC) mixes (legume + nonlegume species and only non-legume species) were compared with a no-CC grower standard management (GSM) that utilized the herbicide paraquat for weed suppression in the citrus tree inter-row spaces. We gathered data on the biomass and density of both cover crops and weeds, during the spring and summer/fall CC planting seasons throughout the study years. Both mixes of CCs effectively reduced weed density in the citrus inter-row by 58 to 99% (P<0.05), depending on the growing season and study locations, compared to GSM. Additionally, there were no significant differences observed between the different CC mixes. Similarly, both CC mixes reduced the weed biomass by 95 to 99% (P<0.05) in the citrus inter-row compared to the GSM. However, weed suppression by CCs varied between growing seasons, mainly due to differences in germination and establishment of the CCs in each season.

Inter-row weed control is used in a wide range of crops, traditionally applied via physical cultivation or banded herbicide application. However, these methods may result in crop damage, herbicide resistance development, or off-target environmental impacts. Electric inter-row weed control presents an alternative, though its potential impact on crop yield requires further investigation. One of the modes of action of electric weed control is the continuous electrode-plant contact method, which passes a current through the weed and into the roots. As the current passes into the roots, it can potentially disperse through the soil to neighbouring root systems. Such off-target current dispersion, particularly in moist topsoil with low resistance, poses potential concern for neighbouring crops when electric inter-row weed control is applied. This research evaluated the continuous electrode-plant contact method, using a ZassoTM XPower machine, in comparison with mowing, across three trials conducted in 2022 and 2023. Both treatments were used to remove target lupin plants adjacent to a row of non-target lupin. Electric weed control was applied to plants in dry soil or following a simulated rainfall event. The trials demonstrated that electric weed control and mowing did not reduce density and biomass of neighbouring non-target lupin plants compared to the untreated control. Likewise, pod and seed production, grain size and protein, as well as grain germinability and vigour of the resulting seedlings was not reduced by these weed control tactics. This research used technology that was not fit for purpose in broad scale grain crops but concludes that electric weed control via the continuous electrode-plant contact method or mowing did not result in crop damage. Therefore, it is unlikely that damage will occur using commercial-grade electric weed control or mowing technology designed for large acreage inter-row weed control, thus offering non-chemical weed management options.

Knotroot foxtail [Setaria parviflora (Poir.) Kerguélen], a perennial Setaria species, is becoming more problematic in forage and grazing systems across the southeastern United States. Knotroot foxtail reproduces through the production of rhizomes and seeds, further complicating management strategies. Significant knowledge gaps exist regarding the biology and control of this species. This research aimed to understand the influence of burial depth on S. parviflora propagules and the physiological differences between it and other Setaria species. Experiments were conducted between October 2019 and February 2021 in Clarke County, GA, to investigate the influence of burial depth (1, 2, 4, 8, and 16 cm) on the emergence and growth of knotroot foxtail rhizomes and seeds. Zero emergence was estimated at 8.7, 10.8. and 11.2 cm for small rhizomes, large rhizomes, and seeds, respectively. Therefore, producers could implement tillage events to a depth of 11.2 cm or greater to control knotroot foxtail. A separate study compared knotroot foxtail, yellow foxtail [Setaria pumila (Poir.) Roem. & Schult.], green foxtail [Setaria viridis (L.) P. Beauv.], and giant foxtail (Setaria faberi Herrm.) plant morphology. Despite similar appearances aboveground, yellow, and knotroot foxtail had different total and belowground biomass two to five months after emergence, which suggest differences in root formation and perennialization of knotroot foxtail. The present research determined that burying propagules using tillage could be included in management recommendations concerning knotroot foxtail; however, it should be complemented with herbicide applications during the growing season to assist in controlling foxtail plants produced by seeds.

Buffalobur (Solanum rostratum Dunal) () is an invasive weed in China, identifying its pathogens is crucial for developing effective biological control measures. In this study, leaf samples from S. rostratum showing typical disease symptoms were collected in Liaoning and Jilin provinces, China. The isolated fungal pathogens were identified based on their morphological characteristics and by using molecular biology techniques. Pathogenicity was assessed by artificially inoculating spore suspensions from the fungal pathogen onto the seeds, isolated leaves, and plants of S. rostratum. The safety of the fungal pathogens for eight plant species was also evaluated. We then identified the following five fungal pathogens causing disease in S. rostratum in Liaoning and Jilin provinces: Alternaria alternata, Epicoccum sorghinum, Fusarium equiseti, Curvularia hawaiiensis, and Nigrospora oryzae. These fungal pathogens exhibited pathogenicity, with N. oryzae exhibiting the strongest pathogenicity and highest safety. N. oryzae demonstrated the highest inhibition rate against the radicle germination length of S. rostratum and showed robust pathogenicity towards both isolated leaves and plants. Notably, despite inducing mild reactions in corn, sorghum, rice, and tomatoes, N. oryzae did not impose any detrimental effects on the growth of these plants.

Machine vision-based herbicide applications relying on object detection or image classification deep convolutional neural network (DCNN) demand high memory and computational resources, resulting in lengthy inference times. To tackle these challenges, this study assessed the effectiveness of three teacher models, each trained on datasets of varying sizes, including D-20k (comprising 10,000 true positive and true negative images) and D-10k (comprising 5,000 true positive and true negative images). Additionally, knowledge distillation was performed on their corresponding student models across a range of temperature settings. After the process of student-teacher learning, the parameters of all student models were reduced. ResNet18 not only achieved higher accuracy (ACC≥0.989) but also maintained higher frames per second (FPS≥742.9) under its optimal temperature condition (T=1). Overall, the results suggest that employing knowledge distillation on the machine vision models enabled accurate and reliable weed detection in turf while reducing the need for extensive computational resources, thereby facilitating real-time weed detection and contributing to the development of smart, machine vision-based sprayers.

Barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is increasingly infesting imidazolinone-tolerant (IMI-T) rice fields in China, imazamox resistance of E. crus-galli has become the major concern for weed management in IMI-T rice fields. In this study, the susceptible population JLGY-3 (S) and the suspected resistant population JHXY-2 (R) collected from IMI-T rice fields were used as research subjects. When treated with imazamox, JHXY-2 (R) population showed a high level of herbicide resistance with a resistance index (RI) of 31.2. JHXY-2 (R) was cross-resistant to all five acetolactate synthase (ALS) inhibitors from different chemical families, but sensitive to herbicides inhibiting acetyl-CoA carboxylase (ACCase). In order to understand the reason why JHXY-2 (R) was resistant to imazamox, we performed experiments to characterize potential TSR and NTSR mechanisms. A trp-574-leu amino acid mutation in ALS and low imazamox ALS sensitivity were the main mechanism underlying imazamox resistance in this JHXY-2 (R) population. There was no significant difference in ALS gene expression and ALS protein abundance between R and S populations. High-performance liquid chromatography-tandem mass spectrometry analysis showed enhanced metabolism of imazamox in JHXY-2 (R), which was in contrast to the results of pretreatment with a metabolic enzyme inhibitor. Treatments with the P450/GST inhibitors did not alter the resistance level of JHXY-2 (R) against imazamox. To further clarify the NTSR mechanism of JHXY-2 (R), transcriptome sequencing showed that there was almost no significant difference in the expression of P450 and GST metabolic enzyme genes between R and S populations, and only GST-U1 showed a significant induction in R population. In conclusion, amino acid mutation and higher enzyme activity of ALS are the main causes of imazamox resistance in JHXY-2 (R). However, given the differences in imazamox residues in the leaves of the E. crus-galli, there may still be undetectable NTSR that are causing imazamox resistance in the R population.

Plant names carry a significant amount of information without providing a lengthy description. This is an efficient shorthand for scientists and stakeholders to communicate about a plant, but only when the name is based on a common understanding. It is standard to think of each plant having just two names, a common name and a scientific name, yet both names can be a source of confusion. There are often many common names that refer to the same plant, or a single common name that refers to multiple different species, and some plants are without a common name at all. Scientific names are based upon international standards; however, when there is not agreement in the taxonomy, two scientific names may be used to describe the same species. Weed scientists and practitioners can easily memorize multiple plant names and know that they refer to the same species, but when we consider global communication and far-reaching databases, it becomes very relevant to consider two sides of this shift: 1) A need for greater standardization (due to database management and risk of lost data from dropped cross-referencing) and 2) the loss of local heritage which provides useful meaning through various common names. In addition, weed scientists can be resistant to changing names that they learned or frequently use. The developments in online databases and reclassification of plant taxonomy by phylogenetic relationships have changed the accessibility and role of the list of standardized plant names compiled by the Weed Science Society of America (WSSA). As part of an attempt to reconcile WSSA and USDA common names for weedy plants, the WSSA Standardized Plant Names Committee recently concluded an extensive review of the Composite List of Weeds common names and had small changes approved to about 10% of the list of over 2800 distinct species.