American sloughgrass [Beckmannia syzigachne (Steud.) Fernald] is a troublesome wheat weed. We tested the germination of B. syzigachne seeds under different temperatures with growth chambers (12 h dark/12 h light, 12000 lx), simulating those during the sowing periods of early- (25/15 C), ordinary- (20/10 C), late- (15/5 C), and very late-sown winter wheat (5/0 C). We also tested the accumulated temperatures required for seedling growth to the 2- to 5-leaf stages, using 225 populations collected from wheat fields in eastern China. The average 1000-seed weight of the 225 populations was 1.2 ± 0.01 g. Overall populations tested did not show seed germination after 21 days of treatment (DAT) at 5/0 C or constant 30 C. At 14 DAT with 25/15 C, 20/10 C, and 15/5 C, the mean germination rates were 85.4%, 6.4%, and 0.1%, respectively. These rates increased to 99.9%, 58.6%, and 21.7% at 21 DAT. Populations collected from lower latitude regions germinated significantly faster (P < 0.05) under optimal conditions. Accumulated temperatures required for growing the 2nd, 3rd, 4th, and 5th leaf were 139.0 ± 1.0, 127.8 ± 1.0, 115.6 ± 1.0, and 98.9 ± 0.7 C, which showed a significant decreasing trend. The narrower optimal temperature range for B. syzigachne seed germination and higher thermal requirements for early seedling growth constrain its distributions, while the heterogeneous seed germination facilitates its infestations in wheat planting areas in eastern China.

Pollinators are susceptible to insecticide residues when foraging on weedy flowers in turfgrass systems. Deterrent practices may mitigate this risk by reducing pollinator visits; however, their effectiveness in limiting contact exposure of pollinators has not been thoroughly evaluated. Two trials were conducted using a randomized complete block design with three temporal blocks to assess the effectiveness of deterrent practices in preventing contact exposure of actively trapped honey bees (Apis mellifera) and passively trapped insects to fluorescent powder-treated white clover (Trifolium repens L.) inflorescences in turfgrass. Deterrent treatments included mowing the same morning before fluorescent powder application, spraying with a premix of 2,4-D, MCPP, and dicamba two d before powder treatment, or no deterrent before powder application. Fluorescent powder was extracted from 1,440 honey bee specimens collected by active trapping at 4 and 28 hours after treatment. Mowing and synthetic auxin herbicides pre-treatment reduced the number of fluorescent powder-exposed honey bees by at least 75% and 93%, respectively. Among exposed honey bees, mowing and herbicide treatments reduced powder concentration by at least 75% and 90%, respectively. Honey bee visitation was positively correlated with T. repens inflorescence density, explaining 81% of visitation variability. Mowing transiently decreased T. repens floral density by 85%, but recovered by 7 d, while herbicides resulted in complete loss of floral resources by 7 d. Blue vane traps captured 1,117 bees from 23 species, over 96% of which were native, while yellow sticky cards collected 384 insects from the Lepidoptera, Diptera, and Coleoptera orders. Despite differences in honey bee exposure, deterrent treatments did not affect the exposure of passively trapped pollinators to fluorescent powder, likely due to strong visual attraction of traps. Results suggest that mowing and synthetic auxin herbicides effectively deter honey bees from T. repens inflorescences, reducing their exposure risk.

Wide diversity in plant adaptive traits, such as seed size and dormancy, is generally linked to the rapid spread, invasiveness and adaptative potential of a weed species. Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] is a significant weed species in winter crops such as wheat (Triticum aestivum L.) and summer crops such as corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and peanut (Arachis hypogaea L.) in Alabama. In this study, diversity in seed morpho-physiological traits–such as seed length, awn length, seedling length, 100-seed weight, and seed dormancy was assessed in 65 L. multiflorum ssp. multiflorum populations collected from Alabama in 2023. Significant diversity was observed among the populations for 100-seed weight (61.8-295.8 mg), seed length (3.5-6.43 mm), awn length (0-7 mm), and seedling length (0.5-38.6 cm). Germination speed was significantly lower in the populations with high initial seed dormancy (>30%) compared to medium (15-30%) and low dormancy groups (<15%) at 0 and 3 months after harvesting. Additionally, the relationship between herbicide resistance status and seed morpho-physiological traits in these populations was explored. A significant positive association was observed between seed dormancy and the number of survivors following glyphosate (P < 0.01) and clethodim (P < 0.01) treatments. The observed diversity in morpho-physiological traits could be the reason of enhanced adaptability of L. multiflorum ssp. multiflorum, and its correlation with herbicide resistance indicates directional selection or co-existence of specific seed morpho-physiological traits with herbicide resistance under the repeated use of similar modes of action.

To address the complexity and excessive reliance on expert experience in tuning fuzzy Proportional-Integral-Derivative (PID) controller parameters, this study proposes a variable-rate spraying control system that integrates an improved Beetle Antennae Search (IBAS) algorithm with fuzzy PID control. To evaluate the feasibility of the system, a mathematical transfer function of the variable-rate spraying system was constructed, and a flow control simulation platform was established for simulation analysis. To overcome the limitations of conventional BAS, which is prone to premature convergence and limited search precision, the IBAS algorithm was developed. The improvements include a hybrid disturbance strategy to enhance individual search capability and a simulated annealing mechanism to prevent the algorithm from being trapped in local optima. Using the IBAS algorithm, the proportional and quantization factors of the fuzzy PID controller were optimized offline to obtain the optimal parameters. The IBAS-fuzzy PID controller was then compared in simulation with conventional PID, fuzzy PID, and BAS-optimized fuzzy PID controllers. The simulation results demonstrated that the IBAS-fuzzy PID algorithm achieved higher flow control accuracy than existing methods. To further validate the effectiveness of the improved algorithm under practical conditions, field experiments were conducted. The results indicated that the IBAS-optimized fuzzy PID controller outperformed the three other control methods in terms of flow control accuracy. Overall, both simulation and field results confirm that the proposed IBAS algorithm for fuzzy PID parameter optimization significantly enhances response speed, control precision, and overshoot reduction, providing a novel approach and potential application for variable-rate spraying technology.