Search

To study the antifungal effect and mechanism of linalool against Fusarium oxysporum FOX-1, the causative agent of ginger Fusarium wilt, the damaging effects of different concentrations of linalool on the mycelial growth, spore germination and cell membrane of F. oxysporum FOX-1, and its control effect on ginger Fusarium wilt were systemically investigated. The results showed that linalool could significantly inhibit the mycelial growth of F. oxysporum FOX-1 in a concentration-dependent manner, and the half maximal effective concentration (EC50) and the minimum inhibitory concentration (MICs) were 1.183 and 2 g/L, respectively. The spore concentration of F. oxysporum FOX-1 treated with linalool at MIC for 6 h was (1.43 ± 0.12) × 104 spores/mL, which was significantly lower than that of the control group ((5.79 ± 0.19) × 104 spores/mL) (P < 0.05), and the spore germination rate of F. oxysporum FOX-1 treated with linalool at MIC for 12 h was (5.83 ± 2.16)%, which was significantly lower than that of the control group ((95.12 ± 3.78)%) (P < 0.05). Treatment with linalool at 1/2 MIC and MIC damaged the integrity of the cell membrane, resulting in a significant increase in relative electrical conductivity and nucleic acid leakage in the mycelial suspension and malondialdehyde (MDA) content in the mycelium, and a significant decrease in ergosterol content, finally weakening the pathogenicity of the fungus. No lesions appeared on ginger pieces after treatment with linalool at MIC for 3 days. In conclusion, linalool affects the normal physiological function of F. oxysporum FOX-1 by inhibiting its spore germination and mycelial growth and destroying its cellular structure. This study provides a new direction for the effective control of Fusarium wilt.

The aim of this article was to discuss the modeling and control method of quadrotor unmanned aerial vehicle (UAV). In the process of modeling, mechanism modeling and experimental testing are combined, especially the motor and propeller are modeled in detail. Through the understanding of the body structure and flight principle of the quadrotor UAV, the Newton–Euler method is used to analyze the dynamics of the quadrotor UAV, and the mathematical model of the UAV is established under the small angle rotation. Process identifier (PID) is used to control it. First, the attitude angle of the model is controlled by PID, and based on this, the speed in each direction is controlled by PID. Then, the PID control of the four rotor aircraft with the center of gravity offset is simulated by MATLAB. The results show that the pitch angle and roll angle can be controlled by 5 degrees together without center of gravity deviation, and the PID can effectively control the control quantity and achieve the desired effect in a short time. Classical BP algorithm, classical GA-BP algorithm, and improved GA-BP algorithm were trained, respectively, with a total of 150 sets of training data, training function uses Levenberg-Marquardt (trainlm), and performance function uses mean squared error (MSE). In the background of the same noise, the improved GA-BP algorithm has the highest detection rate, classical GA-BP algorithm is the second, and classical BP algorithm is the worst. The simulation results show that the PID control law can effectively control the attitude angle and speed of the rotor UAV in the case of center of gravity deviation.

Live poultry markets (LPMs) are hot spots for avian influenza virus (AIV) amplification among poultry and dissemination to humans (1). Direct contact with live poultry is a major route of [...]