Application of Biological Pesticides in Medicinal Plants

At present, the excessive application of traditional chemical pesticides, serious pesticide residue pollution and destruction of the ecological balance in China have become important factors affecting the quality and safety of medicinal material. Biological pesticides are rapidly developed due to their characteristics of high efficiency, low toxicity and residue. This study aimed to introduce the specific property of biological pesticides, review the classification of biological pesticides and their application in medicinal plants, analyze the problems in the production and utilization process of biological pesticides, and forecast the developmental prospect.

Effects of Biological Pesticides on Prevention and Treatment of Virus Diseases in Greenhouse Tomato in Autumn

To alleviate the damage of tomato virus diseases, reduce chemical pesticide consumption and residue, and prevent environmental pollution, forecasting, randomized block design and statistical analysis were adopted to conduct field efficacy tests for Lentinan ＋ Gibberellin-heteroauxin-brassinolide （GHB） and Ningnanmycin ＋ GHB. The results showed that when the virus diseases in greenhouse tomato were serious, 0.5% Lentinan AS 3 000 ml ＋ GHB WP 600 g and 8% Ningnanmycin AS 900 ml ＋ GHB WP 600 g per hectare were applied 4 times with an interval of 7 days, and the control effects on the 10th, 17th, 26th and 35th day were above 88%, 87%, 78% and 67%, respectively. The difference in control effect of the two biological pesticides was insignificant, while their control effects were all significantly better than that of moroxydine hydrochloride （CK） ＋ GHB. The obtained results indicated that Lentinan ＋ GHB and Ningnanmycin ＋ GHB were the ideal biological pesticides, which could be used not only for controlling tomato virus diseases, but also for realizing modern, pollution-free, green and organic agricultural production.

Control Efficiency of Four Biological Pesticides against Pieris rapae Linne and Their Impacts on Yield and Benefit of Chinese Cabbage

[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC （organic chemical pesticide） and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times： the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield （177 262.5 kg/hm2 ） and the income after deducting spraying cost （48 858.5 yuan/hm2 ） were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.

Experimental study on spraying performance of biological pesticides in aerial rotary cage nozzle

Aviation spraying is one of the most important methods for the treatment of forestry pests and diseases,which has a high operation efficiency and effectiveness.The combination of aviation spray and biological pesticides to reduce the impact of pesticide spray on environment has become an important development in the direction of agricultural aviation.In order to explore the effects of aviation spray parameters on particle size distribution and activity retention of biological pesticide droplets,a system of droplets size test and an activity retention rate test system of biological pesticides were constructed.The related experiments were conducted by changing the structural parameters of the rotary cage nozzle(the diameter of nozzle)and the technical parameters of the operation(rotary speed and flow rate).The results showed that the average relative width S of the droplets of the rotary cage nozzle was close to 1,and the droplet distribution was uniform.The influence factors on the particle size distribution of biological pesticide droplets were rotary speed,nozzle diameter,medium and flow rate in descending order.The rotary speed,nozzle diameter,and medium had a significant influence on droplet size distribution.The average activity retention rate of Bacillus thuringiensis was 88.83%,and the germination rate of Beauveria bassiana was 89.80%.The rotary speed had a significant effect on the activity retention rate of bacterial and fungal biological pesticides,and it was negatively correlated.The rotary speed was between 3000-5000 r/min,and the activity retention rate was higher.The research results can provide guidance for spraying biological pesticides in aerial plant protection operations with rotary cage nozzle.