| Biological control is an important means of area-wide integrated pest management(AW-IPM),and natural enemies eating pests is a key technology of biological control.Artificially distributing natural enemies to protect crops requires a lot of manpower,while maintaining a long period of labor in a humid or high temperature environment can lead to human discomfort and fatigue.However,using mechanical device instead of artificial can reduce the delivery time and benefit the health and safety of the workers.At present,foreign countries have developed a variety of equipment covering the ground and aviation,and carried out large-scale field trials of distributing natural enemies.But China is still the main manual delivery and it lacks appropriate equipment and assessment methods of the effect of delivery.In view of the above problems,combined of the development of China's agricultural production and the characteristics of pests and diseases,based on the physical characteristics of natural enemies and the development of related equipment in developed countries,this paper designed a set of distribution devices for Harmonia axyridis.Based on vibration theory and image processing technology,the dynamic characteristics of the device and the distribution effect are taken into study.The main research work includes the following five aspects:(1)A set of mechanized distribution prototype for Harmonia axyridis was developed.At present there is no commercialization of natural enemies distribution mechanical device in China.In view of this situation,this paper has developed a mechanized distribution device can work by single in the field integrated of the power system,Harmonia axyridis amount adjustment mechanism,the control system and the rack.The device has a net weight of 11.5 kg and a maximum horizontal distance of 5 m.Aiming at area-restricted search behavior for the Harmonia axyridis,the device has two switchable modes: continuous delivery,cycle intermittent delivery.(2)Parameter calculation and experimental study of Harmonia axyridis amount adjustment mechanism.Based on the measured physical properties of Harmonia axyridis,the specific structural parameters of the adjusting mechanism were determined,and the relationship model among the number of delivery,the rotating speed of the small impeller and the time of delivery was established,and the accuracy of the model was verified by experiments.(3)Vibration experiment and vibration reduction design of initial prototype.The vibration test of the preliminary prototype is carried out in two working conditions.The damping device was designed based on first-order perturbation frequency of the experiment.The damper damping device based on the torque balance test result.The main vibration frequency is up to 71.82%~79.95% and 67.96%~89.23% respectively,the vibration acceleration level decreases 7.17 d B~9.41 dB and 6.63dB~8.79 dB respectively in the two conditions.(4)Study on counting methods of Harmonia axyridis based on MATLAB image processing technologyCombining MATLAB image processing technology with mobile phone camera function.The maximum cross-sectional area method is used to count the number of Harmonia axyridis in the specified area.The method is more suitable for the batch processing of the images than the watershed algorithm and the erode algorithm.(5)The prototype distribution trial in the field.By changing the outlet wind speed,the small impeller speed to carry on fixed-point delivery and the fixed-regional operation of the two strategies of the test,the following conclusions:(1)The concentration points of the two outlet winds are located in the middle and middle of the distribution zone;(2)Horizontal distribution has a 2m long gentle areas by fixed-regional delivery.(3)The results showed that there was no significant effect on the survival rate of Harmonia axyridis(sig = 0.983> 0.05);the speed of small impeller had a significant effect(sig<0.05)on the survival rate of Harmonia axyridis.(4)The adhesion rate of 10 g of Harmonia axyridis was 1.4% ~ 5.7%.In the field operation,the number of natural enemies should be increased. |
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