Stduies On Mass Rearing And Field Release Technology Of Harmonia Axyridis

Nowadays, it is a hot subject in the study of the relationships amang host plant, insect pests and natural enemies for biological control, it can provide us an theoretical guidance on how to use of artificial rearing natural enemies and field release control the insect pests by revealing their nutrition relation. Harmonia axyridis is a very important predative natural enemy which is fed on aphid, the status of the Harmonia axyridis in agricultural biological control is gradually rising and has been widely applied in the field because of the rise and development of green agriculture. In this paper, we sum up and optimize the Harmonia axyridis artificial rearing method based on the related data, build the Harmonia axyridis artificial rearing room, artificial rearing the Harmonia axyridis indoors, then release the Harmonia axyridis in the field for effective control of aphids.1Build Harmonia axyridis artificial rearing roomBuild the artificial rearing room before large-scale rearing Harmonia axyridis. Artificial rearing room conditions:Temperature25±5℃, humidity50%-70%, photoperiod L:D=16:8. The auther have been reared a large number of Harmonia axyridis in this rearing room successfully, it is proved that this artificial rearing room meet the requirements of rearing Harmonia axyridis.This artificial rearing room has applied for patent "one kind of Harmonia axyridis artificial rearing room" and has been published.2Harmonia axyridis artificial rearing in different densitiesThe auther carry out experiment in the Harmonia axyridis rearing room condition, the results showed that:The hatch rate of Harmonia axyridis between80%-90%; Larva survival rate and egg-adult rate increase with the density of egg mass, and the survival rate of2nd instar larva、3rd instar larva、pupation rate of4th instar larva、eclosion rate of pupae are between95%-100%, but the survival rate of1st instar larva are different under different rearing methods. When placed1st instar larva on the larva rearing box (45cmx35cmx10cm) directly, the survival rate of1st instar larva is only about14%; But increase to85%when placed1st instar larva in a small rearing box(Φ12cmx10cm) alone. The whole larva survival rate reach to70%-80%, egg-adult survival rate reach to60% -70%. The emergenced Harmonia axyridis adults are rearing on adult rearing cage (45cmx35cmx35cm). Under the rearing densities of50, the mortality on5th days、10th days、15th days、20th days were3.33%、4.00%、5.33%、6.67%; Under the rearing densities of100, the mortality rates were4.33%、5.33%、6.67%、9.33%; Under the rearing densities of150, the mortality rates were5.78%、7.56%、9.56%、13.11%; Under the rearing densities of200, the mortality rates were8.50%、10.33%、13.33%、17.17%; Under the rearing densities of250, the mortality rates were10.13%、12.13%、16.00%、21.20%. The mortality rate of Harmonia axyridis adult increased with rearinging densities and time. The total egg-laying number (114.33<200.67<311.67<438.67<541.00<643.00) of Harmonia axyridis adult increased with Harmonia axyridis adult density (one pair、two pairs、three pairs、four pairs、five pairs、six pairs) increased, but the egg-laying number per female adult in one day (16.34>14.33<14.84<15.67>15.46>15.31) were no significant difference, all about15.3The effect factor of Harmonia axyridis field releaseThe auther carry out experiment in the effect factor of Harmonia axyridis field release by released the reared Harmonia axyridis adult and4th instar larva into the tobacco fields. The results of experiment on Harmonia axyridis fed on Myzus persicae in laboratory conditions show that:The predacious number of4th instar larva(34.89<62.33<82.44<91.78<100.67) and adult (25.89<43.11<61.22<76.22<81.56) increased with the densities of Myzus persicae (40<70<100<140<180), and will eventually tend to stabilize (to the maximum); And when the amount of Myzus persicae (100) determined, the predacious number of4th instar larva (82.44>44.28>31.37>23.80>19.47) and adult (61.22>40.83>28.52>23.33>19.20) reduced with the densities of Harmonia axyridis (1、2、3、4、5individual) increase. Tobacco volatiles had a little influence to the predation of Harmonia axyridis4th instar larva (10.12<11.00) and adults (9.44<10.50), but was no significant difference.