| Entomopathogenic nematodes are an important biocontrol factor. But there are some factors that limited the commercial application of entomopathogenic nematodes, such as mass production of nematodes at a lower cost and a higher efficiency, storage time. The method of mass production with lower cost and higher efficiency is screened in this study. The calcium alginate granule formulation is developed to find a better store method of the nematodes. The results are as follows:1. Steinernema carpocapsae HB310 in vivo was reproduced by Galleria mellonella larvae and Tenebrio molitor larvae. The results showed that G. mellonella had a higher efficiency than T. molitor as the host. After 19 days, total nematode yield from G. mellonella larvae was 1.23×106IJs/g. Total nematode yield from T. molitor larvae was 4.96×105IJs/g. After hyperthermia treatment, the nematode yield from T. molitor larvae was much more than G. mellonella, but the cost of T. molitor was lower than that of G. mellonella, so T. molitor was much more suitable as host for reproducing nematodes.2. Entomopathogenic nematodes were reproduced by using solid culture mediums. Two solid culture mediums A and B were chosen to artificially propagate S. carpocapsae HB310, S. carpocapsae ALL, H. bacteriophora H06 and H. bacteriophora LN2 by related references. The results showed that propagation efficiencies and multiplication cycles of these two solid culture mediums were similar under the same inoculation of bacteria and nematodes. The yield of S. carpocapsae HB310 reached highest on 10 th day（0.86×104 IJs/g） and 20 th day（1.40×105 IJs/g） on the solid culture B and A respectively. The yield of S. carpocapsae ALL reached highest on 10 （th） day（4.19×105 IJs/g） and 20 th day（1.10×105 IJs/g） on the solid medium A and B respectively. The yield of nematodes H. bacteriophora H06 reached highest on 20th day both on the solid medium A（9.04×104 IJs/g） and B（2.42×105 IJs/g）. The yield of H. bacteriophora LN2 reached highest on 30th day both on the solid medium A（1.93×105 IJs/g） and B（1.01×105 IJs/g）. Another solid culture medium C was studied on the bases of the cost and accessibility of the material. The result indicated that the medium C was the best with the highest yield on 8th day（4.00×104 IJs/g）and lowest cost（4.25￥/ 1.00×106 IJs/g S. carpocapsae HB310）. The result of optimizing culture conditions were: 2.26×107cfu/flask bacteria inoculate volume, 1×103 IJs /g nematodes inoculate volume, 12 d culturing time.3. A series of studies were conducted based on calcium alginate granules of S. carpocapsae HB310. At first we found that the dormancy nematodes could easily induced in 18% glycerol. And then a calcium alginate granule was shaped when mixed glycerol, formaldehyde, sodium alginate and potassium sorbate together. The nematode calcium alginate granules were an ellipse colloid granule in 2-5mm diameter. The dormancy nematodes were enclosed in a capsule.Calcium alginate granules can be stored for 4 months at 16℃, 100% humidity. After dissolved by 0.5% citric acid, the nematode survival rate was up 75%, and the infection rate and fatality rate of nematodes against G. mellonella larvae were 19.3% and 92%. The result shows that S. carpocapsae HB310 can survive as calcium alginate granules for long time and keep a high infection rate. |
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