| Virulence of Carboxymethyl Cellulose formulation of H. bacteriophora and S. carpocapsae against Phthorimaea operculella |
| Paper ID : 1090-3IICE |
| Authors: |
|
Naser Eivazian Kary *1, Davoud Mohammadi2 1Dep. of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, Iran 2Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, IRAN |
| Abstract: |
| Entomopathogenic nematodes (EPNs) from families Heterorhabditidae and Steinernematidae have proven to be effective biological control agents. Here the effect of storage period on virulence of carboxymethyl cellulose (CMC) formulated infective juveniles (IJs) of H. bacteriophora and S. carpocapsae was tested at one month interval over 6 months. Virulence of both EPNs was evaluated as LC50 values on PTM 2nd instar larva. Potato tuber moth (PTM), Phthorimaea operculella is one of the most important pests of the plant family Solanaceae is specially known for being major pest of potato crops. The virulence was evaluated in 24-well plates lined with two filter papers. IJs were applied in 1 ml distilled water to the filter paper surface before the PTM individuals were added to the well. Untreated controls received only distilled water. Mortality was recorded daily for 7 days starting after 48 h. The experiment was conducted twice. The LC-values were calculated using probit analysis. Mortality data were corrected for mortality in the untreated controls and subjected to analysis of variance followed by Duncan's mean separation test. LC values for both EPNs had a good fit to the probit regression model. The analysis showed that LC50 of CMC formulated IJs of both studied EPNs weren’t affected by storage period. All recorded LC50 values had overlapped confidence intervals. In the case of H. bacteriophora recorded values of LC50 at one month interval were 117.09, 97.17, 112.91, 102.94, 114.10 and 123.14 IJs/L, these values were 74.65, 66.80, 73.19, 71.70, 76.02 and 68.83 IJs/L for S. carpocapsae. Although S. carpocapsae with ambusher foraging strategy appeared more virulent against PTM larvae but given the small size of the experimental arenas it is unlikely that recorded differences in virulence were related to the ambusher- or sit-and-wait strategy type foraging strategy of S. carpocapsae IJs that would have favored infection of the mobile larvae. Therefore it is proposed that further research should be conducted in greenhouse and field studies with the combination use of these valuable biocontrol elements. |
| Keywords: |
| Bioassay, Infective Juveniles, LC50, Virulence |
| Status : Paper Accepted (Poster Presentation) |
