Use of Photorhabdus as a biopesticide a- Cell suspension from Photorhabdus sp. against Galleria mellonella insect

Document Type : Original Article

Authors

1 Agricultural Microbiology Department, National Research Center, Cairo, Egypt

2 Nematology laboratory, phytopathology Department, National Research Center, Cairo, Egypt

Abstract

Integrated Pest Management (IPM) is today a widely accepted strategy for reducing overdependence
on chemical insecticides and to reduce their potentially negative environmental and economic effects.
Photorhabdus is a gram-negative enteric bacterium that is found in association with entomopathogenic
nematodes of the family Heterorhabditidae. The nematodes infect a variety of soil insect pests. Upon
entering an insect host, the nematode releases Photorhabdus spp. cells from its intestinal tract, and the
bacteria quickly establish a lethal septicemia. When grown in yeast salt broth, in the absence of the
nematodes, the bacteria produce a toxin protein that is lethal when fed to the hemolymph of several
insect species. Broth cultures of five isolates of Photorhabdus (A, B, C, D, E) were lethal to the
nymphs of Galleria mellonella when mixed different concentrations (5,10 and 20 ml) from suspension
bacterial cell with two kind of media (wheat bran and fine sand) as compared to broth alone (control).
Results obtained showed that, after one day the mortality reached 100 % on sand inoculated with 20 ml
cells suspension of the isolates A, C and D. A hyperbolic relationship was observed between different
isolates, type of media, doses and time intervals. These bacterial cells were also recovered from the
abdominal haemocoele indicating that bacterial symbionts do have a free-living existence and can enter
in the haemocoele in the absence of nematode vector.

Keywords

Files

Share

How to cite

Statistics