LC and LD50 values of Bacillus thuringiensis Serovar japonensis strain buibui toxin to Oriental beetle and northern masked chafer larvae (Coleoptera: Scarabaeidae).
Bacillus thuringiensis serovar japonensis strain Buibui has the potential to be an important control agent for pest scarabs. Bioassays were designed to test B. t. japonensis against two of the major turf and ornamental scarab pests infesting turfgrasses and ornamentals and to serve as a basis for further tests against other scarab pests. LC and LD50 values of B. t. serovarjaponensis strain Buibui toxin and spores were determined by four different bioassays for the oriental beetle, Anomala orientalis (Waterhouse), and northern masked chafer, Cyclocephala borealis Arrow. Oriental beetle larvae were bioassayed in autoclaved and nonautoclaved soil from where they were collected (Kingston, RI [native]), in nonautoclaved soil from where the northern masked chafer larvae were collected (Groton, CT [foreign]), and per os. Northern masked chafer larvae were bioassayed in autoclaved and nonautoclaved soil from where they were collected (Groton, CT [native]), in nonautoclaved soil from where the oriental beetle larvae were collected (Kingston, RI [foreign]) and per os. LC50 values of 3.93 microg toxin/g autoclaved native soil, 1.80 microg toxin/g nonautoclaved native soil, and 0.42 microg toxin/g nonautoclaved foreign soil and an LD50 value of 0.41 microg per os were determined at 14 d forA. orientalis. LC50 values of 588.28 microg toxin/g autoclaved native soil, 155.10 microg toxin/g nonautoclaved native soil, 265.32 microg toxin/g nonautoclaved foreign soil, and LD50 of 5.21 microg per os were determined at 14 d (soils) and 10 d (per os) for C. borealis. There were significant differences in LC50 values for oriental beetles in autoclaved, nonautoclaved native soil and nonautoclaved foreign soil. There were significant differences in LCo values for northern masked chafers in autoclaved and nonautoclaved native soil. B. t. japonensis can be applied now for control of oriental beetles at rates that are economically competitive with synthetic chemicals. If we can determine the component of nonautoclaved soil that enhances the activity of toxin, it may be possible to lower the rates of toxin needed for control to more economical levels for more difficult to control species such as the northern masked chafer.
Mashtoly
Tamer A
TA
Plant Protection Department, Faculty of Agriculture, Ain Shams University, P.O. Box 68 Hadayek Shoubra, 11241 Cairo, Egypt.
El-Zemaity
Mohamed El-Said
Mel-S
Hussien
Mohamed I
MI
Alm
Steven R
SR
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D001427:Bacterial Toxins / Q000633:toxicity*; D001517:Coleoptera / Q000187:drug effects / Q000382:microbiology*; D007814:Larva / Q000382:microbiology*; D007928:Lethal Dose 50; D018402:Manduca / Q000187:drug effects; D010572:Pest Control, Biological; D012988:Soil Microbiology
D001427:Bacterial Toxins