| |
|
|
|
| Author(s): | Lacey L.A., Unruh T.R. |
| Year: | 1998 |
| Title: | Entomopathogenic nematodes for control of codling moth, Cydia pomonella (Lepidoptera: Tortricidae): Effect of nematode species, concentration, temperature, and humidity |
| Citation: | Biological Control. 13: 190-197. . |
Abstract:
The susceptibility of codling moth diapausing larvae to three entomopathogenic nematode species was assessed in the laboratory using a bioassay system that employed cocooned larvae within cardboard strips. The LC50 values for Steinernema carpocapsae, S. riobrave, and Heterorhabditis bacteriophora were 4.7,4.8, and 6.0 infective juveniles/cm2, respectively. When a discriminating concentration of 10 infective juveniles/cm2 of each of the three nematode species was evaluated at 15,20,25, and 30oC, S. carpocapsae was the most effective nematode with mortalities ranging from 66 to 90%. Mortalities produced by S. riobrave and H. bacteriophora at the four temperatures were 2-94 and 25-69%, respectively. Studies were also conducted to test infectivity at 10,35, and 40oC. No mortality was produced by any of the nematode species at 10oC. S. riobrave was the most infective nematode at 35oC producing 68% mortality which was more than twice that observed for S. carpocapsae or H. bacteriophora. Codling moth larvae treated with 10 infective juveniles/cm2 of S. carpocapsae and kept in 95+% RH at 25oC for 0-24 h followed by incubation at 25-35% RH indicated that more than 3 h in high humidity was needed to attain 50% mortality. Trials of S. carpocapsae, S. riobrave, and H. bacteriophora at 50 infective juveniles/cm2 against cocooned larvae on pear and apple logs resulted in reductions of codling moth adult emergence of 83, 31, and 43%, respectively, relative to control emergence. Trials of the three entomopathogenic nematodes at 50 infective juveniles/cm2 against cocooned larvae in leaf litter resulted in 99 (S. carpocapsae), 80 (S. riobrave), and 83% (H. bacteriophora) mortality, respectively. Our results indicate good potential of entomopathogenic nematodes, especially S. carpocapsae, for codling moth control under a variety of environmental conditions |
|
|
|
|
|
|
|
|
