Chemotaxonomy of the Cotton Leaf-Roller (Lepidoptera: Pyralidae) in Japan with Special Reference to Differences in Sex Pheromones

AbstractSynthetic sex pheromones released in a loblolly pine, Pinus taeda L. (Pinaceae), seed orchard interfered with the ability of male coneworm moths, Dioryctria Zeller spp. (Lepidoptera: Pyralidae), to locate traps baited with sex pheromones or live females. Pherocon 1C® traps baited with synthetic pheromones or live conspecific females were hung near the center of two 1.2-ha circular plots during emergence of Dioryctria amatella (Hulst), Dioryctria disclusa (Heinrich), and Dioryctria merkeli (Mutuura and Munroe). In a paired design, trap catches for the mating-disruption treatment with synthetic pheromone dispensers consisting of three polyvinyl chloride rods placed in every tree were compared with the control treatment. Treatments were alternated at intervals of 2–3 d. Trap catches of D. amatella were reduced by 91% when plots were treated with 2.5 g/ha of Z-11-hexadencenyl acetate. Catches were reduced by 99.5% for D. disclusa and by 97% for D. merkeli when plots were treated with 12.5 g/ha of Z-9-tetradecenyl acetate, whereas catches of D. amatella were unaffected by this mating-disruption treatment. Daily disappearance of Z-9-tetradecenyl acetate from the dispensers averaged 0.46 g/ha or less. Manually placing dispensers on nylon lines in the tops of trees was an effective method for releasing synthetic Dioryctria pheromones in the orchard. These data suggest it may be feasible to prevent mating of Dioryctria spp. in pine seed orchards by using synthetic pheromones for mating disruption, but large-scale tests will be required to demonstrate cone protection.

Download Full-text

Efficacy of Beauveria bassiana against the cotton leaf roller, Haritalodes (Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) under laboratory conditions.

Journal of Applied Biosciences ◽

10.35759/jabs.157.10 ◽

2021 ◽

Vol 157 ◽

pp. 16254-16266

Author(s):

Dannon H. Fabrice ◽

Douro Kpindou O. Kobi ◽

Toffa Mehinto Joelle ◽

Zantchedji D. M. Désiré ◽

Zinsou A. Valerien ◽

...

Keyword(s):

Beauveria Bassiana ◽

Field Experiments ◽

Good Alternative ◽

Lethal Concentration ◽

High Yield ◽

Cotton Leaf ◽

Plant Laboratory ◽

Leaf Roller ◽

Synthetic Pesticides ◽

Environmentally Friendly Method

Objective: The leaf-roller caterpillar Haritalodes (=Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) induces high yield losses by damaging cotton leaves and reducing the photosynthetic activity of the plant. Laboratory bioassays were carried to evaluate the effect of Beauveria bassiana on the survival of H. derogata larvae. Methodology and results: In the first trial, screening of thirteen B. bassiana isolates was performed on third larval instars at 107 conidia.mL-1 . In the second trial, effects of five concentrations (105 to 109 conidia.mL-1 ) of the three best isolates of the fungus were tested. Conidia suspension was applied on each larva topically. Germination rates of conidia used varied between 90.2% to 95.7%, 24 hours after incubation. Five isolates were found to be the most promising namely Bb116, Bb3, Bb11, Bb6 and Bb115. In the second bioassay, caterpillar mortality increased with fungal concentration. Lethal Concentration (LC50) was estimated to 1.18x1015 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 9 days after inoculation for Bb3, Bb11 and Bb115, respectively. Conclusion and application of results: The use of B. bassiana as a biopesticide against H. derogata could be a good alternative method to control the pest. It is an environmentally friendly method with less side effects compared to the application of synthetic pesticides on cotton. This method could be tested in future station and field experiments. Keywords: Cotton, Integrated pest management, Haritalodes (=Syllepte) derogata, Beauveria bassiana, Lethal Concentration.

Download Full-text