Ozonation of Lima Bean (Phaseolus Lunatus L.): Control of Zabrotes Subfasciatus (Boheman, 1833) (Coleoptera: Chrysomelidae: Bruchinae) and Maintenance of Grain Quality

ABSTRACT

The objectives of this study were to evaluate the toxicity of ozone on Zabrotes subfasciatus (Boheman, 1833) in lima bean seeds, determine the instantaneous population growth rate (r_i) of these insects exposed to lethal and sublethal ozone doses, and evaluate their effects on the physical and physiological characteristics of lima beans. Toxicity was determined by using estimates of lethal doses (mg/g) for 50% and 95% of adult insects (LD₅₀ and LD₉₅) at the top and bottom of the fumigation chamber. We found that LD₉₅ values were 121.75 and 87.79 mg/g when the insects were distributed at the top and bottom of the chamber, respectively. The r_i values decreased from 0.077 to 0.002 when the seeds were exposed to ozone, while they increased from 0.07 to 0.08 when the seeds were exposed to oxygen. The water content of the seeds decreased from 11.2% b.u to 10.38% b.u. when the ozone dose increased. The germination percentage increased from 67% to 93% when the ozone dose was increased. Conductivity decreased from 51.88 μS cm⁻¹ g⁻¹ to 32.47 μS cm⁻¹ g⁻¹ when the ozone dose increased. The apparent specific mass increased when the ozone dose increased from 732.44 m⁻³ to 738.51 m⁻³. Ozone is toxic to Z. subfasciatus and affects its instantaneous growth rate; however, it does not affect grain quality. Therefore, ozone has the potential to be used to control Z. subfasciatus in stored grains.

KEYWORDS:

• Ozone
• toxicity
• stored grain pests
• fumigation
• population growth

Acknowledgments

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 00. To the Federal Institute of Education, Science and Technology of Maranhão (IFMA) Campus Codó, for all the structure and support made available for carrying out the experiment. To Gustavo Yves Rodrigues Ramos for his help with the work done at the Codó Campus.

Disclosure statement

The manuscript does not present any kind of conflict of interest.

Author contributions

Silva, YNM, Silva, PRR, França, SM and Silva, GN developed all stages of the manuscript production; Barbosa, DRS contributed with statistical analysis; Silva, YM and Brito, RC helped in the implementation of the bioassays.

Additional information

Funding

This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil CAPES [Finance Code 00].