Spatio-temporal distribution of Anthonomus grandis grandis Boh. in tropical cotton fields

Authors: OLIVEIRA, ANDREA - University Of Brazil; DE ARAUJO, TAMIRIS - Universidade Federal De Sao Carlos; Showler, Allan; DE ARAUJO, ANA - University Of Brazil; ALMEIDA, IGOR - University Of Brazil; AGULAR, RENATA - University Of Brazil; MIRANDA, JOSE - Embrapa; FERNANDES, FLAVIO - Universidade Federal De Vicosa; BASTOS, CRISTINA - University Of Brazil

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2022
Publication Date: N/A
Citation: N/A
DOI: https://doi.org/10.1002/ps.6880

Interpretive Summary: Knowing the space-time distribution of pests is important for developing approaches to their management. The boll weevil is a deleterious cotton pest in the Western Hemisphere. The spread of boll weevils across cotton fields has been poorly understood. We assessed the dispersal pattern of adult weevils through cotton fields cultivated in a tropical area during dry and wet seasons using geostatistical approaches for infested reproductive structures, flower buds and bolls, and on numbers of adults. Climatic variables did not limit adult boll weevil populations, and both adult weevils and infested reproductive structures increased during each season. Using 33 and 36 variogram models for the dry and wet seasons, respectively, with the selection of 14 models for each season we determined that, in both seasons, samples were spatially dependent, confirming an aggregated distribution of boll weevil adults and infested reproductive structures. The distances over which the samples maintained spatial dependence varied from 2.3 to 44.1 m in the dry season and from 3.3 to 408.9 m in the wet season. Boll weevils started the infestation at field borders and the infested reproductive structures were greater than the adults regardless of cotton growth stage. Sampling for boll weevils in cotton fields should start at the field borders and focus on infested reproductive structures using a 6-8 m distance between samples. As cotton plants develop, sampling of reproductive structures should focus on the field as a whole using distances among the samples that vary from 8-305 m, 6-410 m, and 4-14 m when the plants are at the initial flowering, late flowering and open bolls stages, respectively.

Technical Abstract: Knowing the spatio-temporal distribution of pests is important for developing approaches to their management. The boll weevil, Anthonomus grandis grandis Boh., is a deleterious cotton, Gossypium hirsutum L., pest of the Western Hemisphere. The spread of boll weevils across cotton fields remains poorly understood. We assessed the dispersal pattern of adult weevils through cotton fields cultivated in a tropical area during dry and wet seasons using geostatistics for infested reproductive structures, flower buds and bolls, and on numbers of adults. Climatic variables did not limit adult boll weevil populations, and both adult weevils and infested reproductive structures increased during each season. Variogram analysis allowed the adjustment of 33 and 36 models for the dry and wet season, respectively, with the selection of 14 models for each season. In both seasons, samples were spatially dependent, confirming an aggregated distribution of boll weevil adults and infested reproductive structures. The distances over which the samples maintained spatial dependence varied from 2.3 to 44.1 m in the dry season and from 3.3 to 408.9 m in the wet season. Boll weevils started the infestation at field borders and the infested reproductive structures were greater than the adults regardless of cotton growth stage. Sampling for boll weevils in cotton fields should start at the field borders and focus on infested reproductive structures using a 6-8 m distance between samples. As cotton plants develop, sampling of reproductive structures should focus on the field as a whole using distances among the samples that vary from 8-305 m, 6-410 m, and 4-14 m when the plants are at the initial flowering, late flowering and open bolls stages, respectively.