Occurrence and Abundance of Aphid Species in Coastal Region of Bangladesh

Abstract

Aphid samples were collected from bean and brinjal plants in the coastal region (Patuakhali, Barguna, Barishal, Pirojpur, Gopalgonj and Satkhira) of Bangladesh. The survey was conducted several times at the same locations to identify the species and assess the incidence and abundance of aphid species on bean and brinjal. Molecular identification was performed in the Insect Molecular Physiology Laboratory of Kyungpook National University, Korea, using mitochondrial cytochrome oxidase subunit I (mtCOI) sequences. Molecularly, two species (Aphis craccivora and Aphis gossypii) were identified by comparing their nucleotide sequences with other nucleotide sequences in the NCBI GenBank database, which formed different clades in the phylogenetic tree with distinct distances. Infestations of the brinjal aphid (Aphis gossypii) varied among localities. Survey findings indicated that Patuakhali was the most vulnerable location to A. gossypii (633.33), followed by Barishal (317.77), Pirojpur (317.17) and Barguna (306.66). The lowest number of A. gossypii (4.26) was recorded at Gopalgonj, followed by Satkhira (11.8), Barguna (22.33), Barishal, Pirojpur (24.44) and Patuakhali (82.55). The maximum occurrence of A. gossypii (173.33) was recorded across the surveyed locations in February, except at Patuakhali, where it occurred in March (633.33), and the lowest number of A. gossypii (4.26) per plant was recorded in May across all locations. Further survey investigation revealed that infestations of the bean aphid (Aphis craccivora) varied among localities. Survey findings indicated that Satkhira was the most vulnerable location to A. craccivora (1907.11), followed by Gopalgonj (1729), Pirojpur (1285) and Barishal (1142.77). The lowest number of A. craccivora (257.86) was recorded at Barguna, followed by Patuakhali (702.11). The maximum occurrence of A. craccivora (1729) was recorded across the surveyed locations in February, and the lowest number of A. craccivora (22.3) per plant was recorded in May across all locations. Moreover, the meteorological data clearly showed a negative correlation with increasing aphid populations on both bean and brinjal. Furthermore, aphid infestation on bean at every location was five- to ten-fold higher than on brinjal.