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Evaluation of the water fern Azolla microphylla for mosquito population management in the rice‐land agro‐ecosystem of south India
Author(s) -
RAJENDRAN R.,
REUBEN R.
Publication year - 1991
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/j.1365-2915.1991.tb00556.x
Subject(s) - azolla , biology , culex tritaeniorhynchus , fern , population , biological pest control , paddy field , agronomy , botany , horticulture , veterinary medicine , japanese encephalitis , medicine , encephalitis , virus , demography , virology , sociology
. The floating water fern Azolla microphylla Kaulfess was evaluated as a biocontrol agent against mosquitoes breeding in rice fields in Tamil Nadu, South India. Anopheles subpictus Grassi, Culex pseudovishnui Colless and Culex tritaeniorhynchus Giles were the predominant species of mosquitoes, with peak densities of late instar larvae and pupae occurring during the second week after transplantation of rice seedlings of short‐term (c. 80 days from transplantation to harvest) or medium‐term (c. 95 days) varieties. Immature mosquito populations were reduced by mats of Azolla microphylla covering more than 80% of the water surface. However, since 80% coverage by Azolla was achieved only 13–14 days after rice transplantation, its usefulness for mosquito control was limited. Azolla may have a greater potential in an integrated control programme, or in areas where long‐term varieties of rice are predominantly grown.