Open AccessMicrobial larvicides for mosquito control: Impact of long lasting formulations of Bacillus thuringiensis var. israelensis and Bacillus sphaericus on non‐target organisms in western Kenya highlands
Author(s) -
Derua Yahya A.,
Kahindi Samuel C.,
Mosha Franklin W.,
Kweka Eliningaya J.,
Atieli Harrysone E.,
Wang Xiaoming,
Zhou Guofa,
Lee MingChieh,
Githeko Andrew K.,
Yan Guiyun
Publication year - 2018
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.4250
Subject(s) - bacillus sphaericus , bacillus thuringiensis , biology , habitat , mosquito control , ecology , larva , biological pest control , abundance (ecology) , species richness , pesticide , bacillales , toxicology , malaria , bacteria , genetics , bacillus subtilis , immunology
The microbial larvicides Bacillus thuringiensis var. israelensis and Bacillus sphaericus have been used extensively for mosquito control and have been found to be effective and safe to non‐target organisms cohabiting with mosquito larvae. Recently developed long lasting microbial larvicides ( LLML ), although evading the previous challenge of short duration of activity, increase the risk of persistence of toxins in the treated larval habitats. This study monitored the impact of LLML FourStar ® and LL 3 on non‐target organisms cohabiting with mosquito larvae in an operational study to control malaria vectors in western Kenya highlands. A total of 300 larval habitats were selected in three highland villages. The habitats were first monitored for 5 weeks to collect baseline data on non‐target organisms cohabiting with mosquito larvae and then randomized into two treatment arms (respective FourStar ® and LL 3) and one control arm. Non‐target organisms were sampled weekly for 5 months after treatment to assess the impact of LLML intervention. Before treatment, the mean density of all non‐target organisms combined in the control, LL 3 and FourStar ® treated habitats was 1.42, 1.39 and 1.49 individuals per habitat per sampling occasion, respectively. Following treatment, this density remained fairly unchanged for 21 weeks at which time it was 1.82, 2.11, and 2.05 for the respective control, LL 3 and FourStar ® treated habitats. Statistical analysis revealed that LL 3 and FourStar ® did not significantly alter abundance, richness or diversity of the 11 taxa studied, when comparing the intervention and control larval habitats. However, both FourStar ® and LL 3 significantly reduced the density of malaria vectors. In conclusion, one round of label rate application of FourStar ® or LL 3 in natural larval habitats did not alter richness, abundance or diversity of the monitored aquatic non‐target organisms cohabiting with mosquito larvae to an ecologically significant level.