Advances in Phytochemistry, Textile and Renewable Energy Research for
Industrial Growth – Nzila et al. (Eds)
© 2022 Copyright the Author(s), ISBN: 978-1-032-11871-0
Open Access: www.taylorfrancis.com, CC BY-NC-ND 4.0 license
Chemical composition and insecticidal activity of Pinus caribaea Morelet
var. hondurensis needles against Sitophilus zeamais Motschulsky and
Callosobruchus maculatus Fabricius
John Mary Kirima
Department of Chemistry, Faculty of Science, Kyambogo University, Kampala, Uganda
Environmental Quality Management and Consultancy Department, Nkerebwe New Hope, Kampala, Uganda
Timothy Omara ∗
Africa Center of Excellence II in Phytochemicals, Textiles and Renewable Energy (ACE II PTRE), Moi University,
Eldoret, Kenya
Department of Chemistry and Biochemistry, School of Sciences and Aerospace Studies, Moi University,
Eldoret, Kenya
Department of Quality Control and Quality Assurance, Product Development Directory, AgroWays Uganda Limited,
Jinja, Uganda
ABSTRACT: Plant allelochemicals from essential oils have recently received considerable attention in pharmaceutical, cosmetic and agricultural sectors due to their biodegradability and low toxicity. This study analyzed
the chemical composition and bioinsecticidal activity of essential oils of Pinus caribaea Morelet var. hondurensis
needles. Thirty-nine (39) organic compounds were identified using gas chromatography/mass chromatography
and gas chromatography, and the most abundant components were limonene (38.6%), α-pinene (27.6%), borneol (6.7%) and myrcene (3.5%). The chemical composition of the needles was dominated by monoterpene
hydrocarbons (77.2%) followed by oxygenated monoterpenes (12.0%), sesquiterpene hydrocarbons (4.7%)
and then lastly oxygenated sesquiterpenes (1.7%). In fumigant toxicity, 100% mortality was recorded at
10 µL/ml for bean weevils after 2 hours of exposure whereas the same concentration caused 100% mortality of maize weevils after 5 hours of exposure. In repellency bioassay using aliquots of acetonic essential
oils, 100% repellence was recorded in bean weevils after 60 minutes of exposure while the same concentration (8 µL/ml) gave 100% repellence activity in maize weevils after 150 minutes. The essential oils showed
higher insecticidal activity against bean weevils than maize weevils. Based on the results of this study, pine
needles could be a suitable source of green insecticides for control of maize and bean weevils in stored food
products.
1 INTRODUCTION
Pests have been the worst enemy of man since
time immemorial. Maize weevils (Sitophilus zeamais
Motschulsky, 1855) and bean weevils (Callosobruchus
maculatus Fabricius) are some of the most destructive pests of stored food crops worldwide (Liao et
al., 2016). They cause extensive quantitative loss,
deterioration in food quality, seed viability, promote
secondary pest and fungal infestations that further initiate the development of mycotoxins (Omara et al.,
2020). Currently, their control relies heavily on synthetic insecticides which present problems such as
environmental pollution, pest resurgence (resistance)
and effects on non-target organisms in addition to
∗ Corresponding author
direct toxicity to the users (Jagadeesan, Nayak, Pavic,
Chandra, & Collins, 2015; Thompson & Reddy, 2016).
Thus, the current efforts are directed towards the development of novel biofumigants for the management of
stored product pests that are readily available, ecofriendly, effective and do not compromise food quality
(Gerwick & Sparks, 2014). A feasible alternative has
been to use plant products such as essential oils, ashes
and extracts (Gaire, Scharf, & Gondhalekar, 2019;
Omara et al., 2018).
Plant products are known for their properties of
low residue formation, high selectivity, and difficulty
to generate cross-resistance by insects (Isman, 2016).
This is mainly attributable to their complex constituents and different modes of action against pests
(Athanassiou, Hasan, Phillips, Aikins, & Throne,
2015). Over 2,000 plants have been reported to possess
162
DOI 10.1201/9781003221968-22
Industrial Growth – Nzila et al. (Eds)
© 2022 Copyright the Author(s), ISBN: 978-1-032-11871-0
Open Access: www.taylorfrancis.com, CC BY-NC-ND 4.0 license
Chemical composition and insecticidal activity of Pinus caribaea Morelet
var. hondurensis needles against Sitophilus zeamais Motschulsky and
Callosobruchus maculatus Fabricius
John Mary Kirima
Department of Chemistry, Faculty of Science, Kyambogo University, Kampala, Uganda
Environmental Quality Management and Consultancy Department, Nkerebwe New Hope, Kampala, Uganda
Timothy Omara ∗
Africa Center of Excellence II in Phytochemicals, Textiles and Renewable Energy (ACE II PTRE), Moi University,
Eldoret, Kenya
Department of Chemistry and Biochemistry, School of Sciences and Aerospace Studies, Moi University,
Eldoret, Kenya
Department of Quality Control and Quality Assurance, Product Development Directory, AgroWays Uganda Limited,
Jinja, Uganda
ABSTRACT: Plant allelochemicals from essential oils have recently received considerable attention in pharmaceutical, cosmetic and agricultural sectors due to their biodegradability and low toxicity. This study analyzed
the chemical composition and bioinsecticidal activity of essential oils of Pinus caribaea Morelet var. hondurensis
needles. Thirty-nine (39) organic compounds were identified using gas chromatography/mass chromatography
and gas chromatography, and the most abundant components were limonene (38.6%), α-pinene (27.6%), borneol (6.7%) and myrcene (3.5%). The chemical composition of the needles was dominated by monoterpene
hydrocarbons (77.2%) followed by oxygenated monoterpenes (12.0%), sesquiterpene hydrocarbons (4.7%)
and then lastly oxygenated sesquiterpenes (1.7%). In fumigant toxicity, 100% mortality was recorded at
10 µL/ml for bean weevils after 2 hours of exposure whereas the same concentration caused 100% mortality of maize weevils after 5 hours of exposure. In repellency bioassay using aliquots of acetonic essential
oils, 100% repellence was recorded in bean weevils after 60 minutes of exposure while the same concentration (8 µL/ml) gave 100% repellence activity in maize weevils after 150 minutes. The essential oils showed
higher insecticidal activity against bean weevils than maize weevils. Based on the results of this study, pine
needles could be a suitable source of green insecticides for control of maize and bean weevils in stored food
products.
1 INTRODUCTION
Pests have been the worst enemy of man since
time immemorial. Maize weevils (Sitophilus zeamais
Motschulsky, 1855) and bean weevils (Callosobruchus
maculatus Fabricius) are some of the most destructive pests of stored food crops worldwide (Liao et
al., 2016). They cause extensive quantitative loss,
deterioration in food quality, seed viability, promote
secondary pest and fungal infestations that further initiate the development of mycotoxins (Omara et al.,
2020). Currently, their control relies heavily on synthetic insecticides which present problems such as
environmental pollution, pest resurgence (resistance)
and effects on non-target organisms in addition to
∗ Corresponding author
direct toxicity to the users (Jagadeesan, Nayak, Pavic,
Chandra, & Collins, 2015; Thompson & Reddy, 2016).
Thus, the current efforts are directed towards the development of novel biofumigants for the management of
stored product pests that are readily available, ecofriendly, effective and do not compromise food quality
(Gerwick & Sparks, 2014). A feasible alternative has
been to use plant products such as essential oils, ashes
and extracts (Gaire, Scharf, & Gondhalekar, 2019;
Omara et al., 2018).
Plant products are known for their properties of
low residue formation, high selectivity, and difficulty
to generate cross-resistance by insects (Isman, 2016).
This is mainly attributable to their complex constituents and different modes of action against pests
(Athanassiou, Hasan, Phillips, Aikins, & Throne,
2015). Over 2,000 plants have been reported to possess
162
DOI 10.1201/9781003221968-22