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Larvicidal effects of Chinaberry (Melia azederach) powder on Anopheles arabiensis in Ethiopia.

Trudel RE, Bomblies A - Parasit Vectors (2011)

Bottom Line: Chinaberry (Melia azederach) extracts have been shown to be effective growth-inhibiting larvicides against several insects.This experimental procedure was replicated three times.The Chinaberry had a highly statistically significant larvicidal effect at all treatment levels (χ2 = 184, 184, and 155 for 5 g m(-2), 10 g m(-2) and 20 g m(-2), respectively; p < 0.0001 in all cases).

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Vermont, Department of Civil and Environmental Engineering, Burlington, VT 05405, USA.

ABSTRACT

Background: Synthetic insecticides are employed in the widely-used currently favored malaria control techniques involving indoor residual spraying and treated bednets. These methods have repeatedly proven to be highly effective at reducing malaria incidence and prevalence. However, rapidly emerging mosquito resistance to the chemicals and logistical problems in transporting supplies to remote locations threaten the long-term sustainability of these techniques. Chinaberry (Melia azederach) extracts have been shown to be effective growth-inhibiting larvicides against several insects. Because several active chemicals in the trees' seeds have insecticidal properties, the emergence of resistance is unlikely. Here, we investigate the feasibility of Chinaberry as a locally available, low-cost sustainable insecticide that can aid in controlling malaria. Chinaberry fruits were collected from Asendabo, Ethiopia. The seeds were removed from the fruits, dried and crushed into a powder. From developmental habitats in the same village, Anopheles arabiensis larvae were collected and placed into laboratory containers. Chinaberry seed powder was added to the larval containers at three treatment levels: 5 g m(-2), 10 g m(-2) and 20 g m(-2), with 100 individual larvae in each treatment level and a control. The containers were monitored daily and larvae, pupae and adult mosquitoes were counted. This experimental procedure was replicated three times.

Results: Chinaberry seed powder caused an inhibition of emergence of 93% at the 5 g m(-2) treatment level, and 100% inhibition of emergence at the two higher treatment levels. The Chinaberry had a highly statistically significant larvicidal effect at all treatment levels (χ2 = 184, 184, and 155 for 5 g m(-2), 10 g m(-2) and 20 g m(-2), respectively; p < 0.0001 in all cases). In addition, estimates suggest that sufficient Chinaberry seed exists in Asendabo to treat developmental habitat for the duration of the rainy season and support a field trial.

Conclusions: Chinaberry seed is a very potent growth-inhibiting larvicide against the major African malaria vector An. arabiensis. The seed could provide a sustainable additional malaria vector control tool that can be used where the tree is abundant and where An. arabiensis is a dominant vector. Based on these results, a future village-scale field trial using the technique is warranted.

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A Chinaberry (Melia azederach) tree in Asendabo. A small amount of fruit was found in this particular tree, but fruiting yields were seen to vary greatly among trees.
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Figure 1: A Chinaberry (Melia azederach) tree in Asendabo. A small amount of fruit was found in this particular tree, but fruiting yields were seen to vary greatly among trees.

Mentions: The Chinaberry seeds collected for this experiment grew in abundance throughout Asendabo. A survey of the village was conducted in order to gauge the estimated yearly fruit yield of all the Chinaberry trees in the village. 434 Chinaberry trees were counted in Asendabo, a village with an area of 2 × 106 m2. This was observed to be a typical tree density in the Jimma region. The trees were observed to bear fruit during the rainy season, with abundant ripe fruit during July 2010, when the study was carried out. The local residents generally ignore the fruit, letting it fall to the ground, unused. The seeds are left to decompose in the environment. Dried seeds are also occasionally used to make jewelry. Villagers burn the tree's leaves to repel mosquitoes, and they brew a tea from the leaves to treat the symptoms of malaria. An example of a medium-sized Chinaberry tree in Asendabo is shown in Figure 1.


Larvicidal effects of Chinaberry (Melia azederach) powder on Anopheles arabiensis in Ethiopia.

Trudel RE, Bomblies A - Parasit Vectors (2011)

A Chinaberry (Melia azederach) tree in Asendabo. A small amount of fruit was found in this particular tree, but fruiting yields were seen to vary greatly among trees.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3101649&req=5

Figure 1: A Chinaberry (Melia azederach) tree in Asendabo. A small amount of fruit was found in this particular tree, but fruiting yields were seen to vary greatly among trees.
Mentions: The Chinaberry seeds collected for this experiment grew in abundance throughout Asendabo. A survey of the village was conducted in order to gauge the estimated yearly fruit yield of all the Chinaberry trees in the village. 434 Chinaberry trees were counted in Asendabo, a village with an area of 2 × 106 m2. This was observed to be a typical tree density in the Jimma region. The trees were observed to bear fruit during the rainy season, with abundant ripe fruit during July 2010, when the study was carried out. The local residents generally ignore the fruit, letting it fall to the ground, unused. The seeds are left to decompose in the environment. Dried seeds are also occasionally used to make jewelry. Villagers burn the tree's leaves to repel mosquitoes, and they brew a tea from the leaves to treat the symptoms of malaria. An example of a medium-sized Chinaberry tree in Asendabo is shown in Figure 1.

Bottom Line: Chinaberry (Melia azederach) extracts have been shown to be effective growth-inhibiting larvicides against several insects.This experimental procedure was replicated three times.The Chinaberry had a highly statistically significant larvicidal effect at all treatment levels (χ2 = 184, 184, and 155 for 5 g m(-2), 10 g m(-2) and 20 g m(-2), respectively; p < 0.0001 in all cases).

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Vermont, Department of Civil and Environmental Engineering, Burlington, VT 05405, USA.

ABSTRACT

Background: Synthetic insecticides are employed in the widely-used currently favored malaria control techniques involving indoor residual spraying and treated bednets. These methods have repeatedly proven to be highly effective at reducing malaria incidence and prevalence. However, rapidly emerging mosquito resistance to the chemicals and logistical problems in transporting supplies to remote locations threaten the long-term sustainability of these techniques. Chinaberry (Melia azederach) extracts have been shown to be effective growth-inhibiting larvicides against several insects. Because several active chemicals in the trees' seeds have insecticidal properties, the emergence of resistance is unlikely. Here, we investigate the feasibility of Chinaberry as a locally available, low-cost sustainable insecticide that can aid in controlling malaria. Chinaberry fruits were collected from Asendabo, Ethiopia. The seeds were removed from the fruits, dried and crushed into a powder. From developmental habitats in the same village, Anopheles arabiensis larvae were collected and placed into laboratory containers. Chinaberry seed powder was added to the larval containers at three treatment levels: 5 g m(-2), 10 g m(-2) and 20 g m(-2), with 100 individual larvae in each treatment level and a control. The containers were monitored daily and larvae, pupae and adult mosquitoes were counted. This experimental procedure was replicated three times.

Results: Chinaberry seed powder caused an inhibition of emergence of 93% at the 5 g m(-2) treatment level, and 100% inhibition of emergence at the two higher treatment levels. The Chinaberry had a highly statistically significant larvicidal effect at all treatment levels (χ2 = 184, 184, and 155 for 5 g m(-2), 10 g m(-2) and 20 g m(-2), respectively; p < 0.0001 in all cases). In addition, estimates suggest that sufficient Chinaberry seed exists in Asendabo to treat developmental habitat for the duration of the rainy season and support a field trial.

Conclusions: Chinaberry seed is a very potent growth-inhibiting larvicide against the major African malaria vector An. arabiensis. The seed could provide a sustainable additional malaria vector control tool that can be used where the tree is abundant and where An. arabiensis is a dominant vector. Based on these results, a future village-scale field trial using the technique is warranted.

Show MeSH
Related in: MedlinePlus