Assessment of insecticidal effectiveness of selected crude plant extracts on the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)
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Date
2017
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Publisher
Sokoine University of Agriculture
Abstract
Effects of Commiphora swynnertonii, Synadenium glaucescens and Allium sativum
ethanolic extracts on the tomato leaf miner, Tuta absoluta Meyrick were evaluated under
laboratory and screen house conditions. The threes life stages (eggs, second instar larvae
and adults) of the tomato leaf miner were involved in the experiment. All the life stages of
tomato leaf miner were treated topically with the plants extracts at (2%, 4% and 8%). The
mean percentage mortality of eggs, second instar larvae and adults were recorded daily for
5 days. Results indicated that, each plant extract caused significant mortality to larvae and
adults of T. absoluta after 5 days in comparison to the control. In laboratory, using the leaf
dipping technique, Commiphora showed the highest effects on T. absoluta second instar
larvae while Synadenium extract exhibited the least effect. The Commiphora ethanolic
extract was the only one that showed potential to be used as a control agent against eggs as
it led to 0% egg hatchability. Synadenium resulted in no mortality of T. absoluta eggs in
this trial as there was 96.6% hatchability. Leaf dipping against second instar and adult of
T. absoluta proved to be the most effective for all plants extracts at 30-100%.
Commiphora resulted in the highest second instar larval and adults’ mortality of 100%. In
the screen house Commiphora showed the high reduction of infestation for Tanya and Cal
J varieties. Treatment with this plants extracts resulted in the highest fruit yield and the
lowest yield loss compared to all the plant extracts. Commiphora swynnertonii extract is
recommended into integrated pest management strategies for the control of T. absoluta.
Description
M.SC. Dissertation
Keywords
Insecticidal effectiveness assessment, Tomato leaf miner, Tuta absoluta, Lepidoptera - Gelechiidae, Commiphora swynnertonii, Synadenium glaucescens, llium sativum ethanolic extracts