Background: The whitefly (
Bemisia tabaci
Genn.) is a widely distributed and highly harmful plant pest
species. The management of
B. tabaci has been typically carried out by chemical pesticides. In the last
decade however, there has been an increasing interest in natural products, particularly those of plant
origin, to control this pest species. In the present work, aqueous and ethanolic extracts of native plants
from the flora of the Yucatán peninsula (
Acalypha gaumeri
,
Annona squamosa
,
Carlowrightia myriantha,
Petiveria alliaceae and
Trichilia arborea) and the introduced plant
Azadirachta indica
were
collected and evaluated for insecticidal activity against eggs and nymphs
Bemisia tabaci.
Results: Most of the aqueous and ethanolic extracts showed high insecticidal effects on
B. tabaci
eggs. The lowest LC
50 values were recorded in the aqueous extracts of
A. gaumeri (0.39% w/v),
A.
squamosa (0.36% w/v),
P. alliaceae (0.42% w/v) and
A. indica (0.30% /v), as well as in the ethanolic
extracts of
P. alliaceae (2.09 mg mL
-1) and
T. arborea (2.14 mg mL
-1). On the other hand,
B. tabaci
nymphs were not affected by the aqueous extracts, but were highly sensitive to the ethanolic extracts
of the tested plants. The lowest LC
50 values were recorded in the ethanolic extracts of
P. alliaceae
(1.27 mg ml
-1) and
T. arborea (1.61 mg mL
-1). The GC-MS analysis showed that phytol was the major
component of the ethanolic extract of
P. alliaceae and fatty acids were the major components of
ethanolic extract of
T. arborea.
Conclusions: Overall, results suggest that ethanolic extracts of
P. alliaceae and
T. arborea leaves
showed the highest insecticidal effects on eggs and nymphs
B. tabaci. The extracts from
P. alliaceae
and
T. arborea are good candidates to be developed as sources of natural insecticides for the
management of immature
B. tabaci since their effects were comparable with that showed by the
extracts of
A. indica, a well-known plant species for its insecticidal activity.
