| dc.description.abstract | The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is an important
polyphagous pest that infests many plant species world-wide. The acaricidal, ovicidal and
repellent activity of different extracts of Syzygium cumini L. fruits were evaluated against T.
urticae under laboratory conditions in the Department of Entomology, Hajee Mohammad
Danesh Science and Technology University (HSTU), Dinajpur. The S. cumini fruit extracts were
tested at 0.5, 1.0, 2.0 and 3.0% concentration. All the extracts had direct toxic and repellent
effects on T. urticae. Mortality percentage was gradually increased with the increase of doses.
The methanol extract showed the highest mortality (96.87%) of adult females followed by
ethanol (91.66%) at 3% concentration. The LC50 values of methanol, ethanol, acetone and water
extracts for adult females were 0.202, 0.281, 0.375 and 1.694, respectively and for eggs were
0.233, 0.255, 0.290 and 2.516, respectively. In the repellency test, all extracts showed repellency
effects and significantly decreased the number of eggs on treated bean leaves. The methanol
extract was found more effective as repellent against adult females of T. urticae followed by
ethanol, acetone and water extracts ether causing reduction in egg production per female by
96.73, 94.03, 92.50 and 85.0%, respectively. In persistence test, extract of methanol showed
highest mortality (41.66%) at 1 hour after treatment followed by ethanol (38.33%), acetone
(35.00%) and water (28.33%). The lethal concentration effects of the extracts fade within two or
three days. The result suggested that extracts of S. cumini has acaricidal activity against T.
urticae, and the methanol and ethanol extracts are the most efficient. | en_US |
