| 【Objective】The study was conducted to explore the effects of Strophanthus divaricatus on the toxic
activity, climbing ability and walking ability of Solenopsis invicta Buren.【Method】The toxic activity of S. divaricatus
against the red imported fire ant (RIFA)was assayed with water immersion soil treatment method.【Result】S. divaricatus
had good toxic activity and behavioral inhibition on small and medium RIFA workers. After treated with fresh smashed
leaves of S. divaricatus (0.5 g), the mortality rates of small RIFA workers with soil depths of 0-1.2 cm, 1.2-2.4 cm and 2.4-3.6
cm were 80.00%, 60.00% and 85.33%, and those of medium RIFA workers were 37.33%, 34.67% and 40%. After treated
with fresh smashed leaves of S. divaricatus (1 g), the mortality rates of small RIFA workers were 50.67%, 62.67% and 88%
respectively, and those of medium RIFA workers were 33.33%, 33.33% and 40%. After treated with fresh smashed leaves of
S. divaricatus (2 g), the mortality rates of small RIFA workers were 90.67%, 88%, 73.33%, and those of major RIFA workers
were 18.67%, 28%, 12%, respectively.【Conclusion】S. divaricatus has a good lethal effect on small and medium RIFA
workers and it can significantly reduce their walking ability and climbing ability. It has stronger insecticidal activity and
behavioral inhibition on small RIFA workers than that on medium RIFA workers. S.divaricatus is expected to become a new
material for the control of RIFA. |
