Suchergebnisse

The effect of hematoporphyrin monomethyl ether (HMME) activated under visible light on worker behavior of Solenopsis invcita was studied with the potter spray tower method. The results showed that greater than 10 mg/L HMME activated under visible light could reduce the walking, grasping, aggregation, and water and food recognition abilities of red imported fire worker ant significantly, but 100 mg/L HMME in darkness could not affect their abilities or behaviors significantly. Therefore, HMME may be a potential novel insecticide that can be used as a substitute for toxic insecticides for controlling red imported fire ants.

We evaluated the bioactivities of compounds from Cicuta virosa L. var. latisecta Celak. against red imported fire ants (Solenopsis invicta Buren) under field and laboratory conditions. The compounds were as follows: methanol extract; petroleum ether, chloroform, and ethyl acetate fractions from the methanol extract; and the active compound isoimperatorin, which was isolated from the chloroform-fraction. The 7 d LC50 values of the methanol extract, petroleum ether, chloroform, and ethyl acetate fractions and isoimperatorin toward micrergates were 111.20, 214.45, 40.90, 569.67, and 25.73 mg/kg, res­pectively. The corresponding LC50 values toward macrergates were 155.78, 308.38, 75.01, 776.75, and 42.77 mg/kg, res­pectively. Under field conditions, baits containing 0.2% methanol extract, 0.1% chloroform fraction, and 0.05% isoimperatorin efficiently controlled S. invicta, with effectiveness percentages of 95.56%, 97.78%, and 95.56%, respectively on the 30th day after bait application. Such effectiveness percentages were not significantly different from that obtained using the positive control fipronil. The present study showed that C. virosa L. var. latisecta has potential as a natural control agent for the red imported fire ants.

Nowadays, the cooperation between China and ASEAN has received more and more attention. I am trying to figure out the importance of economic integration between Sino-ASEAN through this paper, drawing on the experience of the cooperation between the United States and the European Union (EU), which may finally accelerate the integration process in Southeast Asia.

We discover a consumption channel of monetary policy in a model with money and government bonds. When the central bank withdraws government bonds (short-term or long-term) through open market operations, it lowers re- turns on bonds. The lower return has a direct negative impact on consumption by households that hold bonds, and an indirect negative impact on consumption by households that hold money. As a result, fi rms earn less pro fits from production, which leads to higher unemployment. The existence of such a consumption channel can help us understand the e¤ects of unconventional monetary policy.