Jamnback H, Frempong-Boadu J
Bull World Health Organ. 1966;34(3):405-21.
The early discovery that DDT is extremely effective in controlling blackfly larvae led to its widespread use in control programmes. Recent evidence that DDT accumulates in the food chain has made it desirable to investigate the effectiveness of other, less persistent, insecticides in reducing populations of blackfly larvae.A method of testing larvicides in troughs was developed and tests were carried out with a number of insecticides both in the troughs and in streams in New York State. Fourfold or fivefold differences in the susceptibility of larvae to different formulations of the same chemical were noted. In the laboratory, emulsions were less effective than oil solutions or wettable-powder suspensions. The effectiveness of emulsions under field conditions, noted in the course of their widespread use in Africa, may be due to the ease with which they become uniformly distributed throughout the water even when no special effort is made to ensure even distribution. When aircraft are used to apply larvicides in oil solution the insecticide is similarly distributed in fine droplets resulting in control at unusually low dosages.In trough tests and in streams, methoxychlor and DDT in oil solutions were about equally effective; carbaryl in wettable-powder suspension was highly effective in the laboratory but relatively greater concentrations were required in streams. Abate in oil solution was effective at low dosages in the laboratory and, in a single test, in a stream.
早期发现滴滴涕在控制蚋幼虫方面极为有效，这使得它在控制计划中得到广泛应用。最近有证据表明滴滴涕会在食物链中积累，因此有必要研究其他持久性较低的杀虫剂在减少蚋幼虫数量方面的有效性。人们开发了一种在水槽中测试杀幼虫剂的方法，并在纽约州的水槽和溪流中对多种杀虫剂进行了测试。研究发现，幼虫对同一种化学物质不同配方的敏感性存在四倍或五倍的差异。在实验室中，乳液的效果不如油溶液或可湿性粉剂悬浮液。乳液在非洲广泛使用过程中在田间条件下表现出的有效性，可能是因为即使不特别努力确保均匀分布，它们也能很容易地在水中均匀分布。当使用飞机喷洒油溶液形式的杀幼虫剂时，杀虫剂会以细滴形式类似地分布，从而能以异常低的剂量实现控制。在水槽测试和溪流测试中，油溶液中的甲氧滴滴涕和滴滴涕效果大致相同；可湿性粉剂悬浮液中的西维因在实验室中效果很好，但在溪流中需要相对更高的浓度。油溶液中的双硫磷在实验室中低剂量时有效，并且在一次溪流测试中也有效。
