Combinations of pirimiphos-methyl and carbaryl for stored grain protection

In laboratory experiments, whole wheat was treated with pirimiphos-methyl or carbaryl or combinations of these two insecticides; the treated grain was then adjusted to a 12% moisture content and stored at 25°C for bioassay at various intervals over a period of 39 weeks. Pirimiphos-methyl at 5.1 mg kg^?1 effectively controlled Sitophilus granarius (L.) and Tribolium confusum Jacquelin du Val but was ineffective against Rhyzopertha dominica (F.) CRD 118, a strain showing malathion resistance. Conversely, carbaryl at 6.5 mg kg^?1 (but not at 3.1 mg kg^?1) was effective against R. dominica, but ineffective against the other two species. A combination of pirimiphosmethyl + carbaryl, at 1.8 + 5.1 mg kg^?1, controlled S. granarius and R dominica but not T. confusum, whilst a 4.2 + 3.4 mg kg^?1 combination was relatively more effective against T. confusum but less so against R. dominica. In a separate experiment, whole wheat was treated with carbaryl at 2.5, 5.0 and 7.5 mg kg^?1 (nominal rates). Samples were stored and, at various times after the treatments, were bioassayed with R. dominica CRD 2, at 20, 25, 30 and 35°C. The results were comparable with those for the CRD 118 strain, but efficacy was reduced at higher temperatures. The combination of pirimiphos-methyl at 4–5 mg kg^?1 and carbaryl at 5–6 mg kg^?1 is suggested as a potentially useful grain protectant where R. dominica is a problem and long term storage is required. These results are discussed in relation to the protection of stored grain in Australia.     

Alkyl aryl ketone oxime O-ethers: A novel group of pyrethroids

The alkyl phenyl ketone oxime O-benzyl ethers are a new group of insecticidal compounds. Although they lack the ester linkage, they resemble the pyrethroids in general, and the esters of 2-phenylalkanoic acids, in particular fenvalerate, because they show similar physiological effects on isolated nerve preparations and on whole insects; they also show a similar pattern of change of biological activity in response to structural change. The compounds may exist as two geometric isomers, of which only the (E) series shows significant biological activity; this observation appears to have some bearing on the relationship between conformation and activity in the pyrethroid series as a whole.     

世界猪病的发展与演变(续)

17 群体水平上的复合病因网络 在集约化生产系统中,我们面临的大多数疾病都有着复杂的成分因素。其中一些可能是必要因素,如果没有他们的存在疾病也就无从发生,但当他们独自起作用时却并不是充分原因。“Koch’s”假设有其局限性,只有对疾病病因作现场检验时才起作用。那些病原单独存在并且是必要充分原因的疾病通常是最易     

Effectiveness of the (+)-trans-chrysanthemic acid ester of (±)-allethrolone (bioallethrin) against four insect species

The activity of the (+)-trans-chrysanthemic acid ester of (±)-allethrolone (Bio-allethrin) is shown to be superior to that of the (±)-cis, trans-isomers (allethrin), against houseflies, two species of grain beetle and larvae of the yellow fever mosquito. The efficiency of the (+)-trans-isomer compares favourably with that of pyrethrins when each is used alone or with piperonyl butoxide.