Methiocarb - Efficacy

Efficacy

Methiocarb is used as toxin for different purposes. It ranges from snails, insects, rodents and even as a bird repellent. As an insecticide it is effective for thrips and has a low dose that is lethal for these animals. The LC_99,99 for suspension concentrate is 0.34 g/L and for the wettable powder it is 2.30, which is a bit too much for effective use.10

For the use as a molluscicide methiocarb is effective, but at a high dose. In a research with E. vermiculata, methiocarb showed to be the most effective as topical applicant (although DMSO was used as an solvent). The LD₅₀ is 414 μg per snail and the LD_99,99 is roughly estimated 1400 μg per snail for methiocarb. In comparison to methomyl which was more effective, with its LD₅₀ was 90 μg per snail. Which is a lot lower than the LD₅₀ of methiocarb.

As snail bait methiocarb has the same effectiveness as methomyl for 1% (mass percent) and 2%. but the LC₅₀ of methiocarb is higher than the one of methomyl. 0.93:0.31. They both reached an average mortality of 85%, by the use of 2% methiocarb/methomyl bait.

In another comparison study (with M. obstructa) between methiocarb and methomyl. Methomyl showed again to be more effective. The LD₅₀ in this study were 12 μg per snail for methomyl and 27 μg per snail for methiocarb. These compound were topically applied on the snails and these compounds were first dissolved in 95% ethanol and diluted with water to make the concentrations.

As an avian repelled to protect fruit, methiocarb was in one research not effective. The birds still damaged the figs. This happened because the methiocarb was sprayed on the fruit. The birds pinched the fruits or peeled the skin of the fruit and ate the meat of the figs. In that manner these birds are very little or not exposed to the repellent.

In another study with quelea, it was investigated if methiocarb had an adverse effect on the food choice. It showed that when quelea ate seeds with methiocarb, the next time they would chose some other food. This shows that methiocarb can be effective as an bird repellent.

In one study methiocarb is shown to be not very effective against mice as an rodenticide. In the first field trial snail pellet of methiocarb were spread across the land, and killed almost 23% of the initial mice population in one night, but the population did not decrease(probably because of reinvasion of the neighbouring land). There hasn't been searched for carcasses after that, but birds were seen scavenging on carcasses. In the second field trial, grain was covered in methiocarb and strychnine and it showed a mortality rate of 40% for methiocarb and 90% for strychnine. Although methiocarb seems to be effective at first. Mice develop an aversion for the methiocarb, which makes it not very effective as rodenticide.