Cleistocactus strausii
As a houseplant, the Silver Torch cactus is an easy to take care of so long as over-watering is avoided. To naturally simulate the porous effects of the sand in its native habitat, it's important to ensure that excess water will not pool in the soil, causing the roots to become water logged.
This plant’s native habitat does not have winter, but when temperatures drop to the low twenties, it can exhibit signs of tip frost. 
The Silver Torch cactus is most susceptible to 
mealybugs 
and spider mite.
Cactoblastis cactorum
Other methods include identifying infected areas and then mechanically destroying all cacti in that area. Crude methods such as these are being used in Louisiana to eliminate the presence of the moth in swampy areas and generally involve the heavy use of removal by chainsaw, hacksaw, or other mechanical chopping device. Chemical pesticides in most areas have proven to be ineffective due to the large quantity and frequency of treatment of pesticide needed to limit the population and also the effective protection the moth is allotted by the cactus leaves.