I've read a number of nematode and fly larvae articles where their skins get too tough for the drugs to be effective in latter stages or instars (there's usually at least 4 instars/stages, which involves the nematode or fly larvae shedding their skins or cases).
This is an interesting article about Mosquitocidal compounds from Magnolia salicifolia which were 100% effective in killing 4th instar mozzie larvae:
"Bioassay-directed isolation and purification of Magnolia salicifolia yielded six mosquitocidal compounds. Geranial and neral, isolated from the bark, showed 100% mortality on 4th instar Aedes aegypti at 100 ppm in 24 hours"
Mosquitocidal compounds from Magnolia salicifolia
This is the main reason I put myself on magnolia tablets this week and started using Marc Neumanns DSP special which has Geranial in it.
On the subject of ivermectin, I've read a number of articles where it was effective on nematodes and fly larvae...mainly talking about treating cattle not humans though!
Cookie Absent
:http://www.jstor.org/pss/2403564
The effect of faecally excreted ivermectin and fenbendazole on the insect colonisation of cattle dung following the oral administration of sustained-release boluses.
This next article is very interesting. Fly larvae are big producers of chitin according to this disturbing report:
"The fly (Musca domestica) larva shells,
which form in rather big amounts as a waste product in the process of biological treatment of food industry wastes!! (shocker) (being sick smiley), can be used as a raw material for chitin production.
These shells contain about 40% of chitin; for comparison, the prawn (Nephrops norvegicus) shells contain approx 16% chitin. Chitosan from fly larva shells may be produced in the same way as from the crustacean exoskeleton.
The key steps in the extraction of chitin from shells are the removal of proteins and minerals, such as calcium carbonate and phospate, by treatment with alkaline and acidic solutions in turn."
http://images.katalogas.lt/maleidykla/che33/C-121.pdf
Just had a thought....Nancy - isnt this what you have been doing to chemically interfere with calcium carbonate making in your lesions?
Jo xxx