Monarch Caterpillars and Swan Plants

Hi, I had two very healthy looking monarch caterpillars who devoured my swan plant. I bought 2 more swan plants on a mercy dash to pak n save one night and transferred them. Both caterpillars soon died and hung in upside down V shapes which the monarch forum posts seem to suggest that there is something wrong with the soil which has killed them

There seem to be a couple of very very tiny new cats on one of the new plants now. Any suggestions on how to save these plants and cats given that the other two died, or should i get rid of the plants and get new ones!

serraangel, Jan 18, 9:09 am

I'd be suspicious that the new plants had been sprayed so that they weren't eaten by caterpillars before sale.If new caterpillars have hatched on them the spray may have worn off by now and they should be ok
But I've not heard of the soil affecting caterpillars.And not sure what you mean by V shapes either, sorry

kateley, Jan 18, 9:49 am

sounds like they had been sprayed.

beebs, Jan 18, 11:01 am

Not sure what you mean either but am wondering if you're aware of what the catarpillar looks like when it hangs upside down (I would say in a J shape) prior to splitting its skin & becoming a chrysallis! Google the Monarch life cycle for pics. If you do indeed mean an inverted 'v' & the remains look depleted, it could have been killed by a particular parasitic insect, a wasp like thing that I can't spell. Will try to google & get back to you.

woody89, Jan 18, 3:52 pm

ah yes i mean the inverted V. like they hang from their middle and literally fold in half and look a little deflated. they were like that for a few days as i wasnt sure if they were just doing their caterpillar thing but once i had a look around the monarch forum other posters had had similar happen to theirs and yeh they were dead

ok so i should get rid of these plants then in case they have been sprayed. wont be getting any more from pak n save!

serraangel, Jan 18, 4:40 pm

probably not necessary to get rid of the plants, no spray stays effective for ever.

kateley, Jan 18, 8:05 pm

Monarch caterpillars can be transferred onto moth plants (google it). The caterpillars will thrive. But get rid of these noxious plant pests as soon as the butterflies emerge as the cruel flowers will kill them. (True! Google this too.)

tune, Jan 18, 10:49 pm

I have 4 swan plants plus lots of seedlings.One plant was being devoured so I transferred them onto the other plants and they all died.Monarchs are continually visiting the other plants but there is no sign of anything growing.No wasps either.There is something about the plants that is not good for them.They are seedlings growing where others have always grown and had caterpillars as well so its very disappointing as there are dozens of butterflies around at the moment.

rona1, Jan 19, 8:26 am

just looked at mine tonight.have lots and my caterpillars are gone and there are ugly red mite things on them.No other plant but them I have seen them on.Bit disappointed as they were doing so well a few days ago

sheepfarmer, Jan 19, 11:14 pm

are monarch catapillers poisonous to birds !
I have been pondering establishing a swan plant area but vaguely recall something about the caterpillers being poisonous and I have resident weka, so while i would net the plants , I want to be sure if the weka managed to abduct any cats , it would not harm them

sorry to hi jack thread

favouriteseller, Jan 20, 12:07 pm

Yes. Google your own words - "monarch catapillers poisonous to birds".

tune, Jan 21, 2:39 pm

Favouriteseller - swan plants are technically poisonous, because of the chemicals they get (and need to eat) from the leaves of the swan plants. However, they just taste bad to birds and birds usually won't eat them after the first taste. They will not be harmful to your birdlife. They don't have any negative impact on any NZ wildlife. More information on Sheepfarmer - the 'red mite' things are probably Oleander aphids. Watch out for ladybirds who will help control them - or you can use some of the safe treatments on (search on aphids). Also, feed your plant well - if you can get seaweed from the beach, or put other compost around the base of the plant, and water it in well.

braenz, Jan 22, 8:48 am

Could be that the plant is too dry and that there is a build up of the chemicals in the leaves, making it too strong for the caterpillars to consume. A good question to ask in the forum on

butterfly-trust, Jan 22, 8:50 am

Suggest you plant these plants somewhere and let them get washed well by the rain (or by watering). Keep them covered, say under an old net curtain, and they will be perfect for next year's caterpillars.

butterfly-trust, Jan 22, 9:37 am

Hi, if you run out of food for the monarch caterpillar again they survive and complete their cycle by eating thin slices of pumpkin.I've done this for years and is always successful.I put the pumpkin into a clean deep container, with like a plastic cover over the top with ventilation holes in it, changing the pumpkin slices every couple of days before it goes mouldy.When the caterpillars are plump and mature and go on the 'march' ready to hang upside down I usually put them outside on the fence or branches of trees.

juliette55, Jan 23, 10:12 am

I only have one plant and about a million caterpillars.Poor things have almost devouged all the leaves and then what .!There is not enough leaves for them all!Oh I just noticed post above - LOL

leigh66, Jan 23, 11:02 am