5th instar silkworms, stop eating, not making silk, starve to death (Australia)


New Member
Hi to all silkworms experts,

I need a lot of help, my silkworms never cocoon.
I have been trying to raise silkworms in the last ten years, they all end up stop eating, stop moving, and starve to death.
I have tried different mulberry trees and even grow my own to make sure there is no insecticides.

I bought silkworms from gumtree.com.au. Usually around 30 of them in 2-3 instar.
Pick mulberry leaves, wash and dry them before feeding them. Half of the leaves are keep in fridge (will that changes its chemical?)
Silkworms are kept in plastic box, with normal A4 paper at the bottom, replace everyday. The lid is 10% opened to let air in.
I feed them 2 - 4times a day (there was one year, I fed them 10+ times a day).
During the cold night (15 C), I leave a electic blanket under the box to keep them warm (up to 25C).
Everyday, I pick them up and pat them (will that kill them?)

The silkworms all happily eat and grow fast. In less than a month, they are all big and fat, almost 9 cm long.
After that month, they start to eat less and move less. I thought they are just too fat to move.
Then about two weeks later, they will start to die, not in one go, but in a period of two weeks.
Their poo becomes brown watery, and often blocked their bottom (I think one of the cause of death)
They will shrink and dehydrate. The dead body is stiff and the dead body will slowly turn black <-- the living one still white.

I have read a lot of material. I can't find any reason. They don't look diseased to me. I have attached a photo of them, when they start not eating much.

Help! I have two more months to try another patch.
What have I done wrong? :(


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Chameleon Enthusiast
Im guessing they caught a cold

For me:

just touch leaves to remove from tree.
Dont store or wash leaves, just directly to worms as needed, every other day
Never touch worms
never clean worms. Uneaten leaves are just piled on by fresh leaves, and worms just migrate up
uneaten worms are tossed, i never put them back in the bin

Also i wash everything with a beer brewing cleaner. I use star-san. I keep a bowl next to the worms, and dunk any utensils or fingers in it when i have to interact with the worms.


Site Sponsor
If everything above has been researched and addressed (triple check the food, environment and sterilization) we found that the silkworms do not like to be moved or their cocooning process disrupted. In the early days of our Silkworm farming we came to find that undue stress during this critical time will cause the cocooning process to halt. (Hence, SerenitySilkworms.. lol) Raising 100s of thousands of Silkworms, even in the most exacting of environments, food, light schedules, humidity, temperature, customer made bins and importantly cocooning bins we still get some that will not cocoon.

Do they show signs of being ready to cocoon? Creating an Anchor with silk? Figure 8 head movement? Gut dump?
Wish you luck, keep us posted!


New Member
Do they show signs of being ready to cocoon? Creating an Anchor with silk? Figure 8 head movement? Gut dump?
Wish you luck, keep us posted!

No, they haven't produced any silk. If they do, I should be able to see something between the leaves.
And they don't move, so no 8-head movement.

My last silk died this morning. :(
I will buried him next to the mulberry tree. RIP :p


Site Sponsor
It sounds like you did everything that you could to keep them growing strong and healthy. There are many unknown factors outside of a 100% controlled environment. So sorry this happened... Keep us posted if/when you try again. *fingers crossed.


New Member
Hi all,
I tried again. 23/10, got 12 new worms, 6 plain 6 zebra.
Separated them into 6 boxes.
Always wear clean gloves when I change their bedding (kitchen towel).
No sunlight, no heater, no electric blanket.
Wash leaves before feeding them (I saw tiny bugs on some leaves, so better wash the leaves first).
Still same result! 😫

When they first arrived, I could see tiny little silk on the leave. Couple of days later, no more silk.
They never produce any silk, just like all other silkworms.

Now I suspect it is the mulberry leaves. I got a dwarf black mulberry tree, which produces tons of fruit, not too many leaves. I did a search and somebody said feeding with white mulberry leave (the humungous leave) produce good silk, some other mulberry leave may produce poor silk. And I think my leaves produce NO SILK !

Anybody using small mulberry leaves like me? The biggest leave on my tree is about 5 inches long.

Thanks for your help.


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Chameleon Enthusiast
I use chow and don't have any issues. But yes, I've heard it's important to use white mulberry leaves not red or black. So give that a try next time and 🤞🤞🤞 that works!!


Established Member
The one thing that stands out to me is the mention of the poo being stuck in their butts. When I used mulberry leaves this summer, I had this problem. They would have their poop stuck or had a prolapse (yellow thing) sticking out. After talking to the guy who runs the blog WormSpit, he said it sometimes happens to him and suggested that it may be Septicemia. There are a few kinds of septicemia. I didn't find this mentioned in most common silkworm diseases, I had to google specifically for it.
I lost a whole batch of silkworms, only one tiny female made it to the moth stage. After that nightmare, I went back to using silkworm chow and that batch had only 6 deaths and 82 healthy moths.

Here is the link for septicemia. I hope my story helps someone. I'm definitely afraid to use leaves again.



New Member
Further research for the type of mulberry leaves, now I am pretty sure the dwarf black mulberry tree leave is not for silkworm. :(

I was going around suburbs and found most of them are black mulberry trees. Their leaves look a little bit different from the white mulberry tree.
White mulberry tree's leave is round-teeth on edge, while black mulberry tree's leave has sharp-teeth edge.

Since the silkworm season is over, I am now planning to grow a white mulberry tree, from seed.
This seller mentioned this one is for silkworm. :D

I will come back next year to report the result.
Wish me luck.
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