raising silkmoths (silkworms) - Sericulture, Moriculture, and the wild ones

batch 3 hatched today.  
I'm playing with some filters that are supposed to make the lens do macro.  I'm not happy with the results.  But cute.

Cindy Haskin wrote:Will you be allowing some to breed and lay eggs for next year?

yep

size difference between hatched-today and cocoon tomorrow stages of the lifecycle

(hint, the bottom black dot is the younger one)

Oh Wow! Just showed hubby. He thought the newly hatched was excrement.  I told him he should be ready to see many of these in his future!  He thought maybe he'd be eating them deep-fried!

So this is a fast-paced growth rate and harvest turn around.  Thanks for keeping us in the loop!

weirdness with a couple of my silkworms.

one just decided to spend the day laying on his side.  I think he's about the age to cocoon, but refuses

The other made a cocoon earlier this week, but didn't get very far.  Now he's oozing black goo.

Both are in quarantine and the whole batch is separated from the others.  I was going to breed them, but not now.  

any idea what's going on?  

Purely guessing here. Just something that happens to a few because of the (guessing again)  inbreeding?  I certainly hope it's not something more sinister.  

Cindy Haskin wrote:Purely guessing here. Just something that happens to a few because of the (guessing again)  inbreeding?  I certainly hope it's not something more sinister.  

It shouldn't be inbreeding yet.  I'm only on my third generation and started with eggs from a mixture of three batches.  Stripes, whites, and yellow cocoons.  I'm careful to get a variety and enough mating to keep the genetics lively.

I'm thinking environmental or bacterial.  There is a lot of dust on the leaves that I can't always wash off completely.  But that's drought and wildfire.  

All the ones from this batch seem to be getting sluggish and the cocoons aren't as thick as normal.  

I'm feeling I should just toss the batch to the chickens.  But I want to know what's wrong with them first.  

I found this - but don't see the problem yet.  There are a lot of words and my brain hurts today https://www.peacefulsilkworms.com.au/?page_id=505

As an entomologist, the death of the larvae right at pupation is a red flag. Many diseases reduce the hormone ecdysone inside the insect body--this is the hormone associated with moulting and pupating. The symptoms of low viral load include dying while spinning the cocoon, while higher viral loads can lead to death at the J-stage (as seen in your second image).

Silkworms have a lot of diseases, but I am willing to guess that your worms may have the viral disease nuclear polyhedrosis or qualitative polyhedrosis (aka grasserie) if the black goo isn't foul smelling. If it is, then it's probably a bacterial disease (Bacillus thuringiensis, which is sometimes used as an organic insecticide can cause this, but so can many other bacteria).

There is no cure for most insect diseases--their immune systems are very different from ours. If one more insect from your quarantine batch gets sick, burn the lot of them. Always wash your tools with ethanol and touch them to a flame between handling batches of insects. Wash out your containers well between batches of insects, including ethanol, UV, or some other sterilisation treatment. Sanitation is key when rearing insects!

Is hydrogen peroxide good enough for cleaning?

I'm feeling identification of the ailment is my goal this year.  Then cleaning everything.

This batch had an extremely low hatch rate.

I'll smell the goo in the morning and report back.

r ranson wrote:Is hydrogen peroxide good enough for cleaning?

I'm feeling identification of the ailment is my goal this year.  Then cleaning everything.

This batch had an extremely low hatch rate.

I'll smell the goo in the morning and report back.

If it were me, I'd be cleaning everything immediately, and saving photos for ID later. I worked for a year rearing caterpillars of endangered butterflies, and we nearly lost the whole batch (>6,000 individuals) to a disease, even with alcohol sterilisation, regular (every 1-2 days) paper towel changes, and powerful biocides to sterilise insect chambers.

No, hydrogen peroxide will generally not kill bacterial spores (though it will kill active bacteria and fungi), and is of limited effect against many viruses. A quick search through the scientific literature pulled up this old paper which implies that disease like you're observing can actually be caused by hydrogen peroxide, which would lead me to avoid introducing it to the enclosure:

Ishimori, N., et M. Osawa. 1952. Provocation of polyhedral disease in silkworm by injection of hydrogen peroxide. I. Hydrogen peroxide treatment. Kgaku to Seibutsugaku, 22(4), 172-176 (in Japanese)

Another option would be to use a pressure cooker or pressure canner to steam sterilise your equipment; will work for glass and metal, could be alright for wood, but probably a bad idea for most plastics.

My bins are plastic.
I'll move the infected batch into a box that will be burnt.  And into another room away from my studio.  I'll get the photos tomorrow then plan to burn them.  

How about chlorine bleach?  I don't like to use it, but the bins will have a few months to air out before next spring.  

The plastic bins are the only thing I use from year to year, except the clippers for cutting branches - but these get an alcohol clean most weeks so they don't transfer illness from tree to tree.  

...

I am worried about the way the weather is influencing the mulberry trees this year.  The leaves feel tougher/dryer than normal and there is more dust that is tough to get off.  I wash down the trees every few days, but there is just so much dust and soot in the air that it's hard to get the leaves clean.

But my instincts tell me this isn't the cause of the problem.

I checked, and there's no moth spray this year.  Sometimes they spray for gipsy moths in april and may.  

r ranson wrote:My bins are plastic.
How about chlorine bleach?  I don't like to use it, but the bins will have a few months to air out before next spring.  

...

I am worried about the way the weather is influencing the mulberry trees this year.  The leaves feel tougher/dryer than normal and there is more dust that is tough to get off.  I wash down the trees every few days, but there is just so much dust and soot in the air that it's hard to get the leaves clean.

But my instincts tell me this isn't the cause of the problem.

I checked, and there's no moth spray this year.  Sometimes they spray for gipsy moths in april and may.  

Chlorine bleach is an effective disinfectant. Definitely look into using soap & water plus a UV bar light if you want to move away from using bleach, though--particularly if you're re-using your greywater. How often are you sterilising the bins? Standard practice is to do so once a week, changing the paper they're on every day or every other day, depending on how big/messy they are. Frass can start moulding within 24h in the insect rearing environment (warm, high humidity), which can make the caterpillars more susceptible to disease.

Soot? As in ashes from local wildfires? This could be quite harmful to silkworms, as ash mixes with water to form lye. Additionally, the wildfire ash being generated in the PNW will have other nasty stuff in it including toxic breakdown products of burning plastics from fires going through residential areas. Consider adding vinegar to your leaf wash mixture--this will also help disinfect the leaves, and the acid will help to neutralise the lye and lift the dust off as well. If it's stubborn, consider trying to shift it with a bristle brush or dishcloth.

I encountered issues with leaf contamination before--the leaves created a small amount of suds when washed in pure water. Even after double rinsing them as a precaution, our younger caterpillars (about halfway through their development), and had trouble -- vomiting, diharrea, and death occurred. I wish I had been able to try vinegar at the time, but we had to follow strict protocols. Never found out what it was, but it was the same conditions--droughty, late summer tough leaves that had some contamination. It's a tough time of year to be a caterpillar!

Best of luck--do keep us posted with how your silkworms are doing.

UPDATE:

- poorly batch.  The last one has finished starting a cocoon today.  One more possible black goo, but we'll see.  The cocoons are not as thick a silk as normal.  I'm going to leave it a few more days before stifleing them.  

- younger batch (not sick yet, but not thriving as expected).  I changed the way I harvested the leaves.  Before, I was washing the trees with the hose every other day and then just picking the leaves, putting them in the fridge.
Now I'm picking a foot or so of branch, washing in the sink with just (purified and filtered well) water, then putting the branch in a vase of water for at least 6 hours prior to plucking off the leaves and feeding the worms.  This seems to plump up the leaves and make them less leathery.  But they do seem to only last about 48 to 36 hours before starting to wilt.  
But, the 'worms' (I always feel weird calling them that) are more energetic and eating considerably more on this new style.  
So definitely need to pay more attention to my leaf cleaning in the future, and take extra action to make sure the leaves have enough moisture so the worms don't dry.  
I don't know if that's the cause - but it does look like it is making a difference and bringing the little guys up to health that they can fight off whatever it is back to subclinical.  

Glad to hear that small changes seem to be making a big difference! I like the concept of having a vase for mulberry branchlets to pull up more moisture before feeding them to the little guys.

I can't wait to get my own started, if it ever happens. First I'll have to plant the mulberry trees and wait a couple years for them to be big enough to feed a population of silkworms. And just getting there is still another couple of years off! Oh how I hate this forced waiting. It's because we will need to have saved enough currency to get us through nearly another 2 years before taking early "retirement". By then I'll want to bank what time and energies I have to getting the infrastructure in place for our little homestead with my daughter and grandkids.

I'll keep sending healthy energies to you and the critters in the meantime!

I made a video for you.



If you liked it, please pop over to youtube and give it a thumbs up

Especially if you want to see more videos about silk and silkworm raising.

Silk worms are actually quite tasty. After you boil them to get the silk thread, take the bare pupae and fry them in sesame oil, then when they're kind of crisped up, coat them in teriyaki sauce and put them on skewers. They're good to freeze like this if you don't want to eat them all at once, and the frozen ones are good to throw on the grill as an appetizer for your next bbq. Waste not, want not.

Ryan Hobbs wrote:Silk worms are actually quite tasty. After you boil them to get the silk thread, take the bare pupae and fry them in sesame oil, then when they're kind of crisped up, coat them in teriyaki sauce and put them on skewers. They're good to freeze like this if you don't want to eat them all at once, and the frozen ones are good to throw on the grill as an appetizer for your next bbq. Waste not, want not.

Still gathering up the courage to nibble on mine, but it's also hard to deprive the chickens of their most favourite food.
If you have any tips on cooking or recipes, we have a thread all about eating silkworms.  https://permies.com/t/114600/Cooking-Eating-Silkworms  

Took a teaspoon of eggs out of the fridge today.   A bit late this year,  but I  hope I have enough time for two batches.  

r ranson wrote:Took a teaspoon of eggs out of the fridge today.   A bit late this year,  but I  hope I have enough time for two batches.  

I want to emphasize how much this is.  

When I first started raising silk, I had bought 1/16th of a teaspoon and I was completely overwhelmed.

My trees are much larger now and I don't have as good a hatch rate as I would like yet.  But I would like to scale up this operation over the next few years.  

the plan for this year
- to focus on my eggs saving technique to improve hatchrate
- to find a better cocooning setup

Hatch day today

I've been keeping a humidifier on at least half the time, so I'm hopeful that we can get a better hatch rate

This is so cool! Wonder how I didn't see this thread before... Any updates on the project for this year?

By the way, on a related subject, do you know if it's possible to extract silk from any species of other moth families besides Bombycidae? I've wondered about Yponomeuta evonymella (bird-cherry ermine). It's native here, and does produce loads of silk, but no idea if it would work the same. Mulberries are marginally hardy in our climate, so it'd be cool if there was a wild moth with usable silk...

Eino Kenttä wrote:By the way, on a related subject, do you know if it's possible to extract silk from any species of other moth families besides Bombycidae? I've wondered about Yponomeuta evonymella (bird-cherry ermine). It's native here, and does produce loads of silk, but no idea if it would work the same. Mulberries are marginally hardy in our climate, so it'd be cool if there was a wild moth with usable silk...

Silk is generally extracted from the cocoons moths wind around themselves to pupate -- the species that do this wind a continuous strand around themselves; when you reel silk you unwind this strand continuously and get a single extremely long strand which can be spun into a fine thread when combined with those from other pupae. Yponomeuta evonymella has a hard pupae with no silk, so this is not an option -- the silk the larvae spin to protect themselves is quite dirty with frass, but you might be able to take the lot, wash it, degum it and see if you can spin it like you would a silk cap or hanky.

There are a heap of other moth species with silk cocoons that have been used to make silk over the centuries -- here's a non-exhaustive list to start with.

I'm reading a PDF about edible houseplants, and the author is wrote this:

Studies in China report that certain silkworms will eat not only mulberry but other leaves, and the silkworms themselves grow rapidly, taste good, and are very high (± 60%) in protein. The human-essential amino acid content in silkworms is two times higher than in pork and four times than in egg and milk.  

I'd definitely need to do research as to the "certain" silkworms referred to, as growing enough mulberry to make this a practical option, would be difficult. I wonder if one could freeze the leaves for later ingestion?

source

Thinking this year might be my last year.  Mostly, I'm just doing this to keep the eggs alive.  And maybe get some final photos.  

But it's finally warm enough to start hatching them out so we'll see how it goes.  

silk "seeds" put out this morning.  

Going to use the studio room instead of my bedroom since the weather is finally hot and I don't need to use a small room with the heat on.  The only big difficulty will be keeping the sun off the bugs as this seems to make them grow a lot slower.  

Jay Angler wrote:I'm reading a PDF about edible houseplants, and the author is wrote this:

Studies in China report that certain silkworms will eat not only mulberry but other leaves, and the silkworms themselves grow rapidly, taste good, and are very high (± 60%) in protein. The human-essential amino acid content in silkworms is two times higher than in pork and four times than in egg and milk.  

I'd definitely need to do research as to the "certain" silkworms referred to, as growing enough mulberry to make this a practical option, would be difficult. I wonder if one could freeze the leaves for later ingestion?

source

I think those frozen leaves would be mush upon thawing. Id suggest you plant a few trees a few years ahead of starting silk worms, unless you already have them growing!  I've got trees I need to remove before I can plant mulberry primarily because I have power lines over my prime space, and the next best location is where trees have been allowed to grow as the sprout!

The first few hatched today.

How are the tidbits doing?

poor hatch rate and slow growth - but I haven't kept them in a high humidity warm room.  They are in the main house which is influenced by the weather so the temp goes up and down during the night.

Some are on the second or third instar.  Many are trying to escape because I keep missing meals.

I don't think my heart is in this this year.

They are starting to cocoon now.  One did about 10 days ago but it didn't look like it was at the right instar.  

The weather has been way too cold for them and they are only getting three large meals a day instead of their usual nine.  My heart is just not in it and I can't see any reason to keep the eggs this year as no one else in town wants to raise moths.  

I had no idea how warm silk is!  I have a thin (inch thick), coarse, raw silk comforter that my mother brought me back from China.  Very rough hewn, nothing fancy.  I had to put a duvet cover over it so my dog wouldn't pull it apart when she gets in bed.  This winter I realized it is warmer that my huge fluffy down comforter!!  I had no idea silk is that warm!  It is not even tightly woven.  I thought so little of it that I had it in storage for six years.  Now I am considering raising silk worms too!

Jen Anderson wrote:I had no idea how warm silk is!  I have a thin (inch thick), coarse, raw silk comforter that my mother brought me back from China.  Very rough hewn, nothing fancy.  I had to put a duvet cover over it so my dog wouldn't pull it apart when she gets in bed.  This winter I realized it is warmer that my huge fluffy down comforter!!  I had no idea silk is that warm!  It is not even tightly woven.  I thought so little of it that I had it in storage for six years.  Now I am considering raising silk worms too!

Silk usually feels very cool, it is desirable in hot, humid climates. But it is also usually paper thin. What makes yours an inch thick?

When the raw silk fibers are stretched and stacked and made into batting, they are airy and have good insulation.