Mohamad Hamshou As per my suggestion, larvae are fed on a natural diet, so I hope to overcome this problem. and also use disinfected rearing materials and proper hygiene.

Manish Gadekar Thank you for your suggestion!. we are using an artificial food which well known for rearing such insect.

in my opinion, both artificial and natural food are OK.

but when we use artificial food, we usually cut the food into little chuncks and we raise all individuals separately Because if the food is too large, it is easy to mold and breed bacteria.

if the worms are raised together,those sick tissues should be cleaned at once, whenever you find some sick or dead worm.

• @Siqi Tang Thank you for your contribution.

Hi Hamshou, we had the same issue. The reason is a virus which they have in latent state but during stress (they are too crowded, your artificial diet is too wet etc.) the infection develops.

We tried the same as you and in the end we started rearing in 12 and 6 well plates, initially adding wooden chips to absorb the moisture and piece of food, later with pooring the medium directly in the wells because the first method takes a lot of time. In all cases use tissue paper under the lid to regulate the moisture and change it regularly. Don't keep too many larvae together. Initially we started with one well - one animal, later we saw we can keep few together but I would not recommend more than 2-3 especially in the later stages.