Is anybody having this problem too? This happened to me last year alot and this year was great untill last week. I have been rearing monarchs for over 10 yrs. As a hobby , my daughter & husband think I am crazy but I love it. Anyway. I find my eggs on the leaves and bring the plant home then the grow an do great. Then they get to the J shape and die just as they start to pupate or just die before they change. I have never seen this before untill last year. I thought it was pestasides ??? Not really sure what the problem was or is. This year started off great I usally start getting my eggs in july then last week they started to die again. I found about 8 dead cats between yesterday and today.
I live in the Bronx New York I get my milkweed all over the area. I drive around till I see a patch of milkweeds pull over and look. I hope somebody has seen this or heard of this to tell me if there is anything I can do to stop them from dying. Thanks in advance for any advice.