Found Two Black Caterpillars Today

[Gwynne]

I keep my caterpillars of the same size together and try not to put too many in a container. When I am feeding, I start with oldest to youngest. I figure that the older ones are less likely to have horrible diseases or they would have been noticed by now. I may be totally off base, but that is my rationale. I wash my hands after handling each group.

I had 20 eggs and maybe a couple of baby caterpillars. I think the two caterpillars I am referring to were from eggs I brought in though there is a slim possibility that they were baby caterpillars. With 20 plus eggs and about 3 baby caterpillars, I can not be sure. Anyway, I was trying the ziplock plastic bag method minus the paper towel. Yesterday I felt I had 10 that were big enough to put in containers. I believe I had already put 10 in two containers a couple days before that. The ones I am talking about were the second group from my 20 plus eggs.

I had two containers with five caterpillars in each, all about the same size. When I went to clean out the containers today and feed them, I found a dead caterpillar in the first container. He had some black on him. Everyone else in that container looked healthy. I am soaking the first container and moved the other four, who look healthy at this point, into a fresh container. When I went to the second container, there was another dead caterpillars, even blacker than the first one! Does this mean I am dealing with the dreaded OE virus? The other caterpillars appeared healthy. I took all eight healthy ones and put them together because I figured they had all been exposed to something, probably the same thing, and they were small enough that I felt they could go in one container. I wouldnt have mixed the two groups if one was all healthy.

Are these guys all doomed because of the two black ones? And what about my other caterpillars? This woman I talked to once made it sound like OE spores just hang around in the air and can infect any caterpillar. I dont know for sure if I am dealing with OE. I had two other caterpillars die that were with the group that just pupated, but that was when everyone was small and they didnt turn black. They just sort of shriveled up. I changed containers and didnt lose anyone else from that group.

I just bought the Live Monarch Castle and it arrived today. I am afraid of putting anyone in it because what if they are infected? And I know this sounds dumb, but I had to walk by the Live Monarch Castle when I was disposing of the two caterpillars. I didnt touch it or anything, but I was imagining spores just jumping off the caterpillars and lunging for my new Castle, well, just because I heard this is so hard to handle. From what that woman said, technically, the spores would be all over my house!

Any idea if I am dealing with OE? Has anyone else dealt with it? What should I do with the eight caterpillars that look healthy? I dont want to destroy them as I have no idea if they are sick, but certainly wouldnt mix them with anyone else. If they do have OE, how long would it take them to get sick? This is pretty complicated business!

[F3]

This sounds like Nuclear polyhedrosis, a viral infection. There's a very informative page about it here, it will certainly tell you more than I can: http://www.geocities.com/rainforest/2153/np.html

OE seems to be less immediately fatal. For more information, check the Biology page: http://monarchwatch.org/biology/control.htm

[Gwynne]

After I wrote this, I started reading and came to the conclusing that it was more likely nuclear polyhedrosis than OE. One article I read was so scary, said once nuclear polyhedrosis was in your rearing quarters, it would be all over the place on the sidewalks outside everything and you would need a new building the rear your caterpillars. That isnt quite possible in my case. The article you have pasted the link for doesnt seem quite so hopeless. I have isolated the eight that were exposed and wont put them with others. Your link mentioned if you suspected a caterpillar had it, isolate it for three days to be sure. I hope that means if the others appear healthy in three days, they are fine. I dont know how quickly it moves through their system, however, and how quickly it makes them sick, so I dont want to assume that the others are fine when it could be lying dormant. I did check the other eight this morning and everyone looks good at the moment.

I would love to have imput from any one who has dealt with nuclear polyhedrosis before and what they did. Maybe that isnt even what happened, but after reading articles yesterday, it seems more likely than OE. Let's just hope it was a fluke.