Mysterious black spot disease

Dynastes

Dynastes

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I have my own theories but anyone familiar with this disease have any ideas on it's cause? I'm referring to the multiple small black spots versus large damage spots.

 
Orin said:
I have my own theories but anyone familiar with this disease have any ideas on it's cause? I'm referring to the multiple small black spots versus large damage spots.
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Hi Orin,

My guess was nematodes, or parasitic mites. I've personally never encountered the small black spots before but another thought would be a parasitic wasp searching for a tender spot to lay an egg subdermally(is this a word?).

Joel

 
I think it is connected with fungus. I'm trying to breed European rhinoceros beetle (Oryctes nasicornis). I've found larvae with these spots .In few days these larvaes died and some days later i noticed that their bodies were covered with a some sort of fungus. I quess that you have the same problem.

 
In know that Thread is old but, if some one is interesed for it :

Black spot is an infection with Coccidia (Adeleidae).

If you want to know for more, i have read some about this disease.

(not only from J.T. Lai...
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Greetings,

Mashku.

 
i was just going to say that J. Lai mentions the melanin being the cause of the dark spot, a reaction to the bacterium attacking the grub... but... I do wnat to know a bit more Mashku, could you enlighten me a bit please
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Same thing happened to my larvae.

Usually these black spots are more common in the larvae of Rhinoceros beetles than the stag beetles. However, for some reason these black spots appear very commonly in the larvae of L. elaphus and L. capreolus. I was thinking that this only happens in captivity until I found the larvae with the black spots in the wild. This might be the common disease among larvae and I don't think it is too harmful since my larvae became pupae successfully even with the black spots. But I am not very certain.

 
I purchased some more exotic grubs that had this last November I was a bit devastated the spots spread in a thick blanket that resibled the black bruising freckle spots common to this infliction.

so instead of putting 150 buck worth of grubs in the freezer i decide to try to treat it. So far so good.

I have researched this is caused by cocci bacteria "a common infliction of reptiles"

I have had remarkable success treating it with a reptaid and also baytril .

http://lllreptile.com/store/catalog/reptile-supplies/vitamins-medicines-and-cage-cleaners/reptile-medications-mite-sprays-and-cleaners/-/reptaid-for-250-gram-or-less-reptiles-rept-aid/

I hold down the L3 grub and put the dropper in its mouth giveing them a good clear drop makeing sure they intake some of it."watch for the mouth movements get it past the mandibles but don't get bit"

the appearance of these spots has reduced in size drastically to the tiniest pinhole size spots and one is fixing to pupate.

the drops were applyed twice a week.

One set i am treating with liquid baytril and have the same success.

it is important to remove and destroy all the frass every week to prevent reinfection

hope this helps

 
Sara said:
I purchased some more exotic grubs that had this last November I was a bit devastated the spots spread in a thick blanket that resibled the black bruising freckle spots common to this infliction.

so instead of putting 150 buck worth of grubs in the freezer i decide to try to treat it. So far so good.

I have researched this is caused by cocci bacteria "a common infliction of reptiles"

I have had remarkable success treating it with a reptaid and also baytril .

http://lllreptile.com/store/catalog/reptile-supplies/vitamins-medicines-and-cage-cleaners/reptile-medications-mite-sprays-and-cleaners/-/reptaid-for-250-gram-or-less-reptiles-rept-aid/

I hold down the L3 grub and put the dropper in its mouth giveing them a good clear drop makeing sure they intake some of it."watch for the mouth movements get it past the mandibles but don't get bit"

the appearance of these spots has reduced in size drastically to the tiniest pinhole size spots and one is fixing to pupate.

the drops were applyed twice a week.

One set i am treating with liquid baytril and have the same success.

it is important to remove and destroy all the frass every week to prevent reinfection

hope this helps
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That is very interesting. I never knew that the larvae can be treated with the medicine for vertebrates. Do you mind if I share this information with my friends?

 
Having trouble with the second batch of Cetonia aurata larvae. It has been 2 weeks since I collected them from a pile of old sawdust. About 50% of them have died. One small one is completly covered with white mold, others are not. Some of them are kind of stiff. Almost all of them have formed brown or black spots on them (even the ones that are still alive). Some spots are small (~1 mm) but some are larger patches. The first batch contained also one larvae with a small black spot on its back but that one did not die and even became an adult. I suspect it's the same desease. There were a suggestions that it's a bacterial disease. Are there any good sources on that? I'm interested how this disease can be avoided.

 
Difficult to tell without looking at them. Black spots can be the result of mechanical damage to the skin, what you see is the insect equivalent of a scab, as you noticed larvae with spots like this can survive to adulthood sucessfully. Bacterial deaths usually result in the whole larvae going a blueish colour. I'm wondering if your larvae were slightly damaged when you dug them up - sawdust can be fairly pricky stuff in places so they may have picked up mechanical damage that way.

 
I dont think it mechanical damage. There is no scaring where the spots are. Plus the decaying sawdust is quite soft. I also have Oryctes nasicornis larvae collected from same area and now living in same substrate all separetly. One small larvae also has these spots and is immobile, probably dead. Hven't checked all of them yet.. I try to take some pictures tomorrow.

Anyway it matches the descriptions that other people have had.

http://www.beetlebreeding.ch/beetle-diseases/

 
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Oryctes nasicornis larvae are having these spots too! The L3 larvae (picture), weight 6 grams, had crawled on top of the substrate. Secretes yellowish liquid from mouth.O. Nasicornis L3 black spot.jpgO. Nasicornis L2 dead black spot.jpg

 
Currently over 50% on O. nasicornis larvae have died. All that are still alive have black spots. Some have more some have less. Removed them to different substrate that is less moist. Hopefully some of them are going to make it..

 
I have 12 Lucanus elaphus larvae, 9 developed black spots, 3 have died so far but I noticed them getting weaker days before. The other 6 larvae that have black spots seem big, strong and growing every week but we'll see what happens.

 
Update on my Lucanus elaphus larvae - As of now I only have 2 remaining Lucanus elaphus larvae out of the original 12. The other 10 have slowly died off from the black spot diseases. The two remaining specimens have no black spots on them whatsoever.

 
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