Am not sure if this beetle is also found in more temperate zones or just the tropics but it's a highly destructive pest.
We've put up with this nasty bug for some time now and only today I found out its name, Lema pectoralis.
It feeds mainly on vanda and dendro flowers and can cause substantial damage to the flowers but thankfully not to the plants themselves (thrip damage is worse).
I first came across this beetle when I found purple, slimy feces-like matter on a purple dendro. When I attempted to remove it, the stuff moved! It turned out to be a larvae of some sort covered in its on excretions/feces which takes on the color of the flower it feeds on. Indeed, I found more slimy stuff on a yellow dendro (yellow feces) and more purple ones on a purple phal. They were all larvae. Soon I found adult beetles feeding on the flowers too and a check with my orchid-growing friends confirm that this beetle is responsible for the extensive damage to our orchid flowers.
This entire spray has been destroyed by the voracious larvae:
The larvae cover themselves in their own feces which take on the color of what they feed on:
Sorry for this rather blurry pic as I took all the photos with my camera phone while checking the plants today. The three blurry dots in the center are the eggs of the beetle, one end has turned black (the head) indicating that the larvae are ready to hatch and start eating! I can't take clearer pics as I've squished all that I could find!
And here are two merry little buggers having a good time till they met my bug spray.
Even as the adults prepared to unleash more mayhem, the larvae were busy destroying...
Two larvae on a vanda spike, no longer covered entirely in their feces but rather, totally coated with insect poison, hah!
Here's an interesting article about this beetle, a.k.a. orchid lema - what's written about this bug is exactly like what I observed but this article gives more insight about its life cycle etc. Link:
http://www.bar.gov.ph/bardigest/2003/julsep03_orchidlema.asp
The bugs find orchids that have a pseudobulb, a water storage area originating from the stem and this is where they lay eggs. Burning host orchids is possible, if not, seal them in a trash bag and throw it out.
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