Friday, August 9, 2013

A hideous little pest of Bletia patula and other local orchids

The damage to the florar parts of Bletia patula flower betrays
 the handywork of a curculionid bettle that attacks the flowers of orchids.

Checking the flower shows that the bettle is hidden behind 
the lip of the flower, sometimes you find two bettles together.

If the bettle feels the flower is being handled, it tries to hide deeper between
 the lip and the petals.  If it is further annoyed it comes out of hiding and tries to flee.

If the bettle comes out of hiding, its usual strategy is to run to
 the end of a floral part and from there fall to the ground.

This particular flower bettle damages the flowers of many kinds of orchids in my garden.  Its local abundance varies seasonaly.  At certain times of the year I can find from one to five chewing in my flowers.  I think this might have to do with the peak of flower production by local plants, but this is just a guess.  Rather than use insecticide on them, I exploit their fleeing response by putting a cup with alcohol or dishwashing liquid under the flower and shaking the flower gently.  The usual result is that the bettle takes a dive into the liquid and then goes to the great orchid flower in the sky.  Thankfully for most of the year they are not present on the garden,    
These bettles are surprisingly hard for such a small insect.  It is not easy to crush them.   But if you are moved to squash them, they do produce a satisfying crunchy noise when crushed.  I have seen damaging flowers of Bulbophyllum, Cattleya, Dendrobium, Oncidium, Peristeria, Sphatoglottis and Bletia among others.

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