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Dendrobium Beetles - Stethopachys formosa Time to revisit

Dendrobium Beetle Stethopachys formosa      The Destroyer!!!
As The Australian Orchid Nursery is located 75 kilometres south east of Melbourne we have no epiphytic orchids or ferns within 300 kilometres of us. As a result, there are no natural orchid pests such as Dendrobium beetles down here!
Our cold winters don't allow them to survive. It seems they start around Lakes Entrance in far east Victoria and then go all the way to Cape York in north Queensland. I have only seen them in the wild three times. Once at Merimbula on an isolated outcrop of Dendrobium speciosums, once at Brogo NSW, and finally on the Atherton Tableland munching on Dendrobium speciosum pedunculatums.
I would try Diazonon for an instant kill of the grubs, followed by Confidor pills to stop re-infection, then a Carbaryl spray over the leaves and blooms to take out the adults eating.
For those that like using the bigs guns for commercial control there is a PDF below on the subject. Its the online Wiley one.
If you have any tips for helping get rid of Dendrobium beetles, please comment below!
Over on our Facebook, Phil has one piece of advice that I'm sure has 100% effectiveness!
Here are some great links though to make you all experts.

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  • John on

    Fill any large container depending on the size of your plants with bigger specimens a wheel barrow works with water dunk plants until they surface then you know what to do throw in some fertiliser if you want and you have killed 2 birds with 1 stone

  • Linda Rowe on

    All my orchids(not just dendrobiums) are outside and unprotected, either in the ground or in hanging baskets and they were all attacked by the Beetle, to the extent they were bare sticks and hadn’t flowered for several years. For the past two months, I have been spraying them every two weeks with a Carbaryl solution of 3ml to 500ml water. I give them a good drenching, especially on the stems where the new leaves connect. They are all miraculously coming back, new growth and flowers everywhere. I initially tried spraying once a month with 5ml/500ml but the new growth was still being destroyed so weakened the solution and every two weeks is working beautifully.

  • Rosemarie on

    The rotten little suckers will even find their way into a bush house . I know . If someone has a secret deterrent then I would love to hear or see it . Has anyone tried neem oil ? I worry that these sprays will damage the plants .
    I have recently found the odd 1 sucking and nibbling on my long awaited flowering . Such a huge disappointment .

  • ROb on

    These Beetles just wait for new growth and particularly the annual flowering sprout on my Cooktown orchid.I wait all year to see these beautiful flowers only to have them eaten by this rotten Beetle. How they know ,is beyond me but by the time you spray your orchid these guy s have already done the damage. They must use scent to detect new growth. Maybe some smelly deterant is the fix.

  • Wayne Turville on

    Maybe condsider trying yellow or blue sticky traps next to plants.
    Speciosum blooms are YELLOW!

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