Buddleia pests

This topic contains 66 replies, has 14 voices, and was last updated by  Anna 5 years, 10 months ago.

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  • #14137

    NormTwigge
    Keymaster

    Today I noticed the leaves on my Nanho blue buddleia were looking like something was chewing at them. Close inspection revealed an advanced infestation of maggot-like grubs on both sides of the leaves. Putting two and two together I did a search and sure enough they proved to be Cleopus japonicus, a biological control brought in from China to help eradicate the Buddleia davidii which grows rife on riverbanks, roadsides and plantation forest margins.

    The insect is a weevil which lays its eggs on the leaves of buddleia bushes. These hatch out and grow into a maggot-like legless grub, a yellow jelly-like blob which eats away at the leaves, defoliating the plant, stunting its growth, and probably eventually killing it. The grub will grow to about 5 mm in length, and then pupates in a cocoon on the leaf,finally emerging as the adult weevil to mate and start all over again.

    The authorities are more than happy with the results, and advised gardeners to spray their plants if the weevil became troublesome to ornamentals.

    I will post some shots to the Photo section.

Viewing 16 replies - 51 through 66 (of 66 total)
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  • #30077

    Anna
    Participant

    9th April 2012….(Upper Moutere, Nelson/Tasman area.)
    This morning I discovered the Cleopus japonicus larvae on leaves on one branch of the Buddleia Weyeriana “Sungold”. I’ve removed the branch and put it in an enclosed container so I can see how they develop.
    So far I haven’t seen it on any of the other buddleias, but will keep a watchful eye out for it!
    Thanks to Norm for alerting us about this pest, so we know what to look out for.

    #29970

    clinton9
    Participant

    I have domesticed buddleias, that had white flowers.
    If weevils destroys my buddleias, I have to replace with lantanas.
    I have to smash the weevils if I see them.

    I do not feel happy as I still not find the buddleia davidii in Thames, for 12 past years.

    #29966

    Darren
    Participant

    Just for the record, I have found Yates’ Super Shield to be totally ineffective against Cleopus japonicus.

    #29689

    Anna
    Participant

    What a pity the weevil has found your buddleias. I have been keeping an eye out here for them, but no sign of them as yet (Nelson/Tasman area)thank goodness.
    I can’t use any spray on my roses, as the stick insects love rose leaves, along with manuka, camelia, and conifers. I like to give them a variety of food.(and one girl has just laid 18 eggs…yippee)

    #29666

    Darren
    Participant

    Bother, I now have Cleopus japonicus, the Buddlja Weevil in my garden. I use Yates’ Super Shield on my wife’s roses, so I’ll try that on the Buddljas and see how that goes.

    https://www.monarch.org.nz/wp-content/uploads/2012/03/Cleopus-japonicus2.jpg

    #27289

    clinton9
    Participant

    Hi members
    I been looked for buddleia davidii in Thames in early 2000s, but I did not find any in Thames.

    Please do not destroy the buddleia davidii as they are important food for our native butterflies.

    Let the weevils and caterpillars of puriri moths do their jobs of controlling buddleia davidii, so we don’t have too many buddleia davidii overrunning the parks & bushes.

    On year 1996 I found few pupaes & caterpillars of puriri moths inside branches of wild buddleia davidii.

    Cheers

    Clinton.

    #27244

    Lynda Finn
    Participant

    A market gardener friend of mine who insisted on all organic bug sprays, once told me that if you collect the nasties (any nasty) and put them in a blender with water, you can then use the resulting sieved liquid as a completely safe spray. I’d be interested to hear if it works with the weevils 🙂

    #25625

    Jennifer
    Participant

    I have had quite a lot of success with Neem oil for any sap sucking or chewing insect troubles. It is not fast acting as it is not a knock down killer but makes tissues unpalatable to the insects. I have also made up a rhubard leaf and soap spray to good effect.

    #25145

    Charlotte
    Participant

    Thanks Norm and with all the Buddleia’s we have around the section it would be a shame to lose them all.

    Char

    #25138

    NormTwigge
    Keymaster

    I waited until the last of the flowers had died back last season and then gave the Buddleia a good hard prune. Actually it was a massacre but Buddlieas will withstand a hack back almost to within a foot of the ground and bounce back all the better the following spring. This of course elimimated most of the weevil larvae and adults, although some had pupated and these overwinter and emerge about now, so a spraying is due before the shrub comes into flower. The weevil is capable of flying so it will spread quite rapidly. Not sure what to use as I detest most insectide sprays, but I may try the seaweed foliar spray and see how that goes, plus picking off and squishing and critters I see in the meantime, although they have not appeared as yet.

    Norm.

    #25133

    Jacqui
    Keymaster

    Hi Norm – any progress on how you’ve controlled the C. japonicus?

    Jacqui

    #23702

    YvonneWallis
    Participant

    It is getting harder and harder to look after the creatures with all these introduced "biological controls" – Makes me more determined to have a butterfly house that i can control to keep alot of these nasties out. Thanks for the info. Norm, I will have to go check out all my plants tomorrow. They all seem healthy enough although one has had curled up leaves that don't appear to have anything in them and was wondering if it is lacking something in the soil.

    #23700

    NormTwigge
    Keymaster

    Hi Jacqui,
    Both Buddleia davidii and Cleopus japonicus come from China, so with Buddleia being the weevils natural hostplant it suits it perfectly. With the infestation on my Blue nanho so bad I doubt the cultivars will be any less resistant.
    The weevil is capable of flying, so as its numbers build it will spread more rapidly. ERMA (Environmental Risk Management Authority) approved the release.
    "Since C. japonicus is an approved biological control it can be legally reared and released throughout New Zealand"
    I intend to try various organic control sprays and will keep you posted.

    #23697

    Jacqui
    Keymaster

    Hi Norm

    On my recent travels I visited a very rural school on the edge of the Uruweras, and saw for myself what a problem B. davidii can be. I wonder if B. davidii will (being a wild, unadulterated species) be more resistant to the bug than the less invasive ones. I guess time will tell.

    Jacqui

    #23696

    mlusk
    Participant

    I was in the Makororo river bed yesterday well into the Ruahine Forest Park. There is a vast infestation of B.davidii up to 10'tall on the river terraces and I think there were more white butterflies feeding on the flowers than I've seen on the fodder crops in the farmaland. I sympathise with the growers of less invasive Buddleias and hope there is a spray that will suit those who avoid pesticides in their gardens, but the problem in the riverbeds is very severe.

    #23694

    Jacqui
    Keymaster

    Norm, this makes me SO mad…

    Cleopus japonicus

    What do we do?

    When you say the "authorities", what do they suggest spraying the Buddleia with? I want to keep my garden poison-free.

    Jacqui

Viewing 16 replies - 51 through 66 (of 66 total)

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