Hoya Help!!

Hi I have just joined this forum after viewing some of the other posts - there is a wealth of information here and I am glad to be part of that!

I wonder if anyone can provide me with some advice. I have a Hoya plant indoors (not sure which type though as it was a gift) and I now have millions of little black flies in the room which are slowly spreading throughout the house. (ok maybe not millions, but every day I find at least 20 dead ones around the plant and another 10 flying around). I have tried drying out the soil more which is fine until I water again at which point they re-emerge. I have also tried using some bug spray specific for plants which again seems to get rid of the short term problem but not eradicate them completly. I have read elsewhere that in this case I may need to repot the plant in fresh sterilised soil, but I am not sure when the right time is to do this.

Is there anything else I can do to get rid of these flies!?

any help would be greatly appreciated.

 

Hi Australis and welcome,the problem you have is fungus gnats here's what you can do.
Treatment

Chemical

Products containing the following chemical ingredients are all effective on black fungus gnats:

Imidacloprid
Pyrethroids and Pyrethrin

Note: It is important to read manufacturer's instructions for use and the associated safety data information before applying chemical treatments.
Organic

• Place sticky traps between and around the base of plants to catch adults.
• For indoor plants, the predatory mite Hypoaspis miles can be applied to the soil. The mites inhabit the just area under the soil surface where fungus gnats pupate.
• Water the parasitic nematodes Steinernema feltiae into infested soil. These naturally occurring parasites will infect fungus gnat larvae with bacteria and kill them.
• Letting the soil dry out partially may help to reduce the larval population in pots.

Prevention

• Practice good plant hygiene by removing any old, dead leaves and fungal growth from the top of pots.
• Water plants only when required to prevent the build up of fungal growths.
• Cover the surface of pots with sand as a barrier against egg laying females.

 

http://members.tripod.com/khedlund/hoyapdl/index.html

The link above may help you identify your hoya, if it has flowers. Most common hoyas in circulation are hoya carnosa (green and variegated) and hoya bella.

 

Thank you all so much for your help and your quick replies, most appreciated!

Walnut - thanks for your advice..any pointers on where I can buy the 'parasitic nematodes Steinernema feltiae'? I've just googled it but thats not really indicated any suppliers.

Shiney - my hoya does not have any flowers! I have read somewhere else that giving a high potassium plant food apparantly helps flowers to develop which I am thinking of trying once i have tackled the fly problem. My mum has a similar hoya plant and hers has lots of lovely light pink flowers with a dark pink centre - I am so envious!

Anyone have any other ideas on how to help the Hoya develop flowers?

Ivory - thank you for that link though as mine has no flowers I am still not sure which one it is. I have just identified my mums as being the Hoya Carnosa - absolutely stunning!

thanks again for your help and advice, I will let you know how I get on with those damm flies!

 

You can buy it here Australis http://www.greengardener.co.uk/leatherj.htm
it's also used to treat leatherjackets in lawns it's expensive and rather a large quantity minimum size.
Try watering from the bottom put a layer(8-10mm) of fine sand on top of the compost sticky traps for any on the wing although these will die out when deprived of access to the compost.

 

I find that the hoyas that I have grown, and its not many, only bella and carnosa, tend to like dryish conditions, so my guess would be that if you are getting problems with the tiny black flies then the soil is too moist.
These flies are usually a problem with peat type based composts I find anyway.

I think if it was mine I'd give it a repot into a a JI mix with some sharp grit added, before the growing season ends.

 

thanks walnut, though they seem to sell huge quantities which seems a bit like overkill for my one little plant! i found a website called defenders.co.uk which sell the Hypoaspis - i think i am going to try that one - chemicals i would rather not bother with unless absolutely neccessary.

Pete - is now a good time to repot? and can i ask what a JI mix is?

thank you all once again

 

JI, stands for John Innes, its a loam based compost that tends not to suffer from that particular pest.
A careful repot could be done now, although I have no idea as to the root growth of your plant, size etc.

 

I agree, Hoyas like it dry. they may look like trailing ivy, but they are succulent plants.