Parasitic wasps vs. whitefly

[aspasia]

Hi, Group -

I am in So.Calif. coastal - 24/8 I think.

Question about whitefly on hibiscus.

Some ? 8-10 years ? (lost track) I bought some pretty expensive hibiscus from the Huntington at their annual plant sale. The huge blooms are gorgeous, but the plants are infested with whitefly and the leaves are disgusting.

Have had nothing but *+^%(_#(*&^% with these plants. Nothing works - not daily spraying, not mulching with worm castings, not those little sticky cards -- not even even a recent -- very reluctant -- dose of Malathion.

The Huntington told me their hibiscus are free of white fly because about four years ago they acquired "parasitic wasps" from the "UC Riverside Program". (Putting their actual words in quotes.)

Before approaching UC Riverside, may I ask the group:

Can a mere civilian gardener get/manage those wasps?

Would they wander around and sting me?

I'd be very grateful for any experience.

I'd hate to tear out these mature plants, but enough is just about enough.

Thanks in advance!

[Lar]

In article , [e-mail] says... :) :) :) Question about whitefly on hibiscus. :) :) Some ? 8-10 years ? (lost track) I bought some pretty expensive :) hibiscus from the Huntington at their annual plant sale. :) The huge blooms are gorgeous, but the plants are infested with :) whitefly and the leaves are disgusting. :) :) Have had nothing but *+^%(_#(*&^% with these plants. :) Nothing works - not daily spraying, not mulching :) with worm castings, not those little sticky cards -- :) not even even a recent -- very reluctant -- dose of Malathion. You will have better luck using an insecticide that would be systemic, it will be taken up into the plant tissue. :) The Huntington told me their hibiscus are free of white fly because :) about four years ago they acquired "parasitic wasps" from the "UC :) Riverside Program". (Putting their actual words in quotes.) :) :) Before approaching UC Riverside, may I ask the group: :) :) Can a mere civilian gardener get/manage those wasps? :) :) Would they wander around and sting me? :) The wasps are tiny things, you would never be bothered by them. You should be able to find them at "natural gardening " type stores.

:) -- :) :) Persephone :) :) :)

[Ann]

aspasia expounded:

I have no tomato hornworm proglem because of parasitic wasps. They just appeared in my garden, however, I didn't introduce them.

Of course you can.

I doubt it. They're very small, and not interested in territory issues like their larger cousins. I have never been bothered by any wasps or bee-types of any size in my garden, except for hornets, both yellow jackets and white-faced.

[Guy Bradley]

The Huntington may be referring to Encarsia formosana, which are parasitic on white flies. I have used these myself, buying them from Biocontrols. In my climate, they don't survive the winter, but in your climate they may and might become permanent residents. These insects are very small, not much bigger than the white flies themselves, so they will never bother you. They do their work silently. Actually, they will never completely eliminate white flies - after all, if they did, they'd have no food. However, holding the population to a dull roar will be sufficient for the task.

Guy Bradley Chesterfield MO zone 6

[David Ross]

The wasps were released to control ash whitefly, which were defoliating ash trees as well as attacking other plants. These wasps have spread throughout southern California. If they are not controlling your whitefly, then the whitefly on your hibiscus is a different species.

I suggest you feed the hibiscus with a granular rose and flower food that contains a systemic insecticide.