Slc. Jewel box scale insect infestation and discolored leaves

[LiveLaughGrowOrchids]

Hi all, I've got a new orchid, it's labelled as an Slc. Jewel box and has gorgeous orange flowers. The leaves are a bit spotty and when I cleaned them a black powdery substance came off and the leaves are dis colored. It came from a local hobby grower who grows them outside/in a shade house. I noticed a scale insect infestation today and the books I've read say to use a systemic pesticide. I'm not sure what to use?

[silken]

Make sure you keep it away from other plants. Scale is nasty and difficult to eradicate. Not sure what you have in your part of the world, but a pesticide containing imidacloprid is a systemic that works. In North America we get Merit in Canada and there is a Bayer 3 in 1 product in the U.S that I hear members using. In the meantime, clean up what's you can by scraping them off.

[bil]

Imidacloprid is very good as a systemic. I use it a lot on scale and other pests. I use a second dose two weeks later to mop up survivors.

It is sold a Confidor, which is expensive. Better to get a generic version (there are several) that is usually a quarter of the price. They sell it in small bottles here, but they work out at 20 times the price per litre.

There is another, CHAS 48, but be very cautious. I've damaged a couple of non orchid plants by making it a bit too strong. (Classic English Syndrome, always add 'one for the pot'.) Get the dose RIGHT, or else. Having said that it is damn effective.

I am currently dealing with some nasties in the jungle that grows on the terrace. Large scale, thrips, normal scale, cochinilla and something else that is trying to get a toehold. The whole area is getting hit with imidacloprid, then a week later CHAS, then after another week imidacloprid and then a final CHAS at the end of the month.

I bet one of them comes back tho.

[ALToronto]

How do you use these products? Spray with them or water the plants with the solution to 'poison' the plants?

[silken]

Originally Posted by ALToronto

How do you use these products? Spray with them or water the plants with the solution to 'poison' the plants?

I do both. The merit we seem to be able to get is granular (apparently there is a high potency liquid out there). But I usually mix it in water and it makes a cloudy mixture. I soak the leaves and pseudo bulbs with it. But then I also sprinkle the granules on top of the bark. They won't fall thru. It is made to get very sticky when wet and cling to the surface. So every time you water, some is going thru to the roots.

The Bayer product is a spray as far as I know but I've never seen it in Canada.

If the infestation is real bad, I replace all the media and first soak the entire plant in a water bath of the stuff for an hour or two before potting. I don't like scale and deal with it quickly and aggressively when I see it.

[bil]

The liquid dose is 1 cc per litre. I spray it all over the leaves and stems. It's systemic, so it kills everything that feeds on any part of the plant.

I would repeat, redose after two weeks to get what may have hatched out of eggs, as the pesticide won't kill eggs.

[euplusia]

As scale are insects, they undergo a development from eggs to larvae (nymphs) to adult form (imago). Many systemic insecticides only kill the adults sucking on our orchids. They do not kill eggs and larvae. Larvae are 'crawlers' , living in different habitats from different sources of food. They are often located in small cracks away from plants.
Understanding this you know why at least 3 treatments are needed. Imidacloprid is effective and still on the market as a spray, though a bit expensive. Dimethoat is also cheap and effective, but being a neonicotinoid it is also toxic to higher creatures. Spirotetramat is the third compound in my treatment, it is safe for humans and works long but is only sold in containers of 1 liter.
You can spray all these compounds or drench your plants if you have only a few.

[bil]

Are scale hemimetabolous? If so their larvae will still feed on the plant. I am pretty sure that they are, as are cochinilla, big scale and so on. (Please correct me if I am wrong.)

It's holometabolous insects like butterflies, flies, beetles etc where the larvae feed on different foods to the adult.

[euplusia]

Originally Posted by bil

Are scale hemimetabolous?

I don't know. But to my knowledge the larvae are everywhere and not restricted to the orchid plants.

[bil]

Originally Posted by euplusia

I don't know. But to my knowledge the larvae are everywhere and not restricted to the orchid plants.

I'm pretty sure they are hemi. Yeah, you will find them all over as the nymphs spread out.

To give you an example, I was sitting on the terrace having a coffee, and a cochinilla nymph fell onto my hand, literally out of the sky. They are destroying the prickly pear, and the nearest one is hundreds of yards away. Given they balloon, they are coming down all over!