I need help with mealy bugs

I had approx 400 hoya's and tropical plants in my 10 x 14 ft. greenhouse overwinter. I ended up getting a very bad case of mealy bugs going. No matter how often I sprayed which was every plant about every two weeks. , I just couldn't seem to get rid of them. I have sinced gotte my hoya's collect down to about 100 plants and have some other plants in there. I am spraying religiously weekly, but still find the meally bugs. I have a gravel floor in the greenhouse and have noticed that when I set new plants on the floor, by the next day they will have mealy's on them. Can anyone tell me what do spray or do to get them cleared out for good?

Patricia

Cleared out for good? I'd say empty the GH, bomb it, and start all over. Seriously.

Control is a different issue.

I still get mealies popping up here and there. I use a combination of control methods. Most the mealies that die in my GH now die from a dap of alcohol on a Q-tip...very effective and well tolerated by the plants...plus, it doesn't harm the mantises which now call my GH home and which, I believe, help with the control. Neem, soap, and pyrethrum sprays are used on the edibles and the stuff on the raised beds, but occasionally you will encounter phytotoxicity with these, so you have to be careful. The water "blast spray" technique is helpful, and some claim to be able to control with this method alone.

I found it very helpful to take the worst offenders (that is, the plants most seriously affected), pot them up into containers (out of the raised beds) and treat the container medium with a systemic...I used imidacloprid.

The egg sacs can be anywhere...cracks in the benches, underneath the pots...look around, find 'em, and get 'em.

Control the ants which, I'm sure you know by now, farm the mealies. I've been reading about a product called horticultural glue that can be used on the trunks or stems of plants to control the ants. I haven't found anyone who can tell me that it is perfectly safe, yet, but I'm still considering it. Brand name is Tanglefoot or something like that.

Here is a link: http://davesgarden.com/forums/t/589012/

I finally sprayed with a combo of Talstar and Orthene and it worked great-I had to follow up once more, and I haven't had a problem with them. Next winter when I start the spring crop. I am going to be really diligent in spraying for these. While the alcohol works, I have way too many plants to stand there and spray with a spray bottle, not to mention the amt of alcohol that I was going thru! I was mixing it half and half with the water.

I spray all the plants weekly with straight alcohol, but then a few day's later I find that I must have had another hatch of them. What I am really concerned about is that since I have a gravel floor, I guess they could also be in the gravel.
I have on occassion bombed the greenhouse with bug bombs, but it doesn't seem to affect these mealy's. I did have an ant problem last summer, but haven't seen many this season. I guess I will empty it out again when we have some cooler day's and spray gravel, walls, benches etc. again.

Thank you both for your input.

Patricia

if you are going to totally empty the grhouse then trying spraying with bleach-straight bleach if you can.

Bleach needs to be diluted with cool water, to be most effective. Even at 1:10 it's quite caustic. Concentrations higher than that can be unhealthy for the environment.

Patricia...get some "Bayer Tree and Shrub" systemic and water all the plants with it (except any plants you are going to eat like strawberrys, or veggies, etc.). It comes in a liquid (looks like chalky milk stuff). You mix it one ounce to a gallon of water (ignore the directions on the bottle as that is for trees etc.). I use an old gallon juice container as I don't do all mine at once. The main ingredient in it is the imidacloprid referred to above, and it lasts for about 6 to 8 months. Just make sure it gets soaked into the soil good so the roots can take it in.
It works like a champ. I used to chase after those mealies all the time with alcohol too. Now I hardly ever see one and if it do it is because the plant has not been done for a long time.
It is mild on them too, in fact they seem to love it and I get lots of new growth right after I treat them. Try it and see if that doesn't cure your mealy problem.
Marcy

Bayer Tree and Shrub is the systemic imidacloprid I mentioned above. I use it exactly like Marcy said, 2T/gal. A couple of plants required two applications, but I can confirm that it does work very well.

I only use it in containers.

Thanks ladies, I think I will start working on that today.

Patricia, I've had a miserable time with mealy bugs this year. Can you tell me how things worked out for you?

Hi Brinda, I took every plant out of my greenhouse. Dipped and soaked each plant in Bayers Tree and shrub for 10 min. Poured 5 gallon buckets of the same mixture through the rocks that are the floor of my greenhouse. Pour hosed down all the walls, channels and tables of the greenhouse. I didn't see any mealy bugs for a few weeks, but now am seeing them again. I am going to go through the whole process again in a couple weeks. I just don't know what else to do. It helped, but obviously I didn't get all of them. Now it is almost time to bring the plants in for winter and I am afraid that will only make it worse.

Patricia

Oh my Patricia, I'm so sorry! That sure sounds like a lot of work to me. I hate it that you're seeing them again.

These things are absolutely the worst I've ever seen. I've had them since spring and they got REALLY bad! Here is a great recipe that I've had wonderful luck with. I still see a few....but I blast them as soon as I see them. LOL

The recipe is from TARogers....at the bottom of the thread.
http://davesgarden.com/forums/t/634736/#new

I am still blasting them when I see them with straight alcohol. They must be down in the rocks. I know that I find them throughout my garden even in the soil outside. I am not sure what to do about that. I am always so careful not to bring anything into the greenhouse before dipping it and spraying.

I will check out the recipe, thank you for sharing it with me.

I will add that I got some of the "horticultural glue." Tanglefoot is the brand I bought. It is very helpful for the plants with longer stems or trunks. Tanglefoot is made from tree resins, castor oil, and vegetable waxes. It is a super sticky substance that prevents the crawling pests (and the ants that "farm" them) from moving up into the plant. I bought the "barrier kit" that the company offers. This includes a set of foam bands which you wrap around the tree and to which you apply the product, so that you don't have to apply it directly to the bark or stem. However, I don't use this banding material. I have been using masking tape instead, much easier, cheaper, and less visually distracting. As an experiment, I have applied the Tanglefoot directly to the stems of some herbaceous plants with no ill effect so far. I also applied it directly to the bark of one of my trees with no ill effect...we'll see.

Tanglefoot has another application for flying insects, BTW. I have heard of smearing the product onto yellow paper plates to make sticky traps for whiteflies, etc. I plan on trying that this year as well.

Hi, Patricia! It takes about two weeks for the Bayer's to take effect, but it WILL kill them for a whole year, as well as any other 'stationary' insect such as scale. I LOVE this stuff. For spider mites I use Neem light horticulural oil - works like a magic wand. Why not try the Neem for your mealies, too - it will suffocate those little buggers, and DON'T forget to spray the soil and greenhouse floor and walls, too.

Kay, I don't have any trouble killing the mealy's when I see them, but after a few day's there are more. Like I posted, I took every plant out of the greenhouse dipped and soaked very pot and plant in the bayers tree and shrub then dumped them pails through the rocks in the greenhouse floor. I didn't see any at all for a couple weeks, but then they have started to appear again. The only thing I can think of is the those maybe under the rocks didn't get hit with it very well. I even sprayed down the walls of the greenhouse, the tables tops, bottoms and sides. I am just desperate to get rid of these before I move the brugs. in there for winter.

Jerodsmom, I would go ahead and treat your brugs with the systemic now, before you take them in the GH. I haven't found that the Bayer works for a whole year, but it works for weeks to months, anyway. Be persistent and keep after them.

SB

Thank you all for your support, I will just keep plugging away at it.

Jerodsmom, just dropped into this thread and can sympathize, as I've had such terrible problems this year with aphids and whiteflies.

I too have a dirt/gravel floor, and my plan is that once the greenhouse is cleared of plants I will spray the floor with something really nasty and immediately cover it with plastic, so that the fumes will stay down there. Haven't decided on the murder weapon yet!

We're going away for most of October, so I'll leave the greenhouse closed up until our return and hope that things will have settled down.

I don't have to worry about our water table being polluted, luckily, but that could be a problem in some areas.

Rosemary

I have found that I have mealy bugs all over my yard on the plants and in the soil. Almost everywhere I dig in the yard I see the white fluffy stuff. I am not sure what I am going to be able to do about it.

I sure hope your plan works for you.

Patricia

Hi all! I just found this thread too. I brought a citrus tree into my greenhouse about 5 years ago that had
mealybugs. They spread everywhere. Initially I tried washing them off with water. This didn't work. Then I
used Neem Oil spray - it helped but no where nearly well enough. Then I tried a pyrethrum based spray I
got from Charlies Greenhouse - its time released. It worked a lot better. I took everything out of the greenhouse,
washed down EVERY surface with dilute chlorine bleach, including walls and floor. Then I used the
Bayers Tree & Shrub systemic on the citrus & hibiscus (the plants that always had the mealybugs come back)
and sprayed with that pyrethrum time-release everywhere. I have not seen a mealy bug since (I did this
late winter so maybe 6-7mo. ago).

Good luck! Those mealybugs are why I gave up on hoyas years ago.

Tam

Almost forgot - a huge benefit in the battle was setting up fans that run continuously over my
benches. Seems to help a lot with the bugs and fungal issues.

I do run fan's in the greenhouse too.