Looks like one of the cottony scale insects, to me. It appears that the egg sacs have discharged the newest generation.

Where is this plant ( inside or outside)?

The plant is outside. It seems like it is spreading to my other patio plants.

I recommend a horticultural oil to solve the pest problem. Oils work by physically coating the critter and/or its eggs rather than by chemical means. Scale insects, in particular, are effectively controlled by oil applications.

There are many commercially available options for you to select from. If you tell me what kinds of plants you have and your general location, I will be happy to help you with safe and effective treatments. Some plants, you see, are sensitive to oils and can be damaged. Also, there are temperature restrictions.

Please go to your profile and put in your location. We don't know if you are in Canada, South Africa, India, etc. Your location is very very important to getting any good advise.

mleonmd lives in the US, stated in his/her member page. Judging by the fact that this is a tropical plant living outside, it's pretty safe to deduce that the poster is from one of the subtropical areas.

Though it is hugely helpful, in most cases, to know the general location of a person.....not so much in this case. :-)

Google mealybug for information on these nasties.

If the infestation isn't too bad (and you have the time) a q-tip dipped in rubbing alcohol and applied to them will work.

If the mandevillea is large and the mealybugs are throughout, I would resort to a systemic. Their waxy coating can be impervious to sprays unless a wetting agent is used.

These don't appear to be mealybugs.

rhizo_1, no offense but you are making too many assumptions. The OP didn't say it was grown outside, you assumed that. They may have an indoor growing setup. They may be 10 miles from the Canadian border for all we know. I do believe locations are extremely important to get accurate responses.

Well, since the plant is outdoors -- the OP said so -- likely s/he lives in a warm climate.

Did you not read the whole thing?

" Posted by mleonmd none (My Page) on
Tue, Jan 21, 14 at 15:31

The plant is outside. It seems like it is spreading to my other patio plants."

I really appreciate all the comments. My location IS posted on my page. I live in Tampa, Florida. It is 5/5a zone. So far I tried two of the commercially available agents ( home depo) Natria by Bayer and Spectricide immunox. It helped only temporarily and some white spots never went away.
Can I use oil agent on my plants?

Your zone should be 9 in Tampa. You can check it by entering your ZIP code in the zone finder.

If the white spots are empty egg sacs, they would not go away by using/applying a chemical, and have no effect on plants at this point. New leaves should be free of damage if the product you used killed the pests.

I'm sure someone will answer the question about oil soon, IDK.

Tsk tsk, mleon. Why would you use a broad spectrum fungicide for an insect infestation? It's never a good idea to apply harsh chemicals unless you know exactly what its for. That would be like prescribing heavy duty pharmaceuticals for a patient complaining of headaches....when she just needs her glasses adjusted.

Please let me know which Natria product you've used. The label will clearly list the Active Ingredients on the very front of the container under the heading : Active Ingredients.

The Natria products that I quickly looked at are oil based, one canola and one neem based. They would be examples of the horticultural oils I mentioned to you a week ago.

In Tampa, USDA climate zone 9 to 9b, you should be able to safely use the oil spray during the winter as long as temperatures don't go below or above what is probably cited on the label.

I implore you to avail yourself of that label information. I always tell people to read, understand, and follow the directions BEFORE using a chemical product.

Those empty egg sacs suggest to me that the hundreds of eggs have hatched and the babes are wandering at large. All the more reason to use a horticultural oil several times throughout the year, weather permitting.

If you do a tiny bit of research regarding horticultural oils in general, you will hopefully appreciate how useful they are. There are many different oils which are used in this manner.

This post was edited by rhizo_1 on Tue, Jan 28, 14 at 14:02

Mieonmd,

I bought Natria by Bayer to rid some primroses of spider mites. Followed directions and since they were potted it was easy to spray the undersides of the leaves. Did not help a bit after 3 applications. New growth still becoming infected. I will save the Natria in case of a mealybug infestation, as they are listed on label. But I'm not holding my breath. To get rid of the unsightly empty white casings of mealybug use a soft toothbrush or your fingers if you're not squeamish.

The Spectricide immunox controls fungi like: anthracnose; black spot; blight; leaf smut; leaf spot; powdery mildew; rust and others. It will not affect our common pests like aphids and mealybugs. I haven't seen fungi on mandevilleas here (mild winters). Mealybugs and aphids seem to be their chief nuisance.

Application of horticulture oil is recommened for temps. between 40 F. to 90 F. and humidity between 45 to 65%. Always check the label as there are different types of oil.

Hope your mandevillea is better.