Plum Crazy hibiscus malaise

I have been nursing a young "Plum Crazy" hibiscus for two years with measured success (it isn't dead yet). Please look at the latest symptoms: mottled yellow leaves, from spider mites presumably, and now also presenting with very dark, wilted edges on some leaves which are also curling in a bit. Could this be a chemical burn from horticultural oils that I have been using for the spider mites, or an unrelated problem? Has anyone had success with the temperamental "Plum Crazy" hybrid? Any tips?

Thanks,
BG, Orlando

You might want to consider a treatment with Imidacloprid where one treatment will eliminate insect problems all summer. This chemical is a nicotine analog and is used for flea prevention in cats and dogs.
http://en.wikipedia.org/wiki/Imidacloprid

There was a lengthy discussion on the use of Imidacloprid to treat whitefly infestation in Hibiscus mutabilis on this tread.
http://davesgarden.com/community/forums/t/546774/

Imidacloprid is used in several Bayer Advanced products and is sold at all Lowe’s stores. I am now using Imidacloprid on my entire Hibiscus collection including Plum Crazy as a long term prophylactic for insect control.

To do a low cost test to determine effectiveness of Imidacloprid try the spray bottle of Dual Action Rose & Flower Insect Killer which sells for about $5.00 at Lowe’s. Spray the leaves as directed but also apply some of the liquid to the roots as well. In addition to Imidacloprid, which is a long term insecticide, this spray contains a quick acting insecticide also. This treatment is only effective for 30 days.

Bayer Advanced Dual Action Rose & Flower Insect Killer
http://www.bayeradvanced.com/rose-flower-care/products/dual-action-rose-flower-insect-killer

If the spray bottle based product works, consider the used the liquid and pellet forms of the Imidacloprid sold by Bayer Advanced. This spring I am using both the liquid and pellet forms. The pellets are spread about the roots of Hibiscus growing outside and the liquid form is used to treat my indoor Hibiscus.

Bayer Advanced 12 Month Tree & Shrub Protect & Feed
http://www.bayeradvanced.com/tree-shrub-care/products/12-month-tree-shrub-protect-feed

Once I got my Hibiscus mutabilis through the winter and started moving them outside, in two cases way too early, I discovered that they were again infected with whitefly. I treated the H. mutabilis with the pellet Bayer Advanced 12 Month Tree & Shrub Protect & Feed and the whitefly was quickly eliminated. I again used the pellets when I did the final transplant into the garden. All of the Hibiscus in my garden, including Plum Crazy, appear to tolerate the Imidacloprid well. Buy the indoor spray form and give it a try. What I can not say with any degree of certainty is if Imidacloprid will work for your problem.

One word of caution. I am growing African Hibiscus from seeds; some of which can be used as a human food source. I would never recommend using Imidacloprid on any plant intended as a human or animal food source.

Please keep the DG forum update as to your results.

Mike

Thanks very much for the info. I have used Imidacloprid in the past on my brugmansias but did not know if my hibiscus plants would tolerate it. The Plum Crazy seems most affected by the pest, as my other hibiscus seem to be doing fine. I will try the Imidacloprid for the next few weeks and keep you posted on the results.

Best regards,
BG

If you're still having pest troubles then the imidacloprid's definitely worth trying--but it's possible that what you're seeing now is just residual damage. The mites suck on the leaves, and once they've damaged a leaf or part of a leaf to a certain point, that leaf/part of leaf is going to eventually turn brown and die even after the mites are gone. If the mites had time to do a reasonable amount of damage, the plant will often continue to look worse and worse in the week or two after you've gotten rid of them as all the parts of the leaves that they chewed on too much start to turn brown and die--it can make you feel like you haven't really gotten rid of the problem even though really you have but the full extent of the damage takes a little time to show up.

Thanks, ecrane3. I will keep your observations in mind and not grow disheartened that my Plum Crazy is looking quite the worse for wear....