I just added Mandevillas to my yard this season. I love how they are such avid climbers and the flowers a beautiful. However, in Southeast Texas this year we have had torrential rains and as these are certainly tropical plants I thought that they would not be affected much. Well, NOT............LOL. Believe it or not, they are the only plant I have in my yard that has seemingly suffered from all the rain. I initially thought that they had just stayed too wet, even though they are potted with good drainage.
The leaves started yellowing and eventually started showing dark brown to black spots. The rain has subsided for the most part so I left them to dry out a bit. They have just gotten worse, and one of them is really struggling to survive. By this time I had decided that what I was seeing was most likely some sort of a mold/mildew. My tomato crop was basically wiped out by all the rain, heat, sun, and humidity. This was the worst case of Early Blight I have ever had so I just assumed that some sort of systemic fungicide would be best. I have applied it several times over the last two weeks and things appear to be slowly getting better.
Please tell me if I am way out in "left field" or on the right track. I did read that Mandevillas are prone to red spider mites. It has been years since I have had to deal with those horrible things and never have seen them even in my vegetable garden. This really does look more like a fungal/mildew/mold issue. BTW, the leaves eventually completely die and go crispy brown and drop off.
I really hope someone can help me with this frustrating mess. The only good news is that my Plummerias are finally blooming..........YEAH!
Regards,
Tomatomaniac
P.S. I originally posted this under one of the Mandevilla postings above, but as it was an older posting perhaps someone might see it better here. Sorry about the double posting, but really would appreciate some help.................Thanks for looking!
I'm a noobie with Mandevillas.....What's happening ?
I think you're probably right about them getting too much water, yellowing leaves that die and fall off is a common symptom of overwatering. If the plants have started to improve then you're probably OK, but if the soil is still really wet, I'd repot them in some fresh soil, cut off any roots that look moldy, and then when you water it put in a bit of dilute peroxide or chamomile tea in the water, that will help kill the fungus. The systemic fungicide that you used will probably help a bit too, but if there's a lot of fungus in the soil still you're best off repotting.
With all the rain you had, it would be highly unlikely for it to be spider mites, they like low humidity and would not have enjoyed all the rain.
Thank everyone for your help with this new addition to my gardens. I really love this vining/climbing plant but it has really presented some challenges so far. If someone could take a look at this picture of what I had tried to describe perhaps you could see what I am concerned about. Thank you very much!
This is one more view of the affectations on this plant.
Any chance you can get larger pictures? Yours don't blow up very much when you click on the thumbnail so it's hard to see for sure what's going on.
I have been downsizing my photos for the sake of the forum's server and bandwidth.........Sorry. I'll resend them full size.
