Question
QUESTION: Hi David,

on "white calandiva" leave, bought a month ago, appears black spot slowly though I have cut away the bad leaves. Do you know what is this black spot ? Fungus ? How to cure ?

The "orange calandiva" has white scar on several leaves, surely not insects but scar, what is this and is it dangerous ?

If you have email address, I can send some pictures.

Rgds,

Ari

ANSWER: Please do send pictures to [email protected].  Sounds like maybe a bacterial disease or it could be too hot or too much sun.  Lets see what the pictures show me.  Thanks.

---------- FOLLOW-UP ----------

QUESTION: Hi David,

already sent the pictures to your email address.

Calandiva White
I'm pretty much sure it wasn't too much sun because I put under house roof (indirect sunlight) and the condition was not very healthy when I first bought it but no choice because no other option.

File: Calandiva White 01_02_03 = condition 2 weeks earlier, some flowers fail to bloom, small holes on leaves, stem wilting, leaves deformation (not seen in picture). I think no mistake in watering (once a week) and no mistake in pot soil (porous soil).

File: Black Spot = current condition. Cut off all the flowers, cut off the wilting stem, eliminate bad leaves with black spot already, but still unfortunately today the black spot is there.

If it is bacterial or fungus or virus disease can it still be salvaged ? How ? Or do I have to throw it away before it infects other Calandivas ?

Calandiva Orange
This one is a lot healthier than the white one, but I found white scar on 2-3 leaves and small brown spot on back leave (see left leave in picture). I hope this is not so dangerous and could still be cured compared to white calandiva condition.

Rgds,

Ari  

Answer
The plant with the marks on the stem appear to be insect damage.  Slugs will feed at night and you will not see them.  If inside the house, there could still be some bug in the soil that has fed on the stem.  I would treat all plants with malathion.  Do this outside and leave outside overnight, then bring back inside or place in an indirect sunlight environment.  The white spots and black spots on leaves look like a disease.  I would pull these leaves off and destroy them.  You can treat with the Cornell Fungicide which you make at home.  Mix one tablespoon baking soda and one tablespoon light cooking oil in a gallon of water and spray plants every 3-4 days for about three times.  This should prevent further infection. Otherwise the plants dont look that bad to me.  Good Luck.