Over the past months, I've noticed a lot of black leaf mold on my ornamental and fruit trees. Can anyone tell me something about why it's happening, and how to get rid of it?  Thanks much.

I think you find it is aphids ,a photograph would help .

How to get rid of them ,you could use a chemical method ,or a more natural method,ie Neem Oil.

Go back a page on this forum ,to Bactericide and Fungicide for trees thread  I think you will find the answer there.

3 hours ago, kickstart said:

I think you find it is aphids ,a photograph would help .

How to get rid of them ,you could use a chemical method ,or a more natural method,ie Neem Oil.

Go back a page on this forum ,to Bactericide and Fungicide for trees thread  I think you will find the answer there.

Thanks, kickstart.  I'll check the thread you mention.  I'll try to add a photo tomorrow.

Usually aphids, mould forms on their excrement. If you have ants around, then I'm pretty sure.

OK, I guess I was expecting a lot for anyone to diagnose the problem(s) without at least a photo or two.  As for ants, there are some, as usual in these parts, but I do spray for ants regularly, and for the most part, there aren't many to be seen on the vegetation...if any at all.

 

I've been renting this property for the past 7 years, so I've not been too concerned about keeping the plants in the healthiest condition.  Moreover, the problem of black leaves hasn't been too bad until lately. 

 

Here's what I'm dealing with.  I don't even know the names of some of these plants.  The last three are Jasmine, Lamyai, and Mango.

I see possible aphids, thrips, whitefly, sooty mold, micro-nutrient deficiency.

  

"I've not been too concerned about keeping the plants in the healthiest condition."

This is a key statement and the primary reason for the pest problems, not lack of spraying pesticides. Without good soil fertility and water management, the plants become highly susceptible to pest infestations. 

It's classic situation that can be applied to all sorts of activities.

Didn't look after the plant > nutrient deficiencies.

Nutrient deficiency (probably iron) > a weak plant.

Weak plant > open to attack by insects.

Aphids leave their excrement and mould develops.

Anyway. Try to find a liquid fertiliser containing micro elements including iron and magnesium. Blood meal is a cheap substitute. Also, maybe your land was heavily compacted by machines before planting?

Don't expect quick results.

Meanwhile, spray with Neem oil or Wood vinegar to get rid of the pests.

 

Seeing as how I'm renting this home, I don't have any idea about its history, nor do I care to get too involved in major soil improvement.  But I will take your suggestion and spray with Neem oil or other products that have been mentioned. 

 

Thanks all for your good advice.