Have you ever found a black part like dropping ink or tar on a leaf? This is it!
This is a disease called “sooty mold”. It is not limited to curry leaves, but it also spreads to leaves and stems of various plants as well as citrus fruits. The name comes from what looks like soot.
The direct cause is the secretion (excretion) of aphids and scale insects. The sooty mold (filamentous fungus) proliferates by using sugar contained in this excrement as a nutrient. When soot mold occurs, the photosynthesis of that part becomes difficult because the light that hits the leaf is blocked. As the disease spreads, the ability of the plant to photosynthesize significantly declines, causing damage to the plant.
Because it is a curry leaf used for food and treatment, it is not desirable to take measures using chemicals. Therefore, let’s remove physically. If it is a few leaves, remove them. If sooty mold has spread to a wide area, it is better to remove the whole branch. If you really want to use the chemicals, please try searching for the germicide for gardening.
Because the honeydew like secretion fluid of aphids and scale insects are on the front and back of the leaf, it is more effective to remove even the part where the secretion fluid is attached even if sooty mold has not occurred.
Measures the true cause of the sooty mold
Since the spread of soot disease is caused by the aphid and scale insect excrement, it is necessary to control these insects as another countermeasure.
Where there are a large number of scale insects, some people may seem quite shocking.
With regard to scale insects, an effective measure can be taken with one toothbrush. Specifically, please see the page of pests.
Prevent the occurrence of soot disease
Prevent the outbreak of aphids and scale insects, and take measures such as killing immediately when finding them. And, cultivating in a well-ventilated and sunny area is the point that makes sooty mold reduces risk to occur. Aphids and scale insects can also occur with over-fertilization. It is said that a large amount of nitrogen, which is one of the elements of fertilizer, is taken in, and insects that suck on the sap of amino acids synthesized in excess by nitrogen.
If sooty disease is confirmed in a plant planted in a nearby pot, separate the plant from other plants first.