Leaf Miner Damage on Many Different Plants

Q. In my morning walk around the garden, I found this unusual pattern on the leaves of my Arabian Jasmine.  Do you have any thoughts on what might have caused this?

Serpentine leaf miner damage on Jasmine leaf.

A. This is one of the leaf miners. Because of its snakelike pattern of damage caused on the leaves, this particularly matter is called the "Serpentine" Leaf Miner. Leaf miners in general are the immature of moths or a flies but in this case of the Serpentine Leaf Miner the culprit is a fly. The fly's lifecycle has four stages; the adult fly with wings for finding a sex partner, the egg, maggot, pupa which finally turns into the adult again.

The serpentine leaf miner adult fly punctures the leaf surface. It inserts its eggs inside the leaf. This is a perfect warm and wet environment for the egg to hatch into a very tiny maggot. Food and moisture are all right there and protected from predators inside the leaf! This tiny maggot tunnels between the upper and lower surface of the leaf in this wet juicy nutrient rich layer where it feeds at the same time. 

Leaf miner attacking these leaves in Afghanistan

If you hold the leaf up to the light you will see that these serpentine patterns are tunnels, have nothing in them, but are surrounded by dark, green leaf tissue. The second thing you will see is that this serpentine tunnel gets wider along the feeding path and shows you the direction this maggot has moved inside the leaf; the tunnel is narrower when it is small and gets wider as it grows. At the end of this tunnel this maggot stops feeding and pupates into the adult fly and exits the leaf.

 

More leaf miner damage

To control this pastor not depends on the value of the damage it creates. Leaf miners also attack weekly green vegetables like lettuce and spinach. In cases like these, we don't want any damage or very little because we're going to eat these leaves. This insect is also causes damage to some fruit trees like citrus and ornamentals like roses, annual flowers and in your case Jasmine, where leaf damage can be tolerated more.

 

Leaf miner damage in citrus leaves

So the tolerant to damage of leafy greens is very low and start to control this pest in a variety of ways as soon as damage is seen. Control can be as simple as removing leaves as soon as you start seeing the damage. It takes a while for this past to create these tunnels so with a little bit of diligence, leaf removal works extremely well. Removing leaves as soon as you see damage reduces the level of adults and is very efficient at minimizing damage. When you remove the leaves, don't throw them on the ground but put them in the trash or destroy them immediately.

Heavy leaf miner damage. This damage is heavy enough that it might require spraying for prevention in the next planting.

You can spray the leaves with chemicals, and this is done frequently on leafy greens vegetables grown for commercial production to protect the crop, but if you don't need to spray then don't. Understand and live with the damage if it's minor and use leaf removal if it starts to get out of control.