Hope you all had a great new year weekend.
Few weeks back, I posted a topic in the forum to build a database of pictures of various pests. The main idea was to make it easier for novice gardeners to identify the pest they are having without much difficulty. With that in mind, I started looking closely at my plants every single day; all the plants. I got plenty of insects. This inspired me to start this Plant Pests Series. Every post in this series will feature a pest. It will have the following about the pest
The star of this post is Leaf Miner. Leaf miner is a name given for the larval stage of many insects that consume the leaf tissue. Most of the leaf miner are larval stages of flies. While the adult is considered harmless, the larvae feed on the upper and lower surfaces of the leaves causing the wavy squiggly lines on the leaf surfaces
In case of leaf miner, the pest can only be identified after the damage is done. The symptom of leaf miner damage is the squiggly lines made by the maggot as it bores through the leaf tissue eating it away. The damage will look like the picture below. (The damage via alphabets in the image is done by me..insects are innocent!)
After several days of mining in the garden, I was able find a miner taking a walk in the park, munching along..The dark lines are its poop.
This is up close with the maggot. The damage to the leaf is very clear in the picture below. The larva has eater away the leaf tissue and only the surface epidermis remains.
Leaf miner attack can cause serious damage based on the density of the insects and the stage of the plants. Seedlings affected by leaf miner show stunted growth and might die but it is not very common. Plants with heavy foliage can handle some amount of leaf miner damage without any noticeable impact in yield. But heavy infestation can seriously reduce the yield.
This is how the story of a leaf miner goes..
- Mature larvae in soil/host plants wait for the conducing weather. As the warm weather sets in, they go into pupal stage and turn into adults.
- Females after mating, search for leaves in order to lay the eggs.
- Females have a needle like organ which aides them to pierce the leaf and lay upto 200 eggs into the leaf tissue…under the surface.
- From then, all it takes is couple of weeks for the eggs to start drawing lines in the leaves.
- After 3 weeks, they become mature and is all set to go into pupal stage..
- See Step 1.
Leaf miner Control
Usually leaf miners have lots of natural enemies that consume them. The outbreak of leaf miner might arise after a use of insecticides that kills its enemies too. The safest control is to simply remove the affected leaves and dispose them off.
Neem oil is an excellent pesticide to control leaf miners. 30ml of neem oil in a litre of water along with little dish soap can be used as a spray.
Alternatively, one can use yellow sticky traps to attract these flies and destroy them.
Insecticides like permethrin, bifenthrin and deltamethrin can be used to control adults. Since these are contact insecticides the larvae inside the plants are still not affected.
To control the larvae systemic insecticides like Imidacloprid can be applied. Dosage of these insecticide are as per the instructions on the label.
That’s all in this post.