Onion pest and diseases can occur frequently but with proper care you can take care of your plant to ensure it thrives and is not susceptible to its pests like onion thrips, onion maggot, onion fly and onion diseases. Here, we have listed down the different pests, onion diseases and their control so you can be aware of them too.
Here is a list of onion insect pests that you should be aware of -
1] Onion fly
What is onion fly? - Onion flies usually hatch into maggots and tend to eat away at the seedlings at the leaf or the bulb of the plant. So it's very important to take care of seedlings. Also it’s a little hard to distinguish between a normal house fly and an onion fly as it seems much like the former.
Symptoms - This onion pest causes the plant to turn pale and wilt (after turning yellow) away due to which the bulb turns out to be rotten and smelly.
How to take care of onion flies - the rotten or damaged plants should be taken away and burnt to inhibit further growth. An insect-proof mesh can help protect against their attacks.
2] Lesser bulb fly
What is a lesser bulb fly? - With a similar life cycle as the onion fly, these pests can grow up to 5-9 mm in thickness and have a metallic bronze look but tend to appear black from a distance. They have white crescents on their abdomen areas with yellow coloured hair at their tips.
Symptoms - the bulb might be killed or damaged so only stunted growth takes place.
How to control lesser bulb flies? - You can use insect nets or sticky traps to prevent them from manifesting on your plant. The bulbs that have died or have been damaged should be removed from the rest of the plants and also, mowing at the basal leaves and cultivating them around the base area of the bulb of the plant can help the pests to grow in by filling in the holes.
3] Onion Thrips
What is an onion thrip? - Onion thrips are usually female and do not need their male counterparts in order to reproduce further. They lay their eggs onto the leaves of the onion plant which hatches in a period of 5-10 days.
Symptoms - The plants tend to turn into a silvery colour with blotches all around and deforned leaves.
How to onion thrips control? - spraying water from a gardening hose by positioning it right on top of the plant will cause the thrips to fall off the plant and keep them from coming back. A nitrogen based fertilizer sprayed towards the base of the plant and keeps on spraying till the growing season. Mulch will also help in taking care of thrips. Onion thrips insecticide control can also help in getting rid of them.
Common onion plant diseases that you should be aware of -
1] Leaf Blight
Botrytis leaf blight or blast as it is commonly known as spreads fast under moist conditions and leaves lesions on the bulb of the plant through the interior of the leaves.
Symptoms - it causes white spots on the leaves of the plant and kills the leaves causing damage to the whole plant as a whole which results in it wilting.
How to control Leaf Blight - Rotation of the crops for 2-3 years as well as use of organic fungicides can help control this disease. Planting them in a single row with sufficient gap (of at least 30-35cm each) can ensure air circulation.
2] Downy Mildew
This disease is fungal in nature and usually affects the younger plants. Wet leaves and cool temperatures are common conditions for its occurrence.
Symptoms - white mold on the leaves, leaves colour turns to yellow which causes the leaf to fall off, wilting.
How to control - non-allium rotation of crops for 3-4 years, remove damaged crops and their remains and spray foliar fungicides applying them especially on the waxy leaves.
3] Purple Blotch
Just like the name suggests, purple spots start to appear on the leaves when the conditions are pretty moist and in weathers that are hot and humid.
Symptoms - Small lesions that are water-soaked on the stalk or leaves of the plant that turn brownish to purplish to red in colour.
How to control - A proper drainage system that ensures the leaf remains dry and use of organic fungicides can prove to be beneficial.
Smut attacks when the seedlings are successfully germinated, however, it does not kill them. Even if they are taken care of, the onion plant either succumbs to another disease even if they are harvested.
Symptoms - These smuts are usually dark and cause the leaves to bend and also leave dark smudges on the young seedlings. The lesions tend to turn into black powdery substances that cause a stunted growth in the plant. This causes the plant to die in about 3 to 4 weeks. Smut can be prevalent in the soil for a long time.
How to control - avoid moving plants as well as plant remains across fields so they do not get introduced. A 3 year rotation can prove to be effective. Formaldehyde solution in the furrow area of the plant is also recommended.
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1] How do you protect plants from pests?
Spraying appropriate pesticides, incorporating plant rotations, and using insect nets are some good ways to control pests. Apart from that, building a healthy soil as well as making sure there is enough space between plants can prove to be beneficial.
2] How to store onion plants?
Store your plants in a cool and dry place that has a good amount of ventilation and way from direct sunlight.