Coconut palms, also known as 'Kalpavriksha' are super important in India because they provide food, homes, and jobs for lots of farmers, especially along the east and west coasts.
But there's a problem: a tiny bug called the eriophyid mite is causing big trouble for coconut trees. This bug, known as Aceria (Eriophyes) guerreronis Keifer, was first spotted in Kerala. Then, it quickly spread to other states like Tamil Nadu and Karnataka, making life hard for farmers everywhere.
To tackle this issue, many organisations joined forces to find a better way to manage these pests. The Government of India even set up a special committee to monitor the research and help farmers deal with the problem.
It's pretty rare to see so many groups working together like this, but it's been a big help in understanding and fighting the mite problem.
The A. Guerreronis, in India and beyond
Back in 1998, researchers first spotted these mites on coconut palms in Ernakulam District, Kerala. Quickly, they found out that these bugs were pretty much everywhere in nearby districts of Central and South Kerala. Then, in the same year, scientists in Tamil Nadu discovered them in Coimbatore District, and soon after, they were seen all over Karnataka.
After that, they popped up in other places, too. In 1999, they were found in the Chittoor area of Andhra Pradesh. Then, in 2001, Orissa saw them, followed by West Bengal and Maharashtra in 2002 and finally Gujarat in 2003.
But this bug's story didn't start in India. Nope, it actually began in Mexico back in 1965, when Keifer first reported it. Then, it spread to South America and some nearby islands. According to reports, it really started picking up pace between 1977 and 1984, spreading fast. Tanzania got hit in 1980, and Sri Lanka saw them around the same time India did, in 1997.
So, basically, these mites love warm places around the world, from South and North America to Africa and South Asia. They're like little travellers, always popping up where it's nice and tropical.
Bioecology of the Mite
When coconut nuts are developing, that's when the mites sneak in. They come in right after pollination, and the lady mites lay eggs inside the nuts, forming colonies. These colonies have different stages of mites - eggs, young ones (called nymphs), and adults. It takes about 7 to 10 days for these mites to go from egg to adult.
These mites are super tiny, only about 200-250 microns in size. They have a funny shape with two parts: a front part and a back part. Their bodies have little bristles all over, and they're kind of pale yellow. They have two pairs of legs at the front, and their mouths are perfect for sucking plant sap.
You can find these mites in coconut flowers and the soft part right under the outer covering. They start causing trouble right after pollination. First, you might notice long white streaks under the outer covering. Then, these streaks turn into yellow patches. The mites suck the sap out of the coconut, which makes the affected part dry up and turn brown.
As the nuts grow, they might get warts or cracks on the surface. If the infestation is bad, the nuts might dry up and fall off or grow funny because of stunted growth. This can lead to less coconut meat and messed-up coconut fibres, which is a big loss for farmers.
Crop Loss
When the pesky bugs infest crops, they can cause a lot of damage. In India, in 1998, these pests affected about 85-90 per cent of coconut nuts, leading to weird-shaped and smaller nuts. However, as time passed, there was some relief as the number of pests decreased in the areas where they first appeared. In one district called Alappuzha, a study in 2000 found that farmers lost about 31 per cent of their copra (the dried meat of the coconut) and 42 per cent of husk production due to these bugs.
In Tamil Nadu, another study estimated a 27.5 per cent loss in copra yield. When the infestation was severe, with more than half of the nuts affected, copra yield dropped by 18-42 per cent. These pests didn't just affect the number of coconuts but also the quality of the fibre they produced, making it shorter and weaker by up to 53 per cent in severely infested nuts.
Managing Coconut Mites
Various methods have been explored to control their population when dealing with coconut mites. However, implementing effective management strategies can be challenging due to the resilient nature of these pests and their protective habitat.
Chemical Solutions
In efforts to swiftly tackle the issue, pesticides have been extensively tested worldwide. Techniques such as spraying affected areas, stem injection, and root feeding with systemic chemicals have been experimented with. Studies have shown promising results with pesticides like dicrotophos, monocrotophos, and acaricides applied at specific intervals. In India, numerous pesticides have been trialled, showcasing reductions in mite populations through methods such as root feeding and spraying.
Eco-Friendly Alternatives
Scientists know they need to find ways to help the environment, so they've been looking into eco-friendly options like wettable sulfur and fish oil resin soap (FOIS). Although wettable sulfur worked well in tests outside, using it a lot could hurt the plants that naturally grow in an area. When sprayed at appropriate intervals, FOIS also showed promise in managing mite populations. Additionally, unconventional methods like smoking in gardens and spraying substances like starch or seawater have been attempted with varying degrees of success.
Biological Control
Given chemical applications' limitations and labour-intensive nature, biological control methods are gaining traction. Biocontrol offers a safer and eco-friendly approach to pest management, which is crucial for sustainable solutions. While no parasitoids have been reported on coconut mites, predators play a significant role. In different places, we've noticed that certain bugs and mites eat coconut mites, showing that using natural predators could help control mite problems.
Conclusion
Eriophyid mites mess up the coconuts, making them grow funny and ruining the coconut meat inside. This is causing big trouble for farmers who rely on coconuts for their livelihoods.
To deal with this, lots of different groups are working together to find ways to fight these bugs. It's tough because these mites are super small and good at hiding, but people are trying their best to protect the coconut trees. It's important because coconut trees give us food, homes, and jobs, so we need to make sure they stay healthy.
