The pest population is active throughout the year, with the highest numbers typically occurring from June to September, which coincides with the onset of the monsoon season.
Symptoms of Damage
1.Yellow patches on leaves
2.Oozing of the gummy exudation
3.Brown colour patches on nuts
The earliest symptom on 2–3 month-old buttons is the appearance of paleyellow triangular patches below the perianth. These patches later turn brown. Severely affected buttons may fall off prematurely. As the buttons mature, brown patches develop into black necrotic lesions with longitudinal fissures on the husk. Oozing of gummy exudation can be observed from the affected surface of the nuts. Uneven growth results in distortion and stunting of nuts, leading to a reduction in copra yield. In severe cases, the nuts may be malformed with cracks and hardened husks.
Identification of the Pest
Mites are typically found under the bracts of fertilized female flowers and do not infest unfertilized flowers.
These mites are very small, measuring 200–250 microns in length and 36–52 microns in width, with two pairs of legs.
Both nymphs and adults are pale in color, with elongated bodies and a worm-like appearance.
The life cycle of this mite includes eggs, two larval instars, and an adult stage, completing in 7-10 days.
Management
Cultural Method
Collect and destroy all fallen buttons from affected palms to prevent further spread. Grow intercrops such as sun hemp (four crops per year) and establish a shelter belt with casuarina around the coconut garden to prevent further infestation. Ensure adequate irrigation to maintain plant health and vigour.
Apply fertilizers: urea 1.3 kg, super phosphate 2.0 kg, and muriate of potash 3.5 kg per palm per year. Increased quantities are recommended to enhance plant resistance to the mites.
Apply micronutrients through soil application: Borax 50 g, gypsum 1.0 kg, manganese sulfate 0.5 kg per palm per year, or use TNAU Micronutrient solution 200 ml per tree.
Chemical Method:
Spot application of ecofriendly Botanicals
Round 1: Use Azadirachtin 1% (5 ml in one liter of water).
Round 2: Apply a mixture of Neem oil and Teepol (30 ml in one liter of water).
Alternating Treatments: Apply Triazophos 40 EC at 5 ml/liter or Carbosulfan 25 EC at 2 ml/liter, alternating with Neem Azal 1% at 5 ml/liter as spot applications.
Neem Cake Application: Apply Neem cake at 5 kg per palm per year for soil amendment and pest control.
Preparation of neem oil + garlic emulsion (2%):
To prepare 10 liters of 2% neem oil + garlic emulsion, follow these steps:
First, gather the ingredients: 200 ml of neem oil, 200 g of garlic, and 50 g of ordinary bar soap. Start by preparing the soap solution. Slice the ordinary bar soap and dissolve it in 500 ml of lukewarm water, stirring until the soap completely dissolves. Next, prepare the garlic extract by grinding 200 g of garlic and mixing the resulting paste with 300 ml of water. Allow the mixture to sit for a while to extract the garlic essence. Then, make the emulsion by slowly pouring the 500 ml soap solution into 200 ml of neem oil, stirring vigorously to achieve a thorough emulsion. Afterward, mix the garlic extract into the neem oil and soap emulsion. Finally, dilute 1 liter of the prepared stock solution with 9 liters of water to obtain 10 liters of 2% neem oil + garlic emulsion. Ensure thorough mixing at each step to achieve a uniform emulsion. This preparation can be used as a natural pesticide and repellent in agricultural applications.
Method of Application
To apply the botanicals (neem oil + garlic emulsion) as indicated:
Sequence and Interval:
Apply Azadirachtin 1% (5 ml in 1 liter of water) first.
After 45 days, apply Neem oil + Teepol (30 ml in 1 liter of water).
Alternate between Triazophos 40 EC (5 ml/liter) or Carbosulfan 25 EC (2 ml/liter) with Neem azal 1% (5 ml/liter) as spot applications.
Application Method:
Use a 1-liter hand sprayer for application.
For small trees, a rocker or pedal sprayer can be used effectively.
Target Area:
Apply the spray to the crown region of the coconut palm.
Ensure coverage of the top six bunches, especially during the non-rainy season to optimize effectiveness.
Following these guidelines helps in effectively managing pests and ensuring the health of the coconut palms.
Precautions and Safety Measures
To ensure safe and effective application of the botanical sprays (neem oil + garlic emulsion) and other pesticides:
Avoid Spraying in Windy Conditions:
Spraying should be conducted during calm weather to prevent drift and contamination of unintended areas.
Use Protective Gear:
Wear protective clothing such as long sleeves, pants, gloves, and a face mask to prevent direct contact with the spray.
Post-Spraying Hygiene:
After spraying, wash your face and hands thoroughly with soap and water to remove any residues from your skin.
Following these precautions will help in minimizing exposure to pesticides and ensure safe handling during the application process.
Biological Method:
Using entomopathogenic fungi like Hirsutella thompsonii and Verticillium lecanii is indeed a promising approach for managing mite infestations. These fungi are known for their ability to infect and control pest populations effectively. Here are some key points
About their application:
Commercial Availability: Both Hirsutella thompsonii and Verticillium lecanii are commercially produced by firms specializing in biological control agents. They are typically sold as formulated products ready for application.
Application: These fungi are applied as biopesticides. They can be sprayed directly onto the affected plants or areas where mites are prevalent. The fungi infect the mites upon contact, leading to their control over time.
Effectiveness: Research and field trials have shown that these fungi can effectively reduce mite populations when used according to recommended practices. They are considered safe for beneficial insects and the environment.
Integration: Integrated pest management (IPM) strategies often incorporate biological control agents like entomopathogenic fungi alongside cultural and chemical methods to manage pest populations sustainably.
Commercial Use: Farmers and growers interested in using these fungi should consult with agricultural extension services or suppliers to ensure proper application methods and timing for their specific crops and pest situations.
Using Hirsutella thompsonii and Verticillium lecanii can be part of a comprehensive strategy to manage mite infestations while minimizing environmental impact and promoting sustainable agricultural practices.
