Eriophyid mites are translucent cigar-shaped microscopic mites that cause deformities to coconut fruits. They are noticed when their feeding causes abnormalities. The mite is usually found under the bracts of fertilized female flowers and does not infest the unfertilized flowers.

These mites are very minute in size measuring 200-250 micron in length and 36-52 micron in width with two pairs of legs. The nymph and adult are pale in colour with an elongated body and worm-like appearance. The life cycle of this mite consists of the egg, two larval instars and an adult stage and is completed in seven to 10 days. The mite resides under the sepals of developing nuts up to six months and feeds on the mesocarp.

Symptoms of damage
• Triangular pale or yellow patches close to perianth
• Necrotic tissue
• Brown colour patches, longitudinal fissures and splits on the husk
• Oozing of the gummy exudation from the affected surface
• Reduces size and copra content
• Malformed, smaller nuts with cracks and hardened husk

In severe cases, the nuts are malformed with cracks and hardened husk. The mites cause the nuts to be scarred but the water quality is unaffected. However, severely-scarred tender nuts may not find acceptance by consumers. These mites do not cause any damage to leaf tissue as with red palm mites (which would be discussed next week).

Management

Cultural control:
• All mature and prematurely- fallen nuts of the affected palm should be collected and destroyed
• Adequate irrigation and fertilization based on soil test should be provided to increase tolerance to the feeding and damage by the mite

Chemical control:
• Borax (50g)+gypsum (1.0kg) +Manganese sulphate (0.5kg) should be applied per palm annually
• Young bunches should be sprayed with five percent wettable sulpher
Spot application of ecofriendly botanicals:
• Azadirachtin one percent (5ml in 1 liter of water) + Teepol (30ml in 1 liter of water) should be alternated and applied to the crown region by a climber, covering only the top six bunches during the dry season.