Leaf symptoms

Symptom

Possible cause

Healthy leaf (left) vs. diseased leaf with distinctive mottled yellowing (right) (© Dagmar Hanold and John Randles, Waite Agricultural Research Institute)

Cadang-cadang (CCCVd)

Sooty mould growth from honeydew secretions, surrounding woolly insect colonies at the base of a frond (© Lyle J. Buss, University of Florida)

Cocoa mealybug

Pineapple mealybug

Striped mealybug

Coconut mealybug

Sooty mould growth from surrounding woolly insect colonies and honeydew secretions (© Lyle J. Buss, University of Florida)

Cocoa mealybug

Pineapple mealybug

Striped mealybug

Coconut mealybug

Caterpillar feeding resulting in light grey lines or "windows" with exposed leaf skeleton (© PestNet)

Coconut flat moth 

Additional symptoms of coconut flat moth include: 

• Leaves that have separated away from the midrib.
• Damage to middle aged leaves that has progressed to older leaves.
• Unhealthy and dry leaves.
• Death of damaged palms.
• Possible nut reduction in mature palms and reduced seedling growth.

Leaflets showing brown, burnt looking decay (© PestNet)

Coconut hispine beetle

Additional symptoms of coconut hispine beetle include: 

• Red-brown narrow strips of feeding damage on the unopened spear leaf, parallel to the midrib.
• Enlarged strips or streaks when the leaf unfolds that look blotchy and grey-brown.
• Malayan Dwarf varieties are showing severe symptoms compared to others.

Brown narrow furrows along leaves. Adult beetles may be seen feeding and leaving the furrows behind (© Jean-Pierre Labouisse, CIRAD)

Coconut leaf miner

Additional symptoms of coconut leaf miner include: 

• Damage to the three to four youngest leaves first.
• Mines from the base of the leaf, parallel to the midrib.
• Feeding damage that has a burnt or decayed appearance.
• Decayed and weak leaflets, eventually curling over and dying.
• Weakened fronds may appear ragged due to tearing and breaking in the wind.
• In severe cases, palms within one plantation may all turn brown.
• Early nut fall and reduced flower production.
• Symptoms appearing after droughts.

Damage on leaves that is brown to grey and appears burnt or decayed (© Jean-Pierre Labouisse, CIRAD)

Coconut leaf miner

Additional symptoms of coconut leaf miner include: 

• Damage to the three to four youngest leaves first.
• Narrow furrows along a third to half of the leaflet from the tip.
• Mines from the base of the leaf, parallel to the midrib.
• Decayed and weak leaflets, eventually curling over and dying.
• Weakened fronds may appear ragged due to tearing and breaking in the wind.
• In severe cases, palms within one plantation may all turn brown.
• Early nut fall and reduced flower production.
• Symptoms appearing after droughts.

Bored holes at the base of the fronds (© Pacific Biosecurity)

Coconut rhinoceros beetle - Oryctes rhinoceros

Additional symptoms of coconut rhinoceros beetle include: 

• Boring in young fronds that are yet to open.
• V or wedge shaped sections of the leaf missing.
• Excreted plant tissue and frass at the entrance of bored holes.
• Palms of a young age of 1-3 years more severely affected.
• Healthy palms older than 1-3 years, mature and tall (20-30 m), flower or fruit bearing, may have reduced strength and growth of the crown.
• Secondary infections visible at the bored holes.

V shaped feeding damage on fronds (© Pacific Biosecurity)

Coconut rhinoceros beetle - Oryctes rhinoceros

Additional symptoms of coconut rhinoceros beetle include: 

• Boring in young fronds that are yet to open.
• Bored holes in the base of the frond midrib (10-50 cm from the base).
• Excreted plant tissue and frass at the entrance of bored holes.
• Palms of a young age of 1-3 years more severely affected.
• Healthy palms older than 1-3 years, mature and tall (20-30 m), flower or fruit bearing, may have reduced strength and growth of the crown.
• Secondary infections visible at the bored holes.

Palm frond leaflets look squeezed and crushed together while the fronds show twisting, nicks and truncation (© Department of Agriculture and Water Resources, Australia)

Melanesian coconut rhinoceros beetle

Additional symptoms of Melanesian coconut rhinoceros beetle  include: 

• Bored holes into the frond growing point with excreted material.
• Fronds with wedge or V-shaped patterns.
• Fruit may have exit damage from the beetle.
• Young palms up to 5 years old showing more damage.
• Bored holes may have other pest insects (termites and weevils) inside.

Yellow spots concentrated on an area of a leaf. Note the brown spots starting to appear (© TNAU)

A leaf with a crusted surface. A closer look may show a heavy yellow-orange scale insect colony (© TNAU)

Leaf tissues looking yellowed or brown and wilted, especially near the tip of the frond (© Merle Shepard and Gerald Carner, Clemson University)

Yellowing and following death of leaflets from the tip of the diseased frond (© Geoff Gurr, Charles Sturt University)

Malayan Dwarf variety showing red-greyish brown leaves throughout green healthy leaves (© Nigel A. Harrison, University of Florida)

Lethal yellowing

Additional symptoms of lethal yellowing include: 

• Blackening and rotting of the inflorescences (flower clusters). 
• Fronds die and hang down.
• Death of the emerging spear leaf. 
• Death of the growing point of the palm occurs next.
• The crown falls, leaving a dead trunk only, sticking up like a telegraph pole.

Yellow splotches on leaves that may have turned brown and yellowing of the midrib (© Jorge Peña, University of Florida)

Straight edged of leaves rather than pointed tips (© International Palm Society)

Palm weevil

Additional symptoms of palm weevil include: 

• Chewed holes or tunnelling with ejected material and possibly brown liquid at the entrance on frond bases and stem.
• Crunching and chewing sounds when in close range to the trunk.
• Hollowed out palm trunk.
• Wilted crown.
• Death of fronds.
• Eventual collapse of palm.