Tanglefoot, a control for coffee green scales

By YVONNE NGUTLICK of CIC

The name sounds quirky but Tanglefoot may be the answer to coffee farmers’ woes against the coffee green scale pest.

Coffee green scales

Tanglefoot is a jelly-like substance that stops the movement of ants up and down coffee trees.

It is non-poisonous to ants, other organisms and humans.

Pasting Tanglefoot on the tree stump near the base effectively prevents the ants from climbing up and down the tree accessing aerial parts of the crop.

Applying tanglefoot to coffee tree stump to prevent ants climbing

Coffee green scales are currently the most-serious pest affecting the coffee industry in Papua New Guinea.

They are soft scale insects.

They are oval-shaped, flat and pale green in colour.

Green scales are often associated with ants and ‘sooty mould’ fungus.

The ants and fungus feed on the honeydew excreted by the scales.

The scales suck the sap of mature and young coffee trees, reducing growth and eventually causing the death of the tree.

The presence of ants also provides protection for the scales from their natural enemies, like ladybird beetles and parasitic wasps.

Trials conducted at the Coffee Industry Corporation research station on using Tanglefoot in controlling green scales are encouraging.

The length of time to achieve complete control is three months.

 Control takes longer compared to recommended conventional methods of spraying and pruning that provide fast knockdown effect.

Tanglefoot, unlike conventional methods, poses no risks to the natural coffee environment and promotes sustainable control of the pest.

Following are important points to consider in order to attain such level of control:

• Tanglefoot needs to be adequately applied around the stump with 10-15 cm width and layer thick enough to avoid quick drying; and
• Arial canopy of the tree must be independently stand-alone. This means branches must not come in contact with branches of adjacent trees, particularly the infested trees, to avoid ant access from these trees.

Tanglefoot

Manufactured in the United States of America, Tanglefoot is not new in PNG, but new for the coffee industry. 

In the 1930s, Tanglefoot was trialed on coconut trees in Manus province to prevent coconut treehoppers. Climatological conditions in that coastal island province deteriorated the use of Tanglefoot but may prove otherwise for coffee, especially for farmers in the cooler Highlands provinces where green scales are rife.

Tanglefoot can be purchased from leading agricultural suppliers.