Couch Grass Scale

Scientific Name:

Odonaspis ruthae

Order:

Hemiptera

How to identify Couch Grass Scale:

Couch grass scale is a small white or grey clam-shaped scale insect that appears as a smaller version of the adult when immature, generally less than 1mm in diameter.

• The adult is a larger, mollusc like scale insect with an armoured body up to 2mm in diameter.

• As they mature, the couch grass scale often turns cream to pink in colour. 

• Couch grass scale is usually found in congregations around the nodes and crown where they become easier to observe.

What is the biology and lifecycle of Couch Grass Scale?

Little is known about the lifecycle of this species, though it is thought to take 10-14 days for completion of the lifecycle from egg lay to maturity.

Damage to turf from Couch Grass Scale occurs from spring through to autumn as fluid is sucked from the turf plant as the scale insects feed underneath their shells. 

• Turf often turns yellow and exhibits symptoms of drought stress in patchy areas. When damage is severe the yellowing will often turn to brown and the foliage can die back. 

• Damage will occur most heavily in areas with an abundance of thatch. 

• Symptoms are most evident in drought conditions as pest feeding compromises plant moisture efficiency, and recovery is slowed due to a lack of water.

Couch Grass Scale can be managed or controlled by preventing excessive thatch accumulation from occurring. It is also important to ensure adequate soil moisture is available during periods of high pest pressure as it will reduce symptom expression and improve rate of recovery.

For chemical solutions and treatments for Couch Grass Scale, please see our recommended products below.