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Lerps |
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Psyllidae - various spp.
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Lerp nymphs beneath scales (Psyllidae - various spp.)
? Agriculture Western Australia
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Description
The adult psyllid is about 4 mm long with transparent wings and a yellowish brown body. It is usually found in numbers on lerp infested leaves in summer. The lerp scale when fully formed in spring, is about 8 mm long, horn shaped and tapering from about 0.5 - 4 mm in width and is yellow to pale brown. Under each lerp scale there is an orange nymph which is active when the leaf is moved.
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Life cycle
The main lerp stage appears to be from May or June to November, development being slow during winter, accelerating through spring. Adults appear in summer when eggs are laid in batches of 50 - 100 on healthy leaf surfaces. The eggs are brown and less than 0.5 mm long. Heavy reinfestation does not usually occur until autumn when the summer leaf growth has replaced the foliage defoliated by the previous infestation. |
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Damage
The developing nymphal stages of lerps suck the sap of the leaves while sheltering under their "lerp" scales. In heavy infestations this eventually results in discoloration of the leaf which turns reddish brown and eventually dies and falls off. Severe defoliation may result from heavy infestations, and debilitation and death may follow repeated attacks. Flooded gum is the main host tree in riverine and farm sites and wandoo may also be infested in drought affected wheatbelt areas. River gums planted as a saltland rehabilitation species may also be heavily infested. Remnant areas off fat topped yate in swamps in southern areas can be severely affected. |
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Control
Incidence of wasp parasites appears to be very low in lerp infestations and their effect on populations is unknown. Birds may also feed on lerps but there is no evidence of them having a significant controlling effect. |
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