Potato leafminer fly: potato pest in Indonesia

Page last updated: Friday, 3 July 2020 - 3:02pm

Please note: This content may be out of date and is currently under review.

Potato leafminer fly is a major pest of potatoes in Indonesia but does not occur in Western Australia.

The Department of Primary Industries and Regional Development has worked with the Indonesian potato industry to increase the productivity of Indonesian crops planted with WA seed potatoes.

Improved productivity requires accurate identification of pests in potatoes as well as in the cabbage rotation crop.

As well as helping Indonesian farmers this information will assist Western Australian seed potato exporters understand the challenges their Indonesian customers face.

Identification

The potato leafminer fly’s Indonesian name is "lalat pengorok daun" and its scientific name is Liriomyza huidobrensis.

Potato leafminer flies are only about 2 mm long, but are distinctive with their shiny black body and two yellow spots on their back
Adult potato leafminer fly

This small fly is only 2–3mm long but is quite distinctive with a shiny black body and two yellow spots on their side and one on its back. They arrive in crops in swarms, usually in the early growth stages. They fly or run off quickly when disturbed.

Spots on potato leaves caused by potato leafminer fly adults feeding and laying eggs
Spots on potato leaves from potato leafminer fly adults

Adult potato leafminer flies feed on potato leaves which results in spotting but does not cause any damage. In humid and moist conditions this feeding could make leaves more susceptible to disease infection.

Leafminer fly adults inject their eggs into potato leaves. Feeding and egg laying by adult flies appear as white specks on potato leaves. These white leaf specks are seen easily with the naked eye and are a good indication that a potato crop is infested with potato leafminer fly.

Multiple mines on a potato leaf caused by maggots of potato leafminer fly
Potato leafminer fly mines in a potato leaf
Maggot of potato leafminer fly exposed from a mine within a potato leaf
Maggot of potato leafminer fly

Eggs hatch into maggots which feed within the leaves, producing wiggly mines. Many maggots and their mines can be present on a single leaf. 

Feeding by maggots causes damage because they kill leaves, preventing the plants from producing large tubers. Leafminer fly maggots do not have a pink area behind their head like potato tuber moth larvae. Also, there is usually only one mine per leaf when leaves are infested with potato tuber moth larvae.

Contact information

Stewart Learmonth
+61 (0)8 9777 0167