PEST
 
   NAME
     Bean Fly
     Ophiomyia phaseoli
 
   ORDER
     Diptera
 
   FAMILY
     Agromyzidae

Description of the Pest
The small adult fly is black and up to 3mm long that lays eggs in the epidermal layer of the leaves causing small yellow spots. The tiny lava form tunnels in the leaf and down the petiole and in the stems of the host.
 
Adult Bean fly

Life Cycle
This insect has a Holometabolous life cycle, i.e. it has a larval and a pupal stage. The life cycle from egg to adult is quick and can be completed in less than two weeks. The fly pupates within the stem

Distribution of the Pest
It is normally found in tropical and sub tropical climates of Australia or Asia and is found throughout the year.

Period of Activity
Higher populations during humid weather in Spring and Autumn. It can be a pest all year round.

Damage Caused
The lava has chewing mouth parts and tunnels inside the stem or leaf petiole causing swelling in the stems which is accompanied by cracking lengthwise just above the soil level and appear reddish in colour. Infestation results in young plants wilting and collapsing and older plants produce poor quality fruit and are stunted. In cases of heavy infestation the plants die.

Susceptible Plants
French and climbing beans is the main host.

Control

Cultural Control
Difficult to control especially once the lava has tunnelled into the stem. Infected spotty leaves and heavily infested plants should be removed and destroyed.

Biological Control
There is no known biological control.

Chemical Control
The critical period is the first three to four weeks after germination. Weekly spraying of a systemic insecticide.
Note
It is your responsibility by law to read & follow the directions on the label of any pesticide.
Amendments by B. Sonsie Dip Hort Sc Burnley