Soybean Stem Fly

Key Points

• Stem fly can be present but undetectable. Growers need to carefully monitor crops for early signs
• Growers should look for pinprick holes in leaves and stems, and tunnels in stems containing larvae and pupae; tunnels can only be found by splitting open the stems
• Stem-fly damage leads to smaller seeds and non-uniform grain, and it may prevent grain fill altogether; this reduces yield and increases production costs because seed has to be graded
• Stem fly first appeared in 2013 in northern NSW after sustained hot and humid conditions. If similar conditions occur this year, crops could be at substantial risk of damage
• The GRDC encourages growers to take an integrated pest management approach to controlling stem fly

This fact sheet tells you how to identify stem fly, what treatment options are available and where to find more information.