Yellow cereal fly biology and management

Yellow cereal fly larvae feed in the shoots of cereal crops, causing classic ‘deadheart’ symptoms, which may be confused with wheat bulb fly or frit fly damage. However, the risk of economic impacts from yellow cereal fly is low as each larva only attacks a single tiller.

• Early sown crops in sheltered fields close to woodland are at increased risk
• Increased risk to crops with low plant populations

Scientific name: Opomyza florum

Adult flies are small (5.0–5.5 mm long) with an orange–brown body and black wing markings.

Larvae are yellow with pointed ends. They are thinner than wheat bulb fly larvae and like frit fly larvae (though occurring later in the winter).

Nov–Feb: Eggs overwinter.

Feb–Mar: Eggs hatch.

Feb–May: Larvae enter and feed on wheat shoots, resulting in classic ‘deadheart’ damage, whereby the central shoot becomes yellow and dies. The point of entry shows as a clean, brown line encircling or spiralling around the shoot (in contrast to the ragged hole left by wheat bulb fly).

May: Larvae pupate in the shoot or soil.

Jun–Jul: Adult flies hatch.

Jun–Aug: Adults spend the summer in woodland.

Sep–Oct: Flies move to early sown wheat crops.

Oct: Eggs are laid on the soil at the base of host plants.

Symptoms are like frit fly damage, particularly in winter wheat, but are not noticeable until spring. Yellow cereal fly and wheat bulb fly larvae both feed in crops at the same time of year.

Non-chemical control

Ground beetles feed on soilborne eggs and pupae. Ladybirds and soldier beetles feed on pupae.

It should be possible to avoid economic damage by planting at least 200 plants/m² in vulnerable situations.

Monitoring

Plant dissection can determine the level of pest infestation. However, as the economic effect of yellow cereal fly is generally low, it is rarely worth monitoring.

Thresholds

None established.

Insecticide resistance

None known.