Wheat Blossom Midge

Wheat Blossom Midge

Key Points

^•	Wheat blossom midge is a sporadic pest but can be devastating
^•	Damage caused will affect crop yield, quality and acceptance for milling
^•	No product will kill larvae once they have entered the glume
^•	Water volume should be maintained to ensure good coverage and contact with the pest
^•	Only chlorpyrifos is approved in the UK for the control of Wheat Blossom midge

Related Links

Wheat Blossom Midge: Biology

Wheat Blossom Midge Risk Assessment Chart

Cereals Pestwatch

Dursban WG Product Page

Introduction

Wheat Blossom Midge Larvae

Wheat Blossom midge is a sporadic and occasional pest that occurs in some crops in the UK every year. Two species of wheat blossom midge are pests of cereal crops. These are orange wheat blossom midge, Sitodiplosis mosellana, and yellow wheat blossom midge, Contarinia tritici.

The larvae of both species feed within the floret and can be distinguished by their colour and key differences in their biology and life cycle. Outbreaks tend to be sporadic with both species able to attack wheat, barley, oats and rye. Significant damage to UK cereal crops has only been reported in wheat and rye.

Some winter wheat varieties are confirmed as having genetic resistance to orange wheat blossom midge, but not to yellow wheat blossom midge.

For more information on the biology of wheat blossom midge, click here.

Control Options

If adult midges have emerged and are present in the crop the Wheat Blossom Midge Risk Assessment Chart will help identify if and when an application of Dursban WG is justified. ALL conditions must apply if an application is to be made:

1. All environmentally sensitive areas identified

2. Crop growth stage between ear emergence and flowering, GS53-59

3. Adult midges found in crop

4. Thresholds met or exceeded:
a. Seed and milling crops – 1 or more adults per 6 ears
b. Feed crops – 1 or more adults per 3 ears

5. Leave an unsprayed headland of at least 12 metres.

Learn more about Dursban WG.

Safe Spray Guidelines:

If treatment of Wheat Blossom midge is necessary and justified, then spraying needs to be undertaken in a way that will minimise effects on wildlife.

^•	Walk the crop daily on warm still evenings to check for the presence of adults. Pay close attention to crops at ear emergence (GS53-59) and assess each field individually. Consider the use of pheromone traps or yellow sticky cards at the highest risk sites. Spray only where thresholds are met or exceeded — one or more adult midges per 6 ears in seed and milling crops; one or more adult midges per 3 ears in feed crops.
^•	Assess the area to be sprayed carefully. Take note of surrounding wildlife features like ponds, woodlands and hedgerows and consider the whole farm in the context of the affected area. Only spray affected areas.
^•	Ensure spray operating staff are fully trained and know which areas are to be sprayed.
^•	Avoid spraying near field margins leaving a 12 metre headland unsprayed. At high risk periods hedges will be rich in the insect species needed to provide food for fledglings. Damage done to young bird populations now may affect future bird numbers.
^•	Use techniques to avoid spray drift. Check sprayers are calibrated correctly and produce the appropriate spray quality. Choose drift-reducing nozzles where possible.
^•	Avoid spraying in windy conditions or if the day is warm and still. Spray early in the morning or preferably late in the evening when most flying insects are not within the crop. Always warn local beekeepers of your intention to spray.

Always check Cereals Pestwatch pages for the most recent bulletins.