Management tools for dealing with midge | Further information links | How the survey was done | Who helped .
This forecast is not intended to take the place of individual field monitoring. The forecast for Alberta shows areas of risk for midge damage in 2016. It is important to note that over such a wide range, populations in individual fields can be and often are highly variable. Producers should plan to monitor their fields when the midge adults are flying and their wheat is in the susceptible stage. In all areas of the province growers are urged to monitor their wheat fields from wheat head emergence to anthesis for the presence of midge adults. Regular field scouting on multiple nights in succession is important in understanding the population in a particular field.
|The wheat midge forecast for 2016 shows an overall lower level of wheat midge across Alberta. There has been a slight bounce back from the collapse of the extreme populations in the eastern Peace Region. Although wheat midge has not followed our forecasts very well in the Peace region it is important to note that there are likely sufficient populations of midge in the eastern Peace to fuel a resurgence if conditions are in the insects favor. (specifically delayed crops and higher than normal rainfall). Central Alberta has some areas of east of Edmonton with high numbers of wheat midge. The population has remains low in much of southern Alberta with the exception of some irrigated fields. Producers should pay attention to midge downgrading in their wheat samples and use this as a further indication of midge risk in their fields. Over the past several years the field to field variation has been very considerable throughout the province, especially in those areas with higher counts. Individual fields throughout Alberta may still have economic levels of midge. Each producer also needs to assess their risk based on indicators specific to their farm.|
||Although a number of factors influence the overwintering survival of the midge, the survey and map provide a general picture of existing densities and the potential for infestation in 2016. Weather conditions, specifically temperature and moisture will ultimately determine the extent and timing of midge emergence during the growing season. Temperature and wind also play critical roles in egg laying activities of the adult female wheat midge. The level of damage from wheat midge is determined by the synchrony of wheat midge emergence and wheat and the number of wheat midge present. Look for the results of our wheat midge pheromone trapping in June and July to help track the emergence of adult midge.|
|Parasitism of midge larvae by a small wasp species (Macroglens penetrans) has been important in keeping wheat midge populations below the economic threshold in many areas. These beneficial wasps tend to thrive in warm, dry conditions. Parasite populations increase and decrease with changes in the midge population and are very important in moderating population levels in Alberta.
It is important to understand that once midge has established in an area it unlikely to ever completely disappear. Low lying and moist areas in a field provide a refuge, enabling the population to survive even when conditions are not favorable in the rest of the field. These low population levels, however, also help sustain a population of natural enemies.
Management tools for dealing with midge
How the survey was done
The 2015 fall survey included wheat growing areas throughout Alberta. In total 337 samples were taken from 61 counties. The survey involves taking soil samples from wheat fields after harvest using a standard soil probe. Larval cocoons are washed out of the soil using a specialized series of screens. Larvae are counted, and then dissected to determine if they are parasitized. The midge density displayed on the forecast map is based on viable (live, non-parasitized) midge larvae
Wheat midge cocoon compared to canola seed
Wheat midge larva
Wheat midge larva compared to canola seed
The wheat midge survey was conducted by Alberta Agriculture and Forestry with assistance from:
Thank you to the many producers for permission to survey their fields. If you are interested in taking part in the 2016 wheat midge survey contact us.
Updates of current conditions and wheat midge emergence will be available through the Ag-Info Centre (310 FARM) during the 2016 growing season.
Follow this link for a printable version of the map.
Historical wheat midge forecast maps from 2006 - 2015