Skip to content

Cool spring condition to affect insect numbers

Cool spring conditions have decreased the risk of bertha armyworms and grasshoppers in southeast Saskatchewan.



Cool spring conditions have decreased the risk of bertha armyworms and grasshoppers in southeast Saskatchewan.

There were only a few reports of bertha armyworm moths in traps because cool spring conditions slowed emergence of the moths from over-wintering pupae. The risk to cruciferous crops, primarily canola and mustard, from bertha armyworm is likely to be low across the region. The appearance of destructive larvae of the bertha armyworm is late July and August.

The cool and wet conditions during 2010 were also not favourable for grasshoppers, and most areas of the region have a reduction of the pest. The flowering and pod stages of lentil crops are more vulnerable to grasshoppers feeding with potential economic damage.

Monitoring for young grasshoppers in susceptible crops usually occurs in the spring and early summer, but since southeast farmers were still dealing with excess moisture and were unable to seed many acres, this will decrease the grasshopper count even further.

The main concern for producers will be the wheat midge, as risk maps show an increased threat from the insect pest for the upcoming growing season.

The potential for economically damaging infestations is to wheat crops. While many southeast producers couldn't seed spring wheat, they should monitor their fields when planning to plant winter wheat. An insecticide application is recommended when the crop is heading and adult midge density is one midge per four to five heads.

Spring precipitation is a key factor affecting the emergence of wheat midge, and excess moisture will increase the amount of wheat midge emergence. Appearance of the adult midge may be erratic and could occur over an extended period.