Manitoba Insect and Disease Update: May 27, 2014

 

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Summary: Some localized wireworm damage to wheat has been reported in the Eastern and Central regions. Diamondback moth trap counts remain low.

 

Knowing what is and is not a wireworm 

While looking in the soil, there are various invertebrates that could possibly be confused with wireworms. I have had a few "wireworm" enquiries where what was described sounded more like enchytraeid worms.

Figure 1 shows a wireworm. Note the 3 pairs of small legs at the front of the body.

Figure 2 is the larvae of a stiletto fly (sometimes called therevids). They have no legs and will thrash around a lot when disturbed. They are predators.

Figure 3 is a centipede. They are fast moving predators, and will have 15 or more pairs of legs.

Figure 4 is an enchytraeid worm. They feed on dead plant material and fungi and will not damage living plants.

 

                    
 Figure 1. Wireworms                                                    Figure 2. Therevid

 

     
  Figure 3. Centipede                                     Figure 4. Enchytraeid worm. Photo from Terry Buss/Earl Bargen

Monitoring Wheat Fields for Wheat Steak Mosaic. Four winter wheat fields were recently checked for wheat streak mosaic. In one of the fields the stubble from the canola was cut really short and there was patchy winter kill. In fields with tall stubble the winter wheat survival was very good. Wheat streak mosaic was not found in any of the fields. Growers need to check their fields to confirm they don’t have the disease. 

 

 

Diamondback Moth: From May 24-26 there were a number of winds crossing the prairies that originated over southwest USA and Mexico. This is the first time this spring that this has occurred. However, counts are still low in the diamondback moth traps. So there is no evidence yet of diamondback moth being blown in and deposited in Manitoba. Highest trap counts so far are:

Location	Region	Count
Durban	Valleys North	12
St. Adolphe	Red River	12
River Hills	Eastman	7
Elma	Eastman	6
Stread	Eastman	6
Ninga	Ninga	4