Soybean Cyst Nematode Symptoms Beginning to Show!

I often refer to the negative impact the weather (stress) has on plants and how these conditions can favour disease pathogens. In the case of soybean cyst nematode (SCN), the more stressed the plant the more apparent visual disease symptoms become. Although soybean development has been occurring very rapidly in many parts of the province and the above ground symptoms may not be apparent, this does not mean you can afford to ignore SCN and what is happening in the ground!

Cysts are starting to be found on early to mid May planted soybeans and over the next few weeks, all growers in the province are encouraged to do their first SCN scout by carefully dig-up plants, gently remove the soil from the roots and examine them for the "pearl white to yellow" cysts.

Figure 1. Soybean Cyst Nematode

I purposely mention "all soybean producers" should be scouting for SCN since the nematode continues to move to new areas of the province and most recently has been identified in mid-eastern (Trenton-Kingston) and in the far eastern portions of the Ontario.

It is important for growers in the traditional SCN areas of southwestern Ontario to also examine plants for SCN even if they are growing (and they should be!) SCN resistant varieties. The majority of SCN varieties have the PI 88788 source of resistance which is still very effective under Ontario conditions and a recent survey coordinated by Tom Welacky (Agriculture and Agri-Food Canada at Harrow) and OMAFRA illustrates this.

In the next few weeks Tom and I will be putting more information into the CropPest Ontario.