December 2010

Source: Ohio State University Extension, C.O.R.N. Newsletter 2010-40
Ron Hammond, Andy Michel

Many of you have become aware of the rating system that Pioneer is using to differentiate their soybean varieties in their susceptibility to the soybean aphid.

Although perhaps a useful system, we wanted to reiterate what they themselves state about this system.

This rating scale “should NOT be used for choosing which varieties to select and plant”.

Their intention is for this rating system to be used as a management tool during the summer if, and only if, soybean aphids become a problem (of which 2011 is a likely to be an “aphid year”).

As stated in their information, “ratings should be used by growers to help in determining field scouting priorities and insecticide application decisions should an infestation of soybean aphids occur”.

The intent is to use the ratings to select varieties that should be scouted first and then with more frequency, those with a “below average” rating.

A variety with an “exceptional” rating should also be scouted, but perhaps following those with lower ratings.

Pioneer recommends using these aphid antibiosis ratings along with diligent scouting and timely insecticide application.

Thus, none of their varieties, nor other companies, should be considered “resistant” unless it is so stated, which will be because they will have the new Rag1 gene that some companies are incorporating into their varieties.

Website: http://www.osu.edu

Published: December 7, 2010