Stripe Rust Update: May

Tanner Sheahan
CPS Tangent

It has been about 6 weeks since our first observation of stripe rust in winter wheat this spring.  A couple weeks ago I posted some pictures of early infection sites in wheat fields and how untreated rust was penetrating into the leaf sheath.  Here are a couple more pictures I thought you might find interesting.

Fungicide buffer, Goetze wheat. 5 May 2010.

This field was treated by air about three weeks ago.  The applicator left a narrow buffer strip along the edge of the adjoining clover field that now shows up clearly with rather severe rust.

Fungicide buffer, Goetze wheat. 5 May 2010.

Here is a view of the same field looking the other direction.

Goetze stripe rust infection point. 5 May 2010.
This is another look at an initial infection site in an untreated field nearby.  The rust is not necessarily showing up where we would expect it to.  In this case it is the lower ground where the rust is progressing while the high ground behind it is pretty clean.

The disease is definitely progressing.  Spray skips and buffers are quite obvious in earlier infected/treated fields.  Initial infection points are now showing up in nearly every untreated field.  We have not had consistent temperatures necessary for the HTAP to kick in Goetze or Tubbs.  Fortunately we're getting pretty close, across the board, for the normal flag leaf fungicide application.  Talk with your CPS fieldman about fungicide options and timings.