That's a tough question because there are no good published guidelines for reference. Right now, it's mostly a fly by the seat of your pants approach which is wide open for abuse. Many years ago, Syngenta used to recommend treating with Tilt when the number of lesions on the leaf opposite and below the ear leaf added up to the size of a quarter. With the stroby's being a preventative instead of a curative which is what Tilt is, I expand that to the second leaf below the ear. This is by far the best recommendation I have seen and it is what I will use until better guidelines come out.

Beans are a completely different story. In the absence of Soybean Rust, I see no circumstances that warrant a fungicide application. My opinion is based upon the research I have seen to date. This article from Iowa State sums it up well: http://www.ipm.iastate.edu/ipm/icm/2006/6-26/fungicides.html  In the article they say, "In 2005, fungicide studies were set up across the Midwest and northeastern United States. In all, 62 plots with different fungicide/timing combinations were completed. Significant yield results were encountered in 27 percent of these 62 replicated experiments. These experiments involved both large and small plot tests. In a separate fungicide study at the University of Kentucky during 2003-2005, plant pathologist Don Hershman looked specifically at "plant health" applications and if they led to economic benefits to producers. Over the three years of study, significant yield results were encountered in six of 24 experiments".

As you can see, it's not a very good track record for beans. More recent research has not been any better either.

[qoute]I believe the U of IL folks sent a letter 2 wks ago saying they did not understand either why yields increased w/fungicide application. They said that + response (but maybe not always enough) happened even in perfectly healthy stands.

Yes, that is correct but the key phrase was this: "Averaged over all 10 sites, fungicide increased yield by 6.2 bushels per acre. Neither yield level nor previous crop had a consistent effect on yield response to fungicide. At the reported cost of $20 to $25 per acre for the fungicide applied by air, the average response of 6.2 bushels would barely cover costs at $4 per bushel of corn, and it would not cover cost at today's corn price."

I understand your frustration Ron. But I'd like to remind you that IPM principles have been proven to work. IPM recommendations for Cutworms, Rootworm Beatles, Japanese Beatles, Armyworm, Spidermites, Bean Leaf Beatles, as well as a whole host of other pests have proven themselves over time. So your telling me that your going to throw IPM out the door because of one failure? 

There's no doubt that the initial aphid recommendations from the universities were flawed. I do think they have a better handle on the situation at the present, so I would encourage you not to discard IPM altogether. IPM has it's place. It discourages misuse and abuse of pesticides, which can have huge implications in the future.