Diamond for Southern Corn Rootworm Control Peanut Notes No. 148 2020

(Updated: July 20, 2020, 4:35 a.m.)

Question (paraphrase):

Does Diamond sprayed twice at 6 oz/acre with fungicides serve as a good alternative to Lorsban (chlorpyrifos)?

Jordan Answer:

I am going to forward your question to Rick.  Have those recommending this ever looked at an untreated area versus a treated area in the same field?

Answer:

Not sure.  I never have.

Jordan Answer:

I don’t think there is any evidence that Diamond controls rootworms. Rick has looked at a lot of products over the years and nothing controls rootworms other than Lorsban.

Brandenburg Answer:

Diamond is a chitin inhibitor that to my knowledge doesn't even have any insects even closely related to a rootworm on the label.  I am aware of no data to support this claim.

Jordan Follow Up:

Keep in mind that we might not see injury from a pest but that does not mean a product controlled the pest even though it was used.  The cause and effect relationship is important to establish.  Rootworms are a good example.  We have many fields where this pest never develops regardless of whether or not we treat.