LISTSERV 16.0 - MICH-ORGANIC Archives

Recently I received a summary of work by Reg Destree in beans. He was comparing brix and sap pH in soybeans and dry beans with aphid counts in Michigan, Illinois, and Wisconsin. With a brix of 9.5 and sap pH of 6.2 (6.4 is ideal) he found 0-10 aphids per plant. When the sap pH dropped to 5.3 and the brix was 5.7 average aphid counts exceeded 3500 per plant. I have heard and observed this phenomenon over the years but this is the first time I have seen numerical support.

In the orchard under my management, PC seemed to be less this past year. I have used garlic for several years as it is reported to repel insect feeding. This past season I added cedar oil to the program. My understanding is that cedar oil will interfere with insect sensors responsible locating food or mate. It is hard to say how much impact this had.

The other effort for PC control included the fungus Beauverria Bassiana marketed as Mycotrol O. This fungus attacks soil dwelling insects. Since it was applied last summer I should see less PC pressure this summer.

Jay McCaman