An internal control for the diagnosis of crown gall by PCR

The addition of an internal control (IC) at the appropriate concentration enables recognize of false negatives in the detection of Agrobacterium tumefaciens and improves the reliability of PCR for crown call diagnosis. Co-amplification of the IC and target sequence from A. tumefaciens ensures the attainment of at least one amplification product in every PCR reaction if the DNA extracted is of high enough quality to be amplified