First Report of <i>Monarda didyma</i> Infection with <i>Impatiens necrotic spot virus</i> in Washington State

Fig. 4. RT-PCR analysis of total RNA extracted from leaves of four field-grown M. didyma plants: two asymptomatic and apparently healthy plants (H) and two plants with symptoms consistent with INSV infection (I). A DNA fragment of approximately 1.3 kilobase pairs specific to the NSs gene of INSV was amplified only from symptomatic plants in Figs. 1 and 2. DNA molecular weight markers (Mr) are shown on either side.

Image from Plant Health Progress article:
First Report of Monarda didyma Infection with Impatiens necrotic spot virus in Washington State