Partial efficacy of early and temporary roguing to manage woodiness disease in pilot crops of passion fruit

The potyvirus cowpea aphid-borne mosaic virus (CABMV) found in Brazil causes passion fruit woodiness, a difficult-to-control disease that limits the yield of the fruit crop. The present study assessed the effectiveness of systematic roguing of diseased plants as an alternative disease management strategy in three pilot passion fruit orchards. Passion fruit plants were grown on trellises and visually inspected for symptoms once or twice a week to identify and remove CABMV-infected plants. Systematic roguing of infected plants was initiated immediately after the detection of the first symptomatic plants after transplantation of seedlings to the fields and continued until approximately 20% of the plants were rogued. This effectively delayed infection in the young plants, as 80% remained healthy from 181 to 285 days after transplanting. At this stage of development, plants are more tolerant to virus infection. However, once roguing was interrupted, 100% of the remaining plants became infected within 64 to 126 days. In fields without roguing, the incidence of infected plants ranged from 65% to 100% at 90 days after transplanting. Although this study confirms the difficulty in managing the disease, the results also substantiate the systematic removal of diseased plants to effectively delay CABMV spread, thereby improving subsequent plant development and yield. To delay the spread of the virus, growers in passion fruit-producing regions are advised to inspect plants at least once a week after transplanting seedlings to the field and eradicating diseased plants during the first 5 months after transplantation.