Effect of viral diseases on the production of lettuce grown under screened condition and transplanted at different distances from the source of inoculum - DOI: 10.4025/actasciagron.v29i2.234

Abstract

The effect of growing seedlings under screen house during different periods and transplanting at different distances from the source of inoculum were evaluated for viral disease effect on the production of lettuce Veronica cultivar. The experiments were conducted from June to September, 1999, adopting an entirely randomized experimental design with three replications. Seven periods of seedling protection and three planting distances from the virus inoculum’s source were tested. After each period of protection, the seedlings were maintained under anti-aphid screen and transferred to a greenhouse exposed to natural virus infection until they reached the stage of transplanting. No significant differences among the treatments regarding the time of protection of the seedlings, were observed. A gradient of production was also verified, that is, the further from the source of inoculum, the larger the productivity. The induced symptoms were attributed to LMV and LeMoV.