Effects of inoculum density,leaf wetness duration and nitrate concentration on the occurrence of lettuce leaf spot |
| |
Authors: | Masahiro Nao |
| |
Institution: | (1) Ehime Agricultural Experiment Station, Kaminanba, Matsuyama 799-2405, Japan |
| |
Abstract: | In Ehime Prefecture, Japan, lettuce leaf spot (Septoria lactucae) caused huge losses in marketable lettuce yields. To explore potential measures to control disease outbreaks, the effects
of inoculum density, leaf wetness duration and nitrate concentration on the development of leaf spot on lettuce (Lactuca sativa) were evaluated. Conidia were collected from diseased plants in an infested field by single-spore isolation and were used
to inoculate potted lettuce plants with different conidial concentrations. Lesions developed on inoculated lettuce plants
at inoculum concentrations from 100 to 106 conidia/ml. The disease was more severe when the inoculum exceeded 102 conidia/ml, and severity increased with increasing concentrations. Assessment of the relationship between disease development
and the duration of postinoculation leaf wetness revealed that symptoms appeared when the inoculated plants remained wet for
12 h or longer. The number of lesions and total nitrogen content in the lettuce leaves both increased when nitrate was applied. |
| |
Keywords: | Lactuca sativa Lettuce leaf spot Septoria lactucae Passerini |
本文献已被 SpringerLink 等数据库收录! |
|