Utvecklingen hos nattskatta (Solanum nigrum L.) och dess bekämpningsbehov i konservärtsodling
Black nightshade (Solanum nigrum L.) is a major problem in gardenpea cultivations
contracted by Findus AB, a Swedish food processing company. The main problem is that the
nightshade berries contain solanin and, thus, are not tolerated in the marketed product, which
is fresh frozen peas. In addition, berries have the same size and color as the peas and cannot
be separated at the factory. Black nightshades have the last ten years become a more common
weed in field grown vegetables in the southern parts of Sweden. This MSc thesis presents an
experiment conducted in 2005, aiming at developing a tool for predicting the need for control
of black nightshade in peas. The report includes a literature review concerning characteristics,
growth and plant development of black nightshade. Also, it includes a description of the pea
cultivation strategy of Findus AB. The experimental part consisted of registration of the
development of black nightshade in relation to pea plants. The registrations were done in pea
fields contracted by Findus AB. The study of development was conducted in fields with four
pea cultivars differing in earliness. No berries of black nightshade were produced before the
harvest of the two early pea cultivars. However, nightshade plants growing in fields with late
pea cultivars were able to produce berries before harvest, indicating a need for an effective
weed control. The data from these experiments was then compiled to form graphic
presentations for each of the species. These graphs show the relationship between the
development of black nightshade and peas, and can be used to predict the risk of nightshade
plants producing berries before harvest of peas. As a result, the data from these graphs can
assist farmers and weed assistants in determining whether or not black nightshade shall be
controlled.