American black nightshade (<i>Solanum americanum</i> Mill.) density and spacing line effects on tomato crop

Abstract

This work aimed to study the effects of the weed American black nightshade (Solanum americanum Mill.) density and distance (area of influence) on the development and productivity of tomato (Lycopersicon esculentum L. cv. Heinz 9992), by using the additive method. The experiment was carried out in semi-controlled conditions using pots with capacity equal to 70 L (area of 0.30 m²), filled with soil collected on the spot. The experimental design was conducted using completely randomized blocks in a factorial scheme of 3 x 3 + 2, with three replications. Three densities of the American black  nightshade (33, 60 and 100 thousand plants ha^-1) were evaluated along with three distances in relation to the tomato plants (0, 12 and 24 cm), added of two checks. Reduction in the production of tomato plants of around 25% and 9% were observed when they were at 12 and 24 cm in distance from the plants from the weed, respectively. Production was also reduced by 10 and 31%, when the tomato plants were in the presence of 60 plants and 100 thousand ha^-1 from the American black nightshade, respectively. In the end of the trial period, 120 days after the transplant, it was observed that the
density of 100,000 plants ha^-1 of S. americanum Mill., in the distance of 12 cm, is the most detrimental to the development and production of tomato plants.