Silverleaf nightshade (Solanum elaeagnifolium, Cav.) is one of the important invasive plant species in Mediterranean Basin countries. Over the last 60 years, this plant has gone from a few accidental introductions to near monospecific populations in many areas of the Mediterranean Basin (in particular Greece and Morocco). Recent findings from Lebanon show that the invasion is ongoing. Solanum elaeagnifolium has a negative impact on crops, causing up to 75% yield loss, as well as an indirect impact by harbouring plant pests and diseases. Solanum elaeagnifolium is toxic to livestock and has a negative affect on the quality of life for humans. Losses of potential resource or revenue caused by its invasion include: decreased forage quality on grazing lands; decreased cropping land and amenity values of public space; increased water loss; increased water conveyancing costs; and increased forest restoration costs. Available control techniques need to be strengthened to reduce the impact of S. elaeagnifolium and prevent its spread. More attention needs to be devoted to biological control, which could provide regional management of this invasive alien plant. Sustainable management of S. elaeagnifolium will require coordination, education and support across the affected countries. Governments must have the means to detect, manage and control S. elaeagnifolium.

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Italian ryegrass interference in broccoli was measured in field experiments and the data fit a rectangular hyperbolic competition model. The model predicted 58% of broccoli yield loss related to Italian ryegrass density when pooled over three y. An economic threshold value of 4.9 Italian ryegrass plants m−1of crop row was determined to be the density required to cause a 3.6% yield loss, equal to postemergence weed control costs. Italian ryegrass densities of 600 to 1000 plants m1of broccoli row caused 100% yield loss.

In an effort to identify new herbicides for vegetables crops, broccoli (Brassica oleracea) cantaloupe (Cucumis melo), carrot (Daucus carota), head lettuce (Lactuca sativa), bulb onion (Allium cepa), spinach (Spinacia oleracea) and processing tomato (Lycopersicon esculentum) were evaluated in the field for tolerance to eight herbicides. The following herbicides and rates, expressed in a.i. lb/acre, were applied preemergence: carfentrazone, 0.05, 0.1, 0.15 and 0.2; flufenacet, 0.525; flumioxazin, 0.063, 0.125 and 0.25; halosulfuron, 0.032 and 0.047; isoxaben, 0.25 and 0.50; rimsulfuron, 0.016 and 0.031; SAN 582, 0.94 and 1.20 and sulfentrazone, 0.15 and 0.25 (1.000 lb/acre = 1.1208 kg·ha-1). Tolerance was evaluated by measuring crop stand, injury and biomass. Several leads for new vegetable herbicides were identified. Lettuce demonstrated tolerance to carfentrazone at 0.05 and 0.10 lb/acre. Cantaloupe and processing tomato were tolerant of halosulfuron at 0.032 and 0.047 lb/acre. Broccoli, cantaloupe and processing tomato were tolerant of SAN 582 at 0.94 lb/acre. Broccoli and carrot were tolerant of sulfentrazone at 0.15 lb/acre.

Four experiments (three in Macedonia, Greece and one in Holtville, CA) were conducted in 1988 and 1989 to evaluate foliar applications of picloram, glyphosate alone and with adjuvant, and triclopyr for the control of established silverleaf nightshade. Silverleaf nightshade control was determined by comparing stem population at the time of herbicide application to stem population 6 to 11 mo after application. Picloram, averaged over rate and location, controlled silverleaf nightshade consistently, restricting regrowth to less than 5%. Silverleaf nightshade control with glyphosate alone or with adjuvant varied with location, regrowth ranged from 0 to 69%. Regrowth of silverleaf nightshade treated with triclopyr approached that of the untreated control.