A characteristic feature of this species is its long, linear cotyledons, with the first true leaf distinctly triangular.

It has a yellowish-brown, spindle-shaped, deep, and branched root. The stem is 20 to 100 cm tall, angular, branched at the base, twining, rough, with short hairs. Cotyledons are linear, 10–20 mm long, hairless, green, reddish underneath, rounded or blunt at the tip. True leaves are cordate-lanceolate, petiolate, sharply pointed at the apex. The inflorescence is spike-like, consisting of inconspicuous greenish-white flowers. The fruit is a three-angled achene, black, pointed at one end. Seeds are oblong, and one plant can produce 100 to 300 seeds, which can remain viable for up to 20 years.

Occurrence and Harmfulness

Black bindweed occurs in cereal crops, root crops, vegetables, and ruderal sites. It colonizes almost all soil types, is not sensitive to drought or nutrient deficiency, but develops poorly on acidic soils.

The pest’s harmfulness lies in its tendency to entwine cultivated plants, promoting lodging, hindering mechanical harvesting, and increasing tuber damage. Seeds can germinate even from a depth of 20 cm and may be spread with manure and slurry.

Control Methods

Mechanical Method

The long period between planting and potato emergence is a critical time (ideal conditions for weed development), which can be used for mechanical treatments. These are carried out using available farm machinery, e.g., hilling machines, light harrows, hoes, etc. Their main task is to create favorable conditions for rapid weed seedling emergence, followed by destruction with subsequent cultivation passes. The highest effectiveness (over 90%) is achieved when weeds are in the seedling stage, but effectiveness drops to about 40% as weeds grow. This system heavily depends on weather and soil conditions. In very wet springs, mechanical methods are difficult to apply. On heavily infested fields, mechanical methods may backfire, as damaged perennials’ rhizomes (like couch grass) may be stimulated to stronger growth and branching. Mechanical control is also labor- and cost-intensive due to multiple passes. This method is mostly used in small farms growing potatoes for self-sufficiency and in organic systems. Before potato emergence, 3–6 treatments should be applied at 6–8 day intervals. After emergence, the number of passes should not exceed 2–3, as delays increase crop damage and the risk of pathogen transfer via sap, and may overly dry the soil (especially light soils).

Mechanical-Chemical Method

The most favorable and widely used weed control system. It saves on mechanical treatments, which are used less than in purely mechanical systems. Usually, two or three hilling passes are done after planting, and shortly before emergence a herbicide treatment is applied, after which no further cultivation is done. During this stage, identifying weed species may be difficult; therefore, a treatment diary, maintained by each professional pesticide user, can help determine which weed species may pose a threat in a field.

Chemical Method

The most effective control method is using herbicides, which are most effective on this species at the seedling stage; the more vigorous the growth, the lower the effectiveness. In potatoes, herbicides are applied in two main timings: pre-emergence and post-emergence. Before applying, the herbicide label-instructions should be carefully read, including application timings and dosages. Some active ingredients have medium effectiveness, and results may be unsatisfactory if the weed is dense or in an advanced growth stage.

On heavily infested fields, a non-selective herbicide containing glyphosate can be applied, known as the simplified system. Success depends on the presence of weeds on the field, as glyphosate is absorbed only through leaves and cannot contact emerging potatoes, which would be destroyed. Even potato sprouts just below the soil surface may be damaged (photos A, B). Timing must match weather conditions, mainly temperature and rainfall, which are often decisive for effectiveness. Pre-emergence herbicides applied too late, when potato sprouts are just under the soil, can damage the crop after heavy rain. Some pre-emergence herbicides can still be applied in early potato growth stages (~5 cm height), e.g., prosulfocarb + metribuzin.

Active substances controlling black bindweed pre-emergence: chlormazon, linuron, linuron + chlormazon, metribuzin, metribuzin + chlormazon, pendimethalin, pendimethalin + chlormazon, prosulfocarb + metribuzin.

Post-emergence herbicides should be applied no later than the row closure stage to ensure weed coverage and avoid retention of spray solution on potato leaves. Due to pre-harvest interval limitations, post-emergence herbicides cannot be used for the earliest harvest!

Active substances controlling black bindweed post-emergence: bentazon and metribuzin. Metribuzin applied post-emergence may cause phytotoxic reactions in some potato varieties.