Sunflower broomrape

Seedling

Where a germinated broomrape seed comes into contact with a sunflower root, a thickening forms.

Seed and fruit

• The seeds are very small: 1000 seeds weigh 0.008–0.010 g.
• The weight of 1000 seeds is 0.01 g; this is the lower limit of seed weight among weeds.

When to look

The first signs of the parasite are observed at the start of sunflower flowering, primarily on hybrids and varieties that are not resistant to it.

Agronomy

For a long time this parasitic weed did not do sunflower much harm, because immune varieties and hybrids were grown.

Biological control

If flowering stems are found, release of the Phytomyza fly is recommended, in line with the guidelines.

Life form

The best-known parasitic weed. It attacks sunflower, tobacco and tomatoes.

Emergence

• The seeds germinate when a host plant is present in the field, under the influence of its root exudates.
• The parasite's stem comes up to the soil surface after 35–65 days, depending on the point of attachment.
• A parasitic weed: the seeds start to germinate in response to sunflower root exudates.

Seed production

Seed production is high: on average 60–100 thousand seeds, and it can reach 1 million very small seeds.

Seed in the soil

The seeds stay viable for 5–10 years or longer.

Favourable conditions

In recent years the area under sunflower has grown several times over. This sped up natural selection in broomrape, and several of its races have appeared that can overcome the defences of the host plant.

Every fact rests on a quote from its source, and each quote was checked against the page it is printed on.

1. EPPO Global Database · European and Mediterranean Plant Protection Organization
2. Прогноз фітосанітарного стану агроценозів України та рекомендації щодо захисту рослин у 2025 році · Держпродспоживслужба, НААН, НАН · p. 114, 115
3. Зуза В. С., «Гербологія», монографія, 468 с. · Харківський державний біотехнологічний університет; Харків: Стиль-Издат, 2022 · p. 26, 50, 62
4. Photos: Eugene Popov, iNaturalist, CC BY 4.0 · Dmitriy Bochkov, iNaturalist, CC BY 4.0 · Oleksandr Shynder, iNaturalist, CC BY 4.0 · Aleksey Baushev, Wikimedia Commons, CC0 1.0