First Report of Broomrape (Orobanche crenata) Infecting Lettuce in Southern Spain

Area of Science:

• Plant Pathology
• Agricultural Science
• Botany

Background:

• Broomrapes (Orobanche spp.) are root parasites causing significant crop losses globally.
• Orobanche crenata is a major broomrape species, primarily affecting legume crops.
• Parasitic plants pose a substantial threat to global food security and agricultural productivity.

Purpose of the Study:

• To document the first confirmed incidence of Orobanche crenata parasitizing lettuce (Lactuca sativa) in Spain.
• To identify the parasitic species using morphological and molecular methods.
• To assess the impact of Orobanche crenata on commercial lettuce crops.

Main Methods:

• Field observations of parasitic plant infestations on lettuce crops in southern Spain.
• Morphological characterization of broomrape specimens.
• DNA sequencing of the ITS1-5.8S-ITS2 region for species identification.
• Nucleotide BLAST searches for sequence comparison.

Main Results:

• Severe Orobanche attacks were observed on fall-sown lettuce crops, with 10-20% incidence.
• Morphological and molecular analyses confirmed the parasite as Orobanche crenata.
• Orobanche crenata was also found infecting nearby faba bean crops.
• Sequenced DNA confirmed 100% similarity to known Orobanche crenata sequences.

Conclusions:

• This is the first report of Orobanche crenata infecting lettuce in Spain and globally.
• Orobanche crenata poses a significant new threat to fall-sown lettuce production in southern Spain.
• The widespread presence of Orobanche crenata on legumes suggests a potential for increased crop switching and damage to other hosts.