Minimal Necessary Weed Control Does Not Increase Weed-Mediated Biological Pest Control in Romaine Lettuce (Lactuca sativa L., var. Romana)

Lettuce is one of the most consumed leafy greens. Depending on variety, it ready for harvesting 40–80 days after sowing, and therefore several growth cycles can be concluded within a growing season. Due to its high market standards, lettuce may require intensive management. This study implemented critical period weed interference (CPWI) trial understand at which moment cropping cycle weeds tolerated without impacting crop yield decrease time needed weeding assess potential support give biological pest control in lettuce. Treatments represented two gradients intensity: (1) increasingly weed-free, (2) weedy. Dose–response curves were produced find CPWI based relative yield. RLQ analysis was used explore relationships between regime functional traits control. Yield above 5% acceptable loss threshold all plots kept weed-free 20 or more, indicating necessary from transplanting. However, beneficial insects not guaranteed end period. We suggest that possible limit intense management beginning season, reducing cost plastic mulches increasing on-farm biodiversity, but field margins could better suited deliver conservation short-term crops where this service primary interest.