Delayed Planting Dates

Delayed Planting Date

To reduce broomrape parasitism, UC research suggests a benefit to planting infested fields as late as feasible for the region (e.g., late April to early May for processing tomatoes) and delivery schedules. This is likely due to a shortened period of soil conditions most conducive to broomrape germination and attachment as the soil temperatures warm in the late spring and early summer.

  1. High Risk Fields:  Strongly encourage known-infested or high risk fields to be planted as late as feasible.
  1. Designated Zone: Encourage “zonation” practices for all fields in the designated zone for scheduling planting and other field operations to start with lower-risk fields and end with higher-risk fields to reduce the risk of moving soil/seed from infested to non-infested fields. 
A field with a row of tomatoes labeled 1, 2, and 3
Figure 1 Tomatoes from a 2024 planting date study near Woodland, CA, with flags marking individual broomrape clusters in one replicate of the early (1), mid (2), and late (3) planting dates approximately 110 days after transplant. Individual plots are full rows and different color flags represent different times of broomrape emergence and discovery.