Field Management Program for High-Risk Processing Tomato Fields

Purpose

This page is intended for growers operating under Exhibit G1 for a high-risk processing tomato field or fields. It combines the main elements expected in a field management program with current UC recommendations on planting, chemigation, scouting, rogueing, sanitation, and post-harvest risk reduction. It is written to help operations turn the compliance agreement exhibit language into a practical field plan.

Required Under the Current Compliance Agreement

 For high-risk processing tomato fields, the compliance agreement requires a field management program that covers pre-transplant, growing season, and post-harvest management. That program must include broomrape education for all field personnel and contractors authorized to enter the field, a designated area for equipment entering and exiting the field and cleaning of equipment so it is reasonably free of soil and plant debris before it leaves the field. The establishment must also use the Board-recommended growing degree day model to develop a scouting and rogueing plan, dispose of suspect broomrape plants in accordance with the field management plan and Board guidance, and require footwear cleaning before field exit. In addition, the contracted processor must be notified at least 48 hours before planting or harvesting a high-risk field, and the exact location of the first suspect broomrape plants found during the season must be reported immediately to the processor, and to the Program as well if the detection is outside the Designated Zone.

UC Recommended Field Management Framework

A. Before Transplanting

Before planting, identify and mark a single equipment cleaning area inside the field perimeter, not on a road, turn row, or driveway.
- Use that location throughout the season for cleaning equipment and footwear before they leave the field.
- That location should also be monitored in later seasons because debris removed during repeated cleaning can concentrate risk in that area.
Current UC work suggests that later planting can reduce broomrape parasitism in infested fields, with better outcomes observed in fields planted after early to mid-May.
- Select the latest practical planting date for the field while still fitting the region, production system, and processor delivery schedule.
Within the Designated Zone, growers may have both high-risk and lower-risk fields.
- Because broomrape spreads by seed and seed movement with soil on equipment is a likely mechanism of spread, sequence field operations from lower-risk fields to higher-risk fields where practical.

B. At Transplanting and Early Season

Train field staff, irrigation personnel, scouts, equipment operators, and contractors to recognize broomrape and report suspect plants immediately.
- The bilingual awareness flyer is a useful basic training tool because it reinforces that even a single suspect plant matters and should be reported right away.
In the early season, enter the target or actual transplant date and field location into the broomrape growing degree day calculator so projected windows for chemigation, scouting, and rogueing can be generated for planning purposes.
- Because projections more than about two weeks out rely on historical averages, they should be checked again closer to the expected activity date.

C. Growing Season

For high-risk fields, UC currently recommends using the Matrix SG chemigation protocol because it is currently the only approved herbicide program for broomrape management in California processing tomatoes.
The current label-based program is three applications of 1.33 oz per acre at about 30, 50, and 70 days after transplanting, injected near the midpoint of the irrigation set and followed by enough water to flush the system.
In some UC experiments, earlier applications, around 20, 30, and 40 days after transplanting, improved control of the earliest germinating cohort. Current recommendations are to use the Growing Degree Day (GDD) model to better account for broomrape phenology with earlier and later planting dates.
Although there are other chemical and genetic management approaches in the research and registration pipeline, these will not be included here until they receive full registration and are available to California growers.

D. Scouting and Rogueing

Use the growing degree day tool to set target windows for scouting and rogueing.
Print or save the worksheet so target dates and completed activities can be documented. Broomrape emergence typically begins around 400 GDD after transplanting.
Current best practice for high-risk fields is to scout and rogue twice, first about 6 to 8 weeks after transplanting and again about three weeks later, with a third rogueing pass if plants remain present.
Removed plants should be bagged immediately and handled according to the disposal guidance.
Do not wait for a large infestation before beginning rogueing. Early removal is intended to reduce further seed production and seedbank buildup.

E. Mapping the Infestation

As suspect broomrape plants are found and removed, mark and map their locations in a consistent way so those areas of the field can be revisited for follow-up scouting, rogueing, and future management.
The method can be simple: field flags, GPS pins, hand-drawn maps, or other records that note row, location, and level of infestation.
Over time, these records can help show whether infestations are staying contained, expanding outward, or appearing in new areas such as entry points, field exits, equipment cleaning areas, or other locations where soil and plant debris accumulate.

F. Harvest and Post-Harvest

Maintain the designated cleaning area and keep sanitation expectations in place through harvest and after harvest.
The risk of broomrape spread does not end with tomato season.
Seed can persist in soil for many years, and equipment movement during post-harvest work, tillage, bed preparation, and rotational crop operations can still spread seed.
Continue minimizing unnecessary movement of soil and debris from the field during harvest and outside the tomato season. See the out-of-season field management page for additional guidance.