Cal Poly Partnership Introduces Technology to Reduce Pesticide Use

SAN LUIS OBISPO — An advanced method of treating citrus before it leaves San Luis Obispo County will eliminate more than 700,000 gallons of pesticide per year currently being used to control agricultural pests. 

The wash line is the latest Learn by Doing enhancement made possible by the continued partnership of Cal Poly’s College of Agriculture, Food and Environmental Sciences and Bee Sweet Citrus, a prominent citrus packing and shipping company based in the Central Valley.  

A state-of-art wash line for processing citrus and a 14,900-square-foot steel canopy to protect it were installed by Bee Sweet Citrus at the Bartleson Ranch in Nipomo. The 450-acre avocado and lemon ranch, donated to Cal Poly in 2015 by Stu and Jan Bartleson, is used as a site of extended hands-on learning and research opportunities for students studying horticulture, fruit science, soil science and more.   

“Five years ago, Cal Poly was gifted the land to extend our hands-on curriculum, and now we are being given the technology,” said Andrew Thulin, dean of the College of Agriculture, Food and Environmental Sciences. “The generosity of our partners provides essential educational opportunities for our students in sustainable practices that will benefit generations to come.”  

The wash line will provide a significant environmental benefit to the agriculture industry in San Luis Obispo County and beyond. This is the first wash line of its kind in the Central Coast region (including San Luis Obispo County and five other counties) — providing a place to wash and process citrus for transportation south. It is beneficial in two significant ways: providing increased control of the Asian citrus psyllid pest (which is known to damage citrus crops), and dramatically reduce the amount of pesticides used on those crops.

State regulations require that all citrus must be washed or sprayed with pesticides to prevent the Asian citrus psyllid pest from spreading. The new wash line facility ensures the safe transportation of citrus between regional areas. The wash line installation was managed by Cal Poly alumni Thomas Marderosian, one of three sons of Bee Sweet Citrus founder Jim Marderosian to graduate from Cal Poly, and Matt Watkins, who is involved in pest management. Cal Poly alumnus Francisco Zepeda will oversee the program.  

The media is invited to attend an unveiling ceremony at 1:30 p.m. Friday, June 12, at the Bartleson Ranch. Contact AnnMarie Cornejo at for additional details about the event. 

About Cal Poly’s College of Agriculture, Food and Environmental Sciences
Cal Poly is a nationally ranked, comprehensive polytechnic university. The university’s College of Agriculture, Food and Environmental Sciences ( is comprised of expert faculty members who take pride in their ability to transform academically motivated students into innovative professionals ready to solve the complex challenges associated with feeding the world in sustainable ways. Students have access to state-of-the-art laboratories, including ranch land, orchards, vineyards and forests, all of which provide the basis for Cal Poly’s Learn by Doing methodology. It is the fifth-largest college of agriculture in the country, with 4,000 undergraduate students.

About Bee Sweet Citrus 
A grower, packer and shipper of California citrus, Bee Sweet Citrus is a leader in today’s agriculture industry. Founded in 1987, Bee Sweet Citrus is a family owned and operated company and provides more than 15 different varieties of citrus to its consumers. Located in the heart of California’s Central Valley, Bee Sweet is focused on innovation, sustainability and customer satisfaction. Visit

Contact: AnnMarie Cornejo 

June 9, 2020

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