The 41st Annual Citrus Post-harvest Pest Control Conference was hosted by the Citrus Research Board and UCANR. (Photo: Valley Ag Voice)

Limited post-harvest technologies result in citrus fruit decay. 

Natalie Willis, Reporter, Valley Ag Voice

After harvest, crops undergo a detailed post-harvest process to ensure the food is safe and FDA-approved. The 41st Citrus Post-harvest Pest Control Conference on Sept. 6 brought the small post-harvest community together to discuss new technologies, food safety protocols, and numerous regulations for citrus fruit. 

Post-harvest losses due to disease account for roughly 30% to 50% of total production, a study from the Journal of Horticulturae explained. The EPA also estimates approximately 31 million metric tons of food is wasted each year after harvest, accounting for 14% of solid waste dumped into landfills.  

According to Tarcisio S. Ruiz, director of Post-harvest Technologies at Fruit Growers Supply, most of the losses for citrus are due to decay, but post-harvest fungicides are limited. 

“For citrus, particularly, we only have six fungicides, maybe seven, for decay control, but we have two main pathogens for citrus in post-harvest, and one of them is penicillium — green mold and blue mold — and the other one is sour rot,” Ruiz said. “Well, for sour rot, we only have one fungicide available, for penicillium, we have the other ones, and we need more tools in order to protect the food.” 

In comparison, there are more than 1,000 pre-harvest pesticides used to mitigate weeds, insects, and other pests, according to the U.S. Geological Survey. 

At the conference, Pauline Voorbraak from Janssen Preservation and Material Protection explained that the post-harvest fungicide market is estimated at $245 million, whereas pre-harvest fungicide is $18 billion. She explained that the need for more fungicide technologies is evident, but the cost of introducing a new chemical to the market has limited the scope of reality for post-harvest efforts. 


The Citrus Post-harvest Pest Control Conference started in 1978 with the intention of addressing critical areas for the post-harvest citrus community. The annual conference is moderated and organized by Mary Lu Arpaia, horticulturalist and statewide extension specialist for subtropical fruit at UC Riverside. 

The 41st conference was held in Visalia and sponsored by the Citrus Research Board as well as the University of California Agriculture and Natural Resources. Industry professionals presented various technical aspects of the citrus industry, including post-harvest disease control, managing chemical residues, and food safety. 

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