Recent advances in development of ultralow oxygen treatment for postharvest pest control on perishable commodities

Abstract

Purpose of review: This review summarises and discusses recent research progress in controlled atmosphere (CA) treatment with ultralow oxygen (ULO) for postharvest pest control on perishable commodities. Findings: In the last 10 years few studies have been conducted on ULO treatment for postharvest pest control. However, significant progress has been made and several ULO treatments were developed for postharvest pest control on different types of perishable products. Complete control of green peach aphid, sweetpotato whitefly, twopotted spider mite and western flower thrips was achieved with 18 h fumigation using >99% nitrogen without injury to begonia seedlings. Lettuce aphid, western flower thrips and black widow spiders were successfully controlled on head lettuce, broccoli and table grapes, respectively, without negative impact on product quality. Vine mealybug was successfully controlled without reducing the vitality of grape benchgrafts. The tolerance of lettuce to ULO treatment was increased through postharvest storage to improve the safety of ULO treatment. ULO treatment is promising for controlling selected pests on selected fresh commodities, especially on those that are evaluated for their vitality rather than appearance. Directions for future research: More research efforts should be directed towards identifying suitable pests and fresh commodities for ULO treatment. Emphasis should also be given to pest control on products such as rootstocks, bulbs and tubers, which are evaluated by vitality rather than appearance. Research should also be directed at enhancing the tolerance of commodities to CA treatment in order to make ULO and other CA treatments safer to product quality. Large scale studies and collaboration with industry are also vital for industrial adaptation of ULO treatment.