Location: Crop Improvement and Protection Research2012 Annual Report
1a. Objectives (from AD-416):
1. Develop controlled atmosphere treatments for postharvest pest control on perishable commodities. A) Develop semi-commercial scale storage and ultralow oxygen combination treatment for control of western flower thrips on head lettuce. B) Develop semi-commercial scale storage and ultralow oxygen combination treatment for control of western flower thrips on broccoli. C) Develop controlled atmosphere treatment for control of mealybugs and black widow spiders on table grapes. D) Develop ultralow oxygen treatment for control of vine mealybug on grape rootstocks. 2. Develop pure phosphine funigant treatments for highly perishable commodities. A) Develop fumigation treatment with pure phosphine for control of western flower thrips on lettuce, broccoli, asparagus, and strawberries. B) Develop fumigation treatment with pure phosphine for control of lettuce aphid and leafminer on lettuce. C) Develop fumigation treatments with pure phosphine for control of mealybugs and spiders on table grapes.
1b. Approach (from AD-416):
The minimum duration of pre-treatment cold storage needs to be determined in order to reduce the overall duration for completing ULO treatment and make it possible for pre-export ULO treatments. Effectiveness of ULO treatments for thrips control and their effect on postharvest quality of lettuce needs to be determined in large-scale tests. Oxygen consumption rates and oxygen demands by lettuce need to be determined in large-scale trials for commercial application. Efficacy and safety of ULO treatment for control of western flower thrips on broccoli.
3. Progress Report:
This is the final report for the project 5305-43000-003-00D. This project includes two parts: controlled atmosphere treatments and low temperature phosphine fumigation treatments for postharvest pest control on perishable commodities under Objectives 1 and 2. Under Objective 1A, head lettuce was found to tolerate ultralow oxygen (ULO) treatment for control of western flower thrips after they were stored for two or more days after harvest. Under Objective 1B, western flower thrips were successfully controlled on broccoli in a pallet scale ULO treatment at a low temperature of 1C in 5 days without injury to product quality. Under Objective 1C, a one-day ULO treatment with 0.5% oxygen was found to be safe and effective in controlling black widow spiders on table grapes. Effective CA, treatment with ULO in combination with 50% CO2 was found to be safe and effective in controlling all life stages of grape mealybug on table grapes. Under Objective 1D, safe and effective ULO treatments were found to control all life stages of vine mealybug on grape rootstocks. The treatment can be an alternative to the current labor intensive hot water dipping treatment. Under Objective 2A, low temperature phosphine fumigation treatment for western flower thrips was developed and the treatment was safe to lettuce, broccoli, asparagus, and strawberries. A commercial scale refrigerated container fumigation trial was also conducted to determine feasibility of shipping container fumigation. Under Objective 2B, studies were conducted to determine effective treatments for controlling lettuce aphid and leafminer and safety to lettuce quality. Lettuce aphid was effectively controlled in a 3 day fumigation with phosphine at a high concentration. But the treatment also resulted in significant lettuce quality degradation. Under Objective 2C, studies were conducted to determine effective treatment to control mealybug eggs, and grape mealybug eggs were found to be very tolerant to low temperature phosphine fumigation. The most important accomplishment of this project, however, is the finding that oxygen enhances phosphine toxicity and development of oxygenated phosphine fumigation method. Oxygenated phosphine fumigation was found not only more effective against insects than regular phosphine fumigation but also less phytotoxic because of reduced treatment time and shorter treatment durations as compared with regular phosphine fumigation. We further demonstrated that some insects/life stages such as light brown apple moth eggs could not be controlled with regular phosphine fumigation but can be controlled with oxygenated phosphine fumigation.
Liu, Y-B. 2012. Ultralow oxygen treatment for control of western flower thrips, frankliniella occidentalis (thysanoptera: thripidae), on harvested table grapes. Journal of Asia-Pacific Entomology. 15:269-271.