Quarantine Treatments and Systems Approach to Quarantine Security Robert L. Mangan Crop Quality and Fruit Insect Research USDA-ARS, Weslaco, Texas, USA

Quarantine Goal Prevent undesirable pest introduction Allow transport of commodities

Importance of Quarantine Treatments Access to Markets for Fruits and Vegetables Industrial nations need more variety in diet and improved nutrition

Quarantine security confidence that there will be no pest introduction capable of reproduction in an imported commodity

Fruit Flies introductions are usually by transport of fruit with immature insects immature stages are usually clustered in fruit probit 9 requirement was devised to account for this clustering (Baker 1939)

Probit 9 (as applied to quarantine of insects) 95% confidence that less than % of treated insects will survive

Historical Development of Systems Approach Withdrawal of quarantine treatments –Ethylene dibromide 1984 –Methyl bromide phase-out 1992-present No acceptable quarantine treatments –Cost, damage, new commodities Questionable need for quarantine treatments –Infestation very rare –Production and marketing system meets quarantine requirements

…the integration of those preharvest and postharvest practices used in production, harvest, packing and distribution of a commodity which cumulatively meet the requirements for quarantine security. E. B. Jang and H. R. Moffitt (1994)

Components of a Systems Approach Jang and Moffitt 1994 vs ISPM 14 Production Preharvest treatments Postharvest treatments Inspection and Certification Marketing and Distribution Pre-plant Pre-harvest Harvest Post-harvest treatment and handling Transportation and distribution

Pre-harvest vs Post-Harvest Treatments Pre-harvest treatments that control the pest usually reduce the number of fruit infested but not the number of pests per infested fruit. Post-harvest treatments usually kill individual pests in the fruit thus reducing the number of pests per fruit.

A. ludens infesting Mangos- Baja CA. 1992

Frequency Distribution – A. ludens in Oranges Baja Ca. Sur 1992

Perform “dose - response tests” Statistically determine treatment that will achieve required mortality

Confirmatory Tests Confirm effectiveness of propose treatment under conditions similar to commercial use. Data must be analyzed statistically to demonstrate confidence that required mortality level is achieved. Precise methods used in confirmatory tests must be approved by importing country.

Experimental Hot Forced Air Unit USDA ARS Weslaco Texas

Experimental Unit Hot Water Treatment

Heat Treatments

Experimental Units Modified Atmosphere/Heat Treatments

Radiation Treatments Screwworm Sterilization Kerrville Tx ? Fruit Irradiation Moore Airbase USDA PPQ

Commercial Radiation Treatment Hilo Hawaii

Fumigation Treatments

Commercial Hot Forced Air Chamber Montemorelos Mexico

Dose-Response Treatments Controlled Atmosphere Pupal survival drops fastest at days treatment. Variability is highest below 12 days.

AtmosphereExposure (hours) Adjusted Average z Dead Larvae Air ± 4.4 1% Oxygen ± ± ± ± 0.0 Number of Dead A. ludens Larvae after Exposure to 46°C Z. Grapefruit artificially infested with 25 live, 3rd instar larvae

Radiation Dose-Mortality Pupae Anastrepha obliqua Hallman 1997 Mortality is sigmoid- maximum chnge in survival at 5->10 g. Variance in mortality is highest at 50% mortality.

Advantages of Post Harvest Quarantine Treatments Mortality is known from dose-response and confirmatory tests. Mortality rate is independent of other systems approach factors. At appropriate doses, variability in the system can be greatly reduced.

Product Quality Certain yellow varieties of mangoes, immature tissue converts starch to fibrous material in place of sugar. Temperate Fruits: more sensitive to heat treatments

Summary and Recommendations The systems approach was developed in as an alternative to post harvest quarantine treatments. Operation of post harvest treatments is independent of production, and marketing conditions, can be monitored at treatment facility and provides a known level of pest mortality. Post harvest treatments treat individual pests infesting the commodity and reduce variation in infestation rate per commodity. Many post harvest treatments for other purposes such as hot water dips for disease control, cold storage and controlled atmosphere for shipping and radiation for sanitation cause high pest mortality and should be considered as systems approach components.