No abstract

Phytosanitary treatments are used to disinfest agricultural commodities of quarantine pests so that the commodities can be shipped out of quarantined areas. Ionizing irradiation is a promising phytosanitary treatment that is increasing in use worldwide. Almost 19000 metric tons of sweet potatoes and several fruits plus a small amount of curry leaf are irradiated each year in 6 countries, including the United States, to control a number of plant quarantine pests. Advantages over other treatments include tolerance by most fresh commodities, ability to treat in the final packaging and in pallet loads, and absence of pesticide residues. Disadvantages include lack of acceptance by the organic food industries and logistical bottlenecks resulting from current limited availability of the technology. A regulatory disadvantage is lack of an independent verification of treatment efficacy because pests may be found alive during commodity inspection, although they will not complete development or reproduce. For phytosanitary treatments besides irradiation, the pests die shortly after the treatment is concluded. This disadvantage does not hamper its use by industry, but rather makes the treatment more difficult to develop and regulate. Challenges to increase the use of phytosanitary irradiation (PI) are cost, because commercial use has not yet reached an optimum economy of scale, lack of facilities, because of their cost and current inability to feasibly locate them in packing facilities, lack of approved treatments for some quarantine pests, and concern about the process by key decision makers, such as packers, shippers, and retailers. Methods for overcoming these challenges are discussed.

Phytosanitary irradiation (PI) treatments are promising measures to overcome quarantine barriers to trade and are currently used in several countries. Although PI has advantages compared with other treatments one disadvantage bedevils research, approval, and application: organisms may remain alive after importation. Although this does not preclude their use as a phytosanitary treatment, it does leave the treatment without an independent verification of efficacy and places a greater burden for assuring quarantine security on the research supporting the treatment. This article analyses several factors that have been hypothesized to affect PI efficacy: low oxygen, pest stage, host, dose rate, and temperature. Of these factors, the first is known to affect efficacy, whereas host and dose rate probably need more research. The International Plant Protection Convention considered several PI treatments for its international standard on phytosanitary treatments and did not approve some at first because of perceived problems with the research or the presence of live adults after irradiation. Based on these concerns recommendations for research and dealing with the issue of live adults postirradiation are given. Generic PI treatments are suggested.

No abstract

Ideally, integrated pest management should rely on an array of tactics. In reality, the main technologies in use are synthetic pesticides. Because of well-documented problems with reliance on synthetic pesticides, viable alternatives are sorely needed. Physical controls can be classified as passive (e.g., trenches, fences, organic mulch, particle films, inert dusts, and oils), active (e.g., mechanical, polishing, pneumatic, impact, and thermal), and miscellaneous (e.g., cold storage, heated air, flaming, hot-water immersion). Some physical methods such as oils have been used successfully for preharvest treatments for decades. Another recently developed method for preharvest situations is particle films. As we move from production to the consumer, legal constraints restrict the number of options available. Consequently, several physical control methods are used in postharvest situations. Two noteworthy examples are the entoleter, an impacting machine used to crush all insect stages in flour, and hot-water immersion of mangoes, used to kill tephritid fruit fly immatures in fruit. The future of physical control methods will be influenced by sociolegal issues and by new developments in basic and applied research.

No abstract

Abstract1 The potential of ionizing radiation as a disinfestation treatment for insects other than tephritid fruit flies is discussed. Radiation quarantine treatments are unique in that insects are not killed immediately but rendered sterile or incapable of completing development.2 The most tolerant insect stage to radiation is that which is most developed. Female insects, but not always mites, are sterilized with equal or lower doses than males.3 Insects irradiated with sterilizing doses usually have shorter longevities than non‐irradiated ones. Low oxygen conditions often increase tolerance to radiation.4 Insects in diapause are not more tolerant of radiation than non‐diapausing ones.5 Some pests of several groups, such as aphids, whiteflies, weevils, scarab beetles, and fruit flies, may be controlled with doses ≤ 100 Gy. Some lepidopterous pests and most mites require about 300 Gy. Stored product moths may require as much as 1 kGy to sterilize, and nematodes could need > 4 kGy.6 Even though application of irradiation to pallet‐loads of produce could mean that up to three times the minimum required dose is applied to the perimeter of the pallet, many fresh commodities tolerate doses required for quarantine security against many quarantined pests. Irradiation is arguably the most widely applicable quarantine treatment from the standpoint of commodity quality.

Non-uniform heating of fresh fruit caused by variations in radio frequency (RF) fields is a major obstacle in developing postharvest insect control treatments based on RF energy. A fruit mover was developed to evaluate possibilities to improve RF heating uniformity of large fruit, such as oranges and apples, in a 12 kW batch type RF system. This fruit mover provided a means to rotate and move fruit in water when subjected to RF heating. Parameters for moving and rotating fruit in the mover were selected based on consideration of vortex formation, foaming, damage to the fruit, and volume occupied by the fruit in water. RF heating uniformity of oranges and apples in the mover was assessed using an infrared imaging technique and direct temperature measurement with fiber-optic sensors and thermocouples. The results showed that, with rotation and movement of fruit, temperature uniformity in oranges and apples was significantly improved with less than 2.8 and 3.1• C standard deviations, respectively, after an average temperature rise of about 30• C in 7.8 min. The fruit mover can be used to develop a treatment protocol for disinfecting fresh fruit and to simulate industrial scale and continuous treatment systems.