Postharvest disinfestation treatments for deciduous and citrus fruits of the Western Cape, South Africa: a database analysis

E FFECTIVE POSTHARVEST DISINFESTATION of export fruits from the Western Cape province of South Africa would help to reduce rejections due to the presence of insects. However, there is normally only a limited opportunity between controlling the insects and damaging the produce. A widely used agent in disinfestation procedures, methyl bromide, was scheduled to be withdrawn in many countries in 2005 due to its ozone-depleting properties. The main alternatives are irradiation, extreme temperatures, forced air, vapour-heat methods and the use of controlled atmospheres. A literature survey was used to identify postharvest treatments with the highest likelihood of success in killing insect contaminants without damaging the fruit. Data from 284 scientific articles relating to these kinds of disinfestation were entered into a database (PQUAD). Queries were run to determine the most intensively studied fruits and pests. The tolerances of the commodities were compared with those of the pests at family level. Where pest tolerances were lower than those of the fruit, the treatment was regarded as a possible candidate for use. Methyl bromide, controlled atmospheres and irradiation were identified as the most widely used against pests. Irradiation appeared to control insects at doses that did not damage deciduous produce. Citrus appeared to be more susceptible to damage, however, than deciduous fruits. Low temperature also seemed to be less detrimental to deciduous fruit than to citrus. Deciduous fruit is already preserved in cold storage, making this an inexpensive option to combat insects. Cold treatment appeared to control members of the Pseudococcidae, Tephritidae and Tortricidae; more work is required on the other pest families. Controlled atmospheres also had a high chance of success for both citrus and deciduous fruits.