Hot water treatment and insecticidal coatings for disinfesting limes of mealybugs (Homoptera : Pseudococcidae)

Hot water immersion and insecticidal coatings were tested to determine if t hey could be used to disinfest Persian limes, Citrus latifolia Tanaka, of t he mealybug pests Planococcus citri Risso and Pseudococcus odermatti Miller & Williams. A 20-min 49 degrees C hot water immersion treatment is effecti ve in killing mealybugs and all other arthropods tested found externally on limes, or under the calyx. No insects or mites were found to survive after the 20-min hot water treatment. In this test, 7,200 limes were treated wit h 1,308 insects killed and zero survivors. Treatment at 49 degrees C for 20 min did not significantly affect quality when treated fruit were compared with untreated control fruit. Four coatings were tested at a 3% rate: two p etroleum-based oils (Ampol and Sunspray oil), a vegetable oil (natural oil) , and a soap (Mpede). The coatings gave up to 94% kill (Ampol) of mealybugs , which is not sufficient to provide quarantine security. The coatings migh t be effective as a postharvest dip before shipment.