Research On The Heat Treatment Of Two Quarantine Mealybugs

Pseudococcus jackbeardsleyi Gimpel et Miller and Planococcus minor(Maskell), bothinsects with quarantine importance because of they wide range of economic hosts andits ability to expand its geographic range. With the increase in international trade inrecent years, they is an important quarantine insect pests in the world, It has a widehost range and hige reproducibility, it will bring devastating damage to the local cropsuch as fruits and vegetables when it colonizes, the cropt quality and output will bedecreased, the normal production and living of people and the whole industrydevelopment will be seriously influenced, so it is necessary to strengthen thequarantine treatment. Jack Beardsley mealybug, Pseudococcus jackbeardsleyi Gimpelet Miller and Planococcus minor (Maskell) were respectively treated with forced hotair treatment and hot water immersion under a series of time to observe the mortalityof both pests. Papaya sensory evaluation and quality are monitored after heattreatment. The research demonstrates that FHAT and HW could provide quarantinesecurity for controlling of both mealybugs on shipped commodities.1. All the developmental Jack Beardsley mealybug stages were respectivelytreated with forced hot air treatment (FHAT,49℃90%RH) and hot water immersion(HW,49℃) under a series of time to observe the mortality ofP. jackbeardsleyi, Theresults showed that the estimated lethal time to99.9968%mortality (LT99.9968) foreggs under FHAT. The tolerance to heat increases with increasing ages anddevelopmental stages, and female adults are determined to be the most tolerant stage.In the hot water immersing the eggs, which are closely tolerant with female adults, aredetermined to be the most tolerant stage. The reason for the changes in heat toleranceof P. jackbeardsleyi eggs response to FHAT and HW was discussed. the ThermalDeath Kinetic Model was used to analyze the relationship between mortality andheating time for the comparison of the tolerance to heat. In the forced hot airtreatment at45,47,49and51℃, LT99.9968of female adults was253.41,118.17,98.75,and63.17min.In the forced hot air treatment at45,47,49and51℃, LT99.9968offemale adults was60.03,29.15,and9.59min, LT99.9968of eggs was60.03,29.15,18.60, and9.59min.2. Planococcus minor(Maskell) life stages (adult females, nymphs and eggs) were tested for their susceptibility to hot water immersion at47,and49℃, for the mosttolerant stage and the most optimal dose to control mealybugs. Hot water immersionat47, and49℃, required38min18min kill all thePlanococcus minor. Lethal timeestimations were calculated and using a probit model for find the stage of most heattolerant. Eggs inside ovisacs were the most heat tolerant at49℃by hot waterimmersion. In the hot water immersing at47,and49℃, LT99.9968of eggs was58.82min,29.09min. Results from this study provide efficacious temperature-timetreatments.3. Heat treatment is a widely used postharvest technology, which carries outprimary products preservation and kills pests and microorganisms. In our study,papaya fruits were treated by forced hot air treatment in47.2oC for30,60and90minto test their sensory evaluation and quality during0,4,7and10day. Sensory scoreand quality was used to evaluate fruit quality of papaya. we found heat treatment(from30to90min) increased quality of papaya fruits and extended their shelf life.After10days store, comprehensive score in49oC90min treatment was the highest inall treatments. Results also showed that the scores of texture in90min heat treatmentwere significantly higher than the scores in control treatment. Heat treatment has littleeffect on papaya fruits quality.The fruit quality slightly decreased with the extensionof storage time, its incorporate is: the weight loss was increased, the contents ofsoluble solid, titrable acids was decreased...