Published online by Cambridge University Press: 17 October 2014
Introduction. Timing of management practices requires anunderstanding of pest population dynamics in given cropping systems. Our study wasdesigned to establish the population trends of B. invadens in mangoorchards and to determine if population fluctuations were reflected in fruit infestationlevels during changes in mango phenology. Materials andmethods. Bactrocera invadens flies were trapped weekly fromFebruary 2011 to November 2012, using methyl eugenol and DDVP (dichlorvos) insecticidalstrips. Trapping was done in three mango orchards in the Luweero district of Uganda’s LakeVictoria Crescent. Mango fruit samples were incubated for the retrieval of puparia tocalculate positivity (proportion of fruits infested) and fruit infestation indices (numberof puparia per kg of fruit) for each stage of fruit maturity. Results. Meantrap catches of adult B. invadens varied significantly over the months(range : ~11 flies per trap per day (FTD) to over 590 FTD; P £ 0.0001).During each year, infestations peaked during June-July and January-February. Trap catcheswere higher in the major fruiting season compared with the minor fruiting season and werethe highest when mango was at the physiological maturity and ripe stages. Fruitinfestation and positivity were highest for fruit at the physiological maturity and ripestages and lowest at the fruit set stage. Discussion. Our findings show thatB. invadens is present year-round and all stages of mango fruitdevelopment are susceptible to attack. Thus, control measures should be implementedthroughout the year and preferably started at fruit set to lessen fruit fly populationbuild-up and damage to fruits.