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The oriental fruit fly,Bactrocera dorsalis(Hendel)(Diptera:Tephritidae),is an imortant worldwide quarantine pest.Yunnan province,with its diverse climates and rich diversity of plants,suffers heavily from the oriental fruit fly and,has the worst fly damage in China.While highly effective traps and insecticide spray are applied to suppress field population density of the fly,the indetermination of the density of trapping devices as well as the height and time of spot spray results uncertain control efficiency.Excessive application of pesticides also leads to a number of problems such as pesticide residues and resistance of the fly.The study was conducted to serve as a reference for standardizing the management practice of the pest. Daily activities and spatial distribution patterns of the oriental fruit fly,were studied in two mango orchards in Yuanjiang,Yunnan,from early June to early July,2011.The fruit flies were hourly observed with methyl eugenol-baited traps and yellow sticky traps from 8:00 to 19:00,respectively.Population data were collected and their spatial distribution patterns were analyzed by some distribution parameters.The results showed that the dynamic model of the number of males captured was a two-peak curve with two peaks recorded at 10:00 and 16:00,and three troughs at 8:00,14:00 and 19:00.There is no linear relationship between daily activity of the fly and atmospheric temperature and relative humidity.The flight altitudes varied with time in a day and were influenced by rainfall.The catches near the ground(below 0.5 m) were greater than those near the branches(above 1.5m) in the morning and noon on the sunny days.Rainfall played negative role on the flight activity and resulted a sharp decrease of captured number of the flies.Most flies preferred staying on the back of leaves above 1.5 m rather than near the ground on the rainy days.The maximum number captured by yellow traps was on 4 meter height of eight-meter-tall mango trees and significantly fewer flies had been found above 6 meter from the ground.The spatial distribution pattern of males in mango orchard was aggregation type,which was partly due to their aggregation behaviors.While a few represent a pattern of partly uniform,most females tend to aggregated distribution,which was due to the environment factors. |
