Radar Observations Of Meadow Moths Occurrence And Forcasting Investigation

The meadow moth (Loxostege sticticalis L.), in the family Crambidae, is a worldwide pest that ismainly distributed in arid areas of the northern temperate regions. It is one of the most serious migratorypests in the northern farming and pastoral areas of China. Ascertaining its patterns of migration andpopulation expansion and tracking the routes by which it enters China from neighboring nations couldprovide a scientific basis for forecasting the moth's movements and effectively controlling thiseconomically damaging pest. During2010and2011, we carried out a long-term monitoring of the pestaround the western suburbs of Xilinhaote City, Inner Mongolian Autonomous Region of China.Thestudy included: the use of a vertical-looking radar (VLR) combined with a searchlight, light-trapping onthe ground, assessing the ovarian developmental status of female moths captured at the light traps atdifferent periods, estimating the source areas of the second generation of meadow moth by backwardcalculating their trajectory, and analyzing how the atmospheric circulation patterns influenced theirmigrations.The VLR echoes during2010and2011appeared that: the meadow moth populations(overwintering,the first generation and the second generation) mainly at a height of300–400m. Thepeak in the pastoral areas is later than in the farming areas, mainly between0:00–5:00am. The resultsof this study showed that the meadow moth from the pastoral areas had the features as following duringthe migration peak:(1) The migration peaks of the overwinter and the first generation meadow moth arerelatively short, and the migration peaks of the second generation are relatively long. There were twomigration peaks of the first generation meadow moth in2010, the first was from1July to6July and thesecond was from10July to21July, The migration peaks of the first generation meadow moth in2010was from22June to30June, relatively short; While the migration peaks of the second generation arerelatively long, The migration peak in2010was from8August to21August and from26July to23August in2011, all lasted nearly a month.(2) The amount of the meadow moth trapped in the peak dayis great. The migration peak day of the second generation meadow moth in2010was11August and theamount was9167one day one light; There were few peaks day of the second generation meadow mothin2011, we trapped75560moths on26July and20652on1August.(3) The uprush and the anticlimaxof the meadow moth amount is obvious. Particularly in the second generation meadow moth, the amoutof the meadow moth trapped in the light was75560, but only61in the previous day (25July) and277in the next day (27July); the amout of the meadow moth trapped in the light was20652, but only107inthe previous day (31July) and34in the next day (2August).(4) The ovaries of the female meadowmoths are developping in low grade. There were five migration peaks of the meadow moth during2010to2011, Check the ovaries of the female meadow moths and the results show that they were mainly indevelopmental stage I or II.The trajectory analysis of the migrations showed that the source of the overwinter generationmeadow moth come from norheast of Inner Mongolia, this is one case study that the meadow moth source in our Country influence the meadow moth overseas. The first generation in the pastoral areasmainly come from Mongolia, the source of the meadow moth during1July to6July and10July to21July in2010came from the middleeast and northeast of Mongolia. The second generation in the pastoralareas mainly come from Mongolia, the source of the meadow moth during from8August to21Augustin2010and26July to4August in2011came from the middleeast and southeast of Mongolia;Neverthless, The source of the second generation in the pastoral areas also can come from our Country,such as the source on23August in2011was from the west of Xilinguole.West Pacific Subtropical High in East Asia and Siberia low pressure are very important to themigration of the pastoral areas of China, after the third leap of West Pacific subtropical high, stable at25–30°N, the northern boundary is located35–40°N, between the northwest side of the activesouthwesterly airstream over the northern pastoral areas of flow field plays a very important role. TheCold high-pressure or ridge as well as cyclones, fronts, trough or frontal cyclone atmospheric are veryclose to meadow moth immigration and landing.The rainfall is close to the taking-off, landing of the meadow moth. This study showed that duringall5migration peaks of meadow moth, always associated with the rainfall. The meadow moth uprushin July and August2010, June2011and two days(26July,23August) during the migration peaks ofsecond generation meadow moth in2011all begin after the rainfall.