Studies On The Biology, Ecology And Chemical Control Of Rhodococus Turanicus Archangelskaja

Rhodococus turanicus is one of main pests in forests and orchards, but a few studies have been madein its biology and ecology. This thesis focused on its biology, ecology, natural enemies and chemicalcontrol from2009to2012in Luntai county, with the goal of integrative control.1. The paper investigated and studied biology characteristics by investigating in the field andobservation indoor. The results showed that: R. turanicus occurred1generation one year, and overwinteredas the2-ndinstar nymph fixing on the1-6years-old branches on the apricot in Luntai, Xinjiang. There was aclose relationship between its appearance and apricot phenology, the local temperature. The nymphpopulation was largest and sustained for long time in the field. The biggest fecundity was3500. Thefecundity could be predicted by female body weight (Y80790X2+11.874). The egg developmentthreshold temperature was9.15±0.16℃；the accumulating effective temperature290.17±4.876Degreedays; The average hatching rate was91.3%. The nymph can move3~4m toward light, and attached to theback of leaves in making damage. The nymph move to the branches during the apricot defoliation, andmost chose the lower half part of the3~4years old branches to overwinter. The sex ratio was about1:2,camp bisexual reproduction.2. To determine the distributing pattern and the suitable sampling method of Rhodococcus turanicusoverwintering nymphs, adults and aestivating nymphs on apricot. Nearest neighboring method was used tostudy the distribution of overwintering nymphs, adults and aestivating nymphs. Five different samplingmethods were compared with the significant difference of overall average and error rate of samplingmethods. Results show that: the spatial distribution pattern of Rhodococcus turanicus overwinteringnymphs, adults and aestivating nymphs was aggregative distribution on apricot. Zigzag sampling methodwas the most reliable one for overwintering nymphs and adults; parallel method was the most reliable onefor aestivating nymphs.3. By systematic field surveys, constructing life table of R. turanicus nature population. After analysis,the results showed that larval stage and adult stage were the key stages in one generation; the nature naturaldeath was the main control factor in one generation. parasitic wasps were the main factors of adult stagemortality and influenced on the egg production. The survival amount of each stage had trended down. Thepopulation numbers of the next generation were about32times as many as the previous generation.Combined with the data of life table, g matrix of insect population, and then constructing the naturepopulation matrix model of R. turanicus.4. There were7predatory insects of R. turanicus in Luntai.They are (Hippodamia vanegata),(Coccinella undecimpunctata),(Chrysopa septempunctata),(Chrysopa Formosa),(Deraeocorispunctulatus),(Diaea suspiciosa),(Xysticus cristatus),(Blastothrix sericae) and (Metaphycus pulvinariae).(Blastothrix sericae) and (Metaphycus pulvinariae) are parasitical natural enemies. The parasitism rates of(Blastothrix sericae) to Rhodococcus turanicus were48.97%.And there were two obvious peaks in field.Blastothrix sericae had the longest-living time after feeding.5. Select the effective pesticides and perfect time to controlling R. turanicus. Bioassay and fieldcontrol effects on overwinter and oversummering nymph of R. turanicus were studied. Acetamiprid had thehighest activity on the overwintering and oversummering nymph, LC50were31.268and22.056mg·L-1inthe lab. In the spring experiment,14.6%Thiamethoxam+9.4%Lambdacyhalothrin could control more than99%oversummering nymph and5%Acetamiprid98.76%on the overwintering nymph. By trunk injecting25%Thiamethoxam200times and20%Imidacloprid50times, control effects on incubation period nymphwere90.46%and94.16%；92.51%and82.57%on oversummering fixed and feed period nymph after15days.5%Acetamiprid and20%Imidacloprid spring had best effect and controlling time on overwinteringnymph. Trunk injection control had best control effect on the incubation period nymph.