Studies On The Population Ecology Of Panonychus Citri(McGregor) On Citrus Aurantium

Citrus aurantium is one of the famous genuine medicinal materials in Jiangxi Province,which is listed as the national geographical indication protection product.In recent years,due to the large planting area and high density,the pest species of C.aurantium are gradually increasing,among which Panonychus citri（McGregor）is the most serious,causing serious economic losses.This research systematically explored the growth,development,reproduction,occurrence and distribution patterns of the experimental population of P.citru on C.aurantium,and the pathogenicity of Beauveria bassiana to P.citru,in order to control P.citru.The occurrence and damage of mites provide a theoretical basis,and the main results are reported as follows:1.The effect of temperature on the development period of P.citru:within the range of 16-32℃designed in the experiment,the development time of each mites of P.citru mites reared on C.aurantium leaves gradually decreased with the increase of temperature;The developmental starting temperature of P.citru during the entire growth and development period is 8.16℃,and the effective accumulated temperature is 213.03 days;among the various mite stages,the developmental starting temperature and effective accumulated temperature of the egg stage are the highest,respectively 9.36℃ and 92.53 days;The starting temperature and effective accumulated temperature of the nymphs were the lowest,which were 8.19°C and37.17 degrees Celsius,respectively.2.The establishment of the life table of the experimental population of P.citru:Within the experimental temperature range（16-32℃）,the egg production of P.citru as the feed showed an upward trend and then a downward trend;The egg production at 16℃was the lowest at 0.9 eggs/day,and the highest egg production peak at 28℃ is 3 eggs/day;in addition to the number of eggs laid,the spawning period and average daily egg production also show the same trend and reach at 28℃ The highest value（10.46 days and 3.14）;the net value-added rate of the experimental population（R₀）showed a trend of first rising and then falling and reached the highest peak at 28℃;the intrinsic growth rate m_r,periodic growth rateλand other parameters all increased with the increase in temperature Increase;the average generation period and population doubling time both decrease as temperature rises.3.Spatial distribution pattern of P.citri:according to the aggregation index,Taylor power law and iwaor regression analysis,it was concluded that P.citri had an aggregation distribution on C.aurantium.The optimal sampling number was N=3.75+24.825/x.The population dynamics of P.citri on C.aurantium in one year had two peaks,which were from June to July and from October to November,with June to July as the main peak.4.Research on the pathogenicity of B.bassiana to P.citru:Experiments show that under the same conditions,the mortality of P.citru feeding on C.aurantium increases with the concentration of B.bassiana spores.The highest peak was reached when the concentration was 10⁸spores/mL,and the highest cumulative mortality of P.citru on the citrus fruit was 92.98% for 7 days.