南昌地区灰飞虱的生活史、繁殖和越冬生物学特性

为了探明灰飞虱Laodelphax striatellus (Fallén)在南昌地区的生物学特性， 本研究在实验室和自然条件下系统调查了该虫的年生活史， 温度对其生长发育、 繁殖、 性比及翅型分化的影响， 及其越冬生物学。结果表明， 灰飞虱在南昌一年发生4~7代。在18~32℃， 卵的发育历期随温度升高逐渐缩短。若虫的发育历期在18~28℃随温度升高逐渐缩短， 但若虫的发育历期在30和32℃时显著长于28℃的发育历期（P=0.000﹤0.05）。越冬个体的若虫期为143~187 d。卵和若虫的发育起点温度分别为10.17℃和7.51℃。在室外， 7月中旬高温下孵化的第4代若虫的发育历期也明显延长， 显示了高温诱导的夏季休眠现象。在18~28℃， 产卵前期随温度升高而逐渐缩短， 当温度上升到30℃时， 其产卵前期比26和28℃下有所延长。产卵期在22℃最长， 30℃下最短。成虫在20~24℃下的寿命最长。在28℃下， 平均每雌产若虫量最大。不论在室内还是在室外， 雌雄比均接近1∶1。在18~32℃， 羽化的成虫均以长翅型占绝对优势。在自然条件下， 越冬代和第6代羽化的成虫以短翅型占优势， 其他各代仍以长翅型占优势。在自然条件下， 9月中旬孵化的若虫就有少量个体滞育越冬， 10月中旬后孵化的若虫全部进入越冬。越冬若虫的龄期为1-5龄。本研究为该虫发生的预测及有效防控提供基础资料。

Life history,reproduction and overwintering biology of the small brown planthopper,Laodelphax striatellus

To ascertain the biological characteristics of the small brown planthopper, Laodelphax striatellus (Fallén), in Nanchang, Jiangxi, East China, the annual life history, the influences of temperature on development and reproduction, sex ratio and its overwintering biology were systematically investigated under laboratory and natural conditions. The results showed that this species exhibit mixed voltinism from 4 to 7 generations per year. Between 18 and 32℃, and 18 and 28℃, the egg duration and the nymphal duration gradually declined with increasing temperature, respectively. However, the nymphal duration was significantly longer at 30 and 32℃ than at 28℃. The duration of overwintering nymphs ranged from 143 to 187 d. The lower development thresholds of egg and nymph were 10.17℃ and 7.51℃, respectively. In the outdoors, the developmental duration of the 4th generation nymphs hatched at high temperature of mid-July had significantly delayed, showing high-temperature induced summer quiescence. Between 18 and 28℃, the pre-oviposition period gradually shortened with increasing temperature; however, the pre-oviposition period was longer at 30℃ than at 26 and 28℃. The oviposition period was the longest at 22℃, and the shortest at 30℃. The mean longevity of adults was the longest at 20-24℃. The number of nymphs produced per female was the highest at 28℃. Under both laboratory and natural conditions, the sex ratio is close to 1∶1. Between 18 and 32℃, the number of long-winged adults (macroptery) was significantly higher than that of short-winged adults (brachyptery). In the outdoors, the number of the brachytery was significantly more than that of the macroptery in the overwintering generation and the 6th generation, whereas the number of the macroptery was significantly more than that of the brachytery in other generations. Under natural conditions, winter diapause had already occurred in some individuals that hatched in mid-September, and all individuals that hatched after mid-October entered winter diapause. This planthopper overwintered as 1-5 instar nymphs. This study provides the basic data for the prediction of L. striatellus occurrence and the effective prevention and control of this pest.