摘 要：
灰稻虱为华北稻区主要害虫之一,在天津地区每年发生4-5代,以第4代或第5代的3-4龄若虫在稻田沟边、荒地杂草、土缝、稻茬内越冬;10月中旬能出现第6代的卵期,但由此孵出的若虫至11月中旬相继死去,故第6代若虫能否安全越冬尚待进一步考查。各代的发生期间互相重迭。 当春天2月末越冬若虫迁到杂草上取食、活动;4月末羽化为成虫迁入返青麦田,并在麦田内繁殖第1代;5月末以羽化后第1代成虫转入秧田,6月初至7月初移到本田,9月中水稻收获后转到荒地或新麦苗上为害。 灰稻虱卵期平均5.5-19.5天,若虫有2-7龄,一般为5龄,各龄期随不同世代而异:平均第1龄期3.1-8.9天,第2龄期2.6-8.8天,第3龄期2.2-11.1天,第4龄期2.2-10.1天,第5龄期3.5-6.8天,第6龄期3.3天,第7龄期2.5天。成虫有长翅型及短翅型两类,在天津地区—般可见短翅型雌虫而短翅型雄虫却极为稀罕。短翅型雌虫的发生和温度及饲料有关:高温和以稗子、三棱草为饲料者,短翅型雌虫发生较多。不同翅型在不同时期的成虫其产卵量不同:长翅型成虫平均每雌产卵119.2粒,而短翅型为158.1粒。 灰稻虱在本田中的消长与水稻生育期中的温湿度有关:其发生高峰处于水稻抽穗期及乳熟期。下雨后,高温有利于灰稻虱的发生。 灰稻虱每年在大田中发生数量的多寡可能受当年7-9月份降雨量?
译 名：
STUDY ON DELPHACODES STRIATELLA FALLEN (HOMOPTERA,DELPHACIDAE) IN NORTH CHINA
作 者：
TSAI PANG-HWA;HWANG FU-SHENG;& FENG WEI-HSIUNG;FU YI-RONG & DONG QI-FBNG Institute of Zoology. Academia Sinica Rice Institute of Tientsin
摘 要：
Delphacodes striatella Fallen is one of the most important insect pests on rice inNorth China. According to the results observed in the laboratory during 1959—1961 atthe vicinity of Tientsin, it possesses generally 4—5 generations per year. The eggs of thesixth generation may occur. Though these eggs may hatch into nymphs but they dieeventually in the middle of November. It appears that the different generations areoverlapping one another. The overwintering stage is the 3—5 instar nymphs of the 4th or 5th generation. Inwinter these nymphs hid themselves among those weeds along the sides of the paddy-fields, streams and the rice stubbles, and migrate partly to the soil crevices about 0.5-1cm underground. This insect possesses a migrating habit during the development, such as the nymphsafter overwintering migrate to the weeds in late February, and the adults emerged fromthe overwintering nymphs migrate to the wheat field at the end of April and producethe first generation there. The adults of the first generation migrate then to the rice-field. When the rice is harvested in September, these insect migrate back to the weedsagain. The egg stage is in an average of 6.4—19.5 day. The nymphal stage has 2—7 in-stars, but generally with 5 instars. The first instar is in an average of 3.1—8.9 days,second instar 2.6—8.8 days, third instar 2.2—11.1 days, fourth instar 2.2—10.1 days,fifth instar 3.5—6.8 days, sixth instar 3.3 days, seventh instar 2.5 days. The adults may be classified into the long-wing type and short-wing type. But ac-cording to the observations made in the field during 1958—1961, very few of the maleadults are of the short-wing type in this area. The appearance of the short-wing typeadults is influenced by the weather and food supply. The higher temperature and thefeeding on Echinochlod crusgalli Beauv. are favorable to the appearance of the short-wing type. The number of eggs laid by each female are significantly different in both types ofadults. The female of long-wing type may lay in an average of 119.2 eggs, while ofthe short-wing type 158.1 eggs. In the paddyfield, the appearance of this pests is from early June to the first decadeof July. But the abundant season is from late July to the middle of September. Duringthe abundant season, the higher temperature after precipitation is favorable to the in-crease in number of the pest. According to the observations during years 1959—1961,however, the reduced precipitation and long lighting of July and August, in North Chinacondition, are probably the main factor to stimulate the autumnal outbreak of the pest.
