河北省南大港农场2002年夏蝗发生特点及原因浅析

进入 90年代以来 ,南大港蝗区东亚飞蝗Locustamigratoriamanilensis(Meyen)大发生 6次 ,2 0 0 1年夏秋蝗发生面积达 2 6万hm2 ,5龄蝗蝻最高密度为 1 0 0 0 0头 m2 。 2 0 0 2年形势更为严峻 ,仅夏蝗发生面积超过 2万hm2 ;分别造成 1 3 0 0hm2 和 2 70 0hm2 的芦苇被吃成光杆和被啃食的严重破叶。出土时间早、孵化时间长、龄期悬殊大是今年夏蝗发生的主要特点。主要原因是去年越冬卵块基数大 ,其次是受气候条件和农业环境的影响

Reasons and characteristics of outbreak of oriental migratory locust Locusta migratoria manilensis in Nandagang, Hebei Province

Oriental migratory locust Locusta migratoria manilensis (Meyen) have continually broken out six times in Nandagang since 1991.The number of five instar nymph reached 10 000/m 2 and occurrence areas exceeded 26 000 hm 2 in 2001.But the situation of this year 2002 is more serious. Reed areas damaged by only summer locust have overtook 20 000 hm 2 and 4 000 hm 2 repectively before June. Hatching earlier but continuing longer time is chief characteristics of summer locust this year. The major reason for outbreak is that there is much more overwintering eggs in 2001, reaching 66 patches/m 2 , which affects directly the degree of occurrence of summer locusts this year. The second reason is the influence of climate conditions and changeable agro\|environment.