龙眼角颊木虱的初步研究

龙眼角颊本虱．分布于中国的福建、广东、海南和广西．是龙眼新梢嫩叶的一种重要害虫。1982—1983年在福州进行了这项研究。成虫在嫩梢,芽和叶上吸食为害,若虫固定于叶背吸食并形成下陷的虫瘘。因此在叶面布满小突起,叶片变小．畸形扭曲．影响新梢的抽生和叶片的正常生长,且为龙眼鬼帚病的传播介体。一年发生3—5代．世代重叠．并有部分滞育种群。若虫共4龄．大多数群体一年3代,8月间2龄若虫停育,继而越冬。部分发生4代2龄若虫9月底停育。发育成第五代的个体仅占少数,以2龄若虫从11月底开始停育越冬。翌年3月下旬(旬均温14．8℃),大部分若虫开始活动．3月底多数若虫老熟．成虫羽化产卵见于4月上、中旬。4月下旬盛孵。越冬代成虫迄5月中旬陆续羽化完毕。第一至四代成虫出现期．5月底至6月下旬;7月上中旬;9月上中旬;10月上旬至11月上中旬。成虫盛发产卵期与龙眼抽梢期相吻合,叶片的营养状况可能影响若虫的发育,4—6为一年中虫口数量的高峰期。文章对于形态和生物学也有较为详细的记述。     

龙眼角颊木虱发生规律与防治的研究

1998年调查了泉州农校旧校园内龙眼角颊木虱发生情况,并进行了几种农药防治龙眼角颊术虱若虫的室内和田间药效试驻。调查得知,该虫在泉州年发生4—5代．世代重叠,以二龄若虫和少数一龄若虫在被害叶的虫洞内越冬。若虫在龙眼树上的分布是外部叶片多于内部叶片;南面叶片多于西北面叶片;幼嫩、浓绿的叶片多于老、黄的叶片。若虫发生总是与新梢抽发期紧密相连,一年有两个高峰期,第一高峰期主要为害春梢和早发的夏梢,第二高峰期主要为害秋梢。药剂试验结果表明,几种新型农药对龙眼角颊术虱若虫均有较好药效,且药力持续时间长,尤以1％喜洋洋2000倍液和0．6％灭虫灵4000倍液的药效更佳。     

橄榄星室木虱的生活史和种群消长动态的研究

本研究了莆田市延寿村的橄榄星室木虱的生活史和种群消长动态。结果表明,橄榄星室木虱在莆田地区一年发生8代,世代重叠。卵、若虫(1—5龄)、成虫在1年中有6个发生高峰期,以秋梢期为全年雌成虫产卵、若虫发生最高峰,夏梢期是成虫羽化全年最高峰。其田间种群数量消长与橄榄抽梢期有着极为密切的关系,每一次抽梢期都带来一个产卵高峰期和低龄若虫发生高峰期,每一次抽梢都使虫口数量急尉上升,并出现高峰,其间也带来一个很高的种群增长率,待到新梢定型老化(枝梢生长后期)又使种群数量明显下降,而低龄若虫的发生和高峰期的出现,一般比产卵滞后5—10d。     

大突肩瓢虫生物学及田间种群消长研究

大突肩瓢虫5ynonycha grandis(Thunberg)在云南开远1年发生4代,以成虫在蔗茎老叶鞘内越冬.日均温26.6～27.8℃下,卵期3～4天,幼虫期9～12天,预蛹期1天,蛹期4～5天,成虫产卵前期20～25天,1个世代历期37～46天;日均温24.5～25.5℃下,卵期5～9天,幼虫期14～21天,预蛹期1～2天,蛹期5～8天,成虫产卵前期25～30天,1个世代历期45～55天.(第4代)(越冬代)各虫态历期延长,全代历期长达250余天.成虫、幼虫均捕食甘蔗绵蚜.大突肩瓢虫田间种群动态:6月初开始在蔗田出现,8～10月种群数量明显增长,11月间形成高峰,12月开始越冬.     

黑刺粉虱及其天敌的研究

黑刺粉虱Aleurucamhus spiniferus Quaint．是柑桔、茶树等经济作物的重要害虫。福建一年发生4-5代,闽北、闽中发生4代,世代重叠。主要以若虫在柑桔等叶背越冬,越冬若虫于翌年2月间开始化蛹(伪蛹),4月间成虫羽化并产卵。各世代若虫发生期为第一代4月上旬至6月上旬;第二代6月中旬至7月下旬;第三代7月中旬至9月上旬;第四代9月中旬至翌年3月,11月进入越冬期。一年中以6-9月为发生为害高峰期。黑刺粉虱的寄生性天敌和捕食性天敌资源丰富,蛹期被寄生率甚高,对该虫的综合治理可以生物防治为主要措施。     

蔗网蝽生物学特性的研究

蔗网蝽是福建南部蔗区新发现的一种甘蔗害虫,在仙游蔗区年发生6代,以成虫越冬。在室内自然变温下饲养,日平均气温24.4℃时,卵期平均11.2天、若虫期14.7天、产卵前期5.2天、全世代历期共31.1天。成虫寿命20～30天。每雌产卵15～25粒,成虫飞翔能力弱。沿溪河岸蔗园及水田蔗为害较严重,在蔗田背风、背阳的一面,虫口密度较大。     

日本方头甲生物学、捕食效能和农药选择毒性

日本方头甲(Cybocephalus nipponicus)是盾蚧科害虫的重要天敌。福建沙县一年4-5代,世代重叠。以成虫越冬,平均温度24．8℃,一世代历期47．2天;27．7℃,为32．6天。捕食盾蚧科害虫9种,并具有嗜食矢尖蚧雄虫的习性。一只末龄幼虫日取食矢尖蚧雄虫20-30只。柴油乳剂,松脂合剂和氧化乐果对日本方头甲低毒。     

白翅叶蝉的生物学特性和防治适期

白翅叶蝉(Thaia subrufa Motschulsky)在浙江省东阳县,一年大部发生二代。第一、二代成虫分别于6月下旬至7月上、中旬和8月下旬至9月中旬盛发于早稻和双季晚稻,第二代成虫大部分越冬,少数早发的才能发生第三代。第一、二和三代卵历期分别为17—19、11—12和15一19天,若虫历期分别为19、16和24天。成虫4℃开始活动,10℃开始取食,15℃开始羽化和产卵。卵开始发育温度在20℃左右。成虫无孤雌生殖现象,产卵前期在第一、二代分别为23和17天,越冬成虫则长达6—8月之久。每雌产卵量以越冬代最高,以后各代急剧下降。越冬后成虫在4月下旬几乎全部集中于早、中稻秧田,产卵盛期在5月即早稻本田分蘗期。繁殖寄主仅限于水稻。 因白翅叶蝉具有这些生物学特性,所以防治适期为早季秧田。1964—1965年在东阳县早季秧田大面积防治结果,可减低早、中稻本田虫口90%以上,且能压低双季晚稻田的虫口密度。     

短刺刺腿食蚜蝇生物学特性的初步研究

1991-1993年,在福州郊区调查,短刺刺腿食蚜蝇Ischiodon scutelloris为该地区优势种,一年发生6-7代,有越夏年份发生6代,无越夏年份发生7代。主要以蛹在土壤中越冬和越夏,世代历期随温度高低而异,平均气温为16.6℃时,世代历期长达45.3天;平均气温28.2℃时,为21.1天。幼虫期平均捕蚜量可达278.5头,三龄幼虫食量最大,占幼虫期总食量的80%以上,食蚜蝇姬蜂是造成本区秋季短刺刺腿食蚜蝇种群数量下降的主要原因。     

枯叶蛱蝶Kallima inachus的生物学研究

枯叶蛱蝶在四川峨眉山海拔450～1200 m地带一年发生3代,以第1代和第2代为主,以滞育成虫越冬.第2代成虫大部分在7月中旬后进入滞育状态,但3个世代的个体都可能存在于越冬种群中.在室内饲养条件下,第1代历期约为45～54天,第2、3代历期较长,越冬个体可达5～7个月.在日平均温度26.4～28.2℃,相对湿度63.2% ～84.7%条件下,卵期4～6天,幼虫期21～36天,蛹期10～15天.其寄主包括爵床科马兰属等多种植物.主要天敌有赤眼蜂、蜘蛛、蚂蚁和鸟类.     

大猿叶虫龙南种群的生物学特性

系统研究大猿叶虫Colaphellus bowringi Baly江西龙南(24°9′N,114°8′E)种群生物学特性。结果显示,该虫仅在春季和秋季发生为害,以成虫在土中越冬和越夏。由于成虫滞育期的差异,该虫显示出生活史多样性,有些个体隔年繁殖;有些个体是一化性,仅在春季或秋季繁殖1代;有些个体是二化性,在春季和秋季各繁殖1代;有些个体是多化性的,春季1代,秋季2~3代,因此,在田间1年可发生1~4代。春季,滞育成虫于2月中旬至4月初陆续出土繁殖,羽化的成虫于4月上旬至5月中旬陆续入土越夏;秋季,滞育成虫于8月中旬至10月中旬陆续出土,羽化的成虫于9月中旬至12月中旬陆续入土越冬。成虫一生能多次交配,在25℃下,春季世代雌虫产卵期为8~29d,平均产卵量为776粒;秋季世代雌虫产卵期为9~39d,平均产卵量为1003粒。各虫态的发育历期:在18~28℃间,卵为8.66~3.85d,幼虫为19.37~7.92d,蛹为8.57~3.41d。卵、幼虫和蛹的发育起点温度分别为10.5、11.5和11.9℃。滞育成虫的寿命为5~28个月。     

大猿叶虫生活史的研究

大猿叶虫Colaphellus bowringi是江西山区十字花科蔬菜上的重要食叶害虫,以成虫在土中越夏和越冬。由于成虫滞育期的差异,该虫的化性显示了明显的种内变异。有些个体隔年繁殖;有些个体是一化性的,仅在春季或秋季繁殖1代;有些个体是二化性的,春季和秋季各繁殖1代;有些个体是多化性的,春季1代,秋季2～3代。因此,大猿叶虫在田间一年可发生4代。在春季,滞育成虫于2月底至4月初陆续出土繁殖;在秋季,滞育成虫于8月中旬至10月初陆续出土繁殖。春季羽化的成虫于4月底至6月上旬陆续入土越夏,秋季羽化的成虫于9月中旬至12月底陆续入土越冬。大猿叶虫一生能交配多次,大多数雌虫的产卵期超过1个月,最长达67天。平均每雌产卵量：春季世代为644粒,秋季世代为963粒,最高达1.950粒。各虫态的发育历期：在15～30℃间,卵为13.78～3.14天,幼虫为22.83～6.95天,蛹为12.10～3.18天。发育阈值温度：卵为10.7℃,幼虫为8.8℃,蛹为9.6℃。非滞育成虫的寿命约为1～2个月,滞育成虫的寿命为5～38个月。滞育成虫均入土蛰伏,在土中的蛰伏深度为9～31 cm 。     

Density and structure of Saissetia oleae (Hemiptera: Coccidae) populations on citrus and olives: relative importance of the two annual generations

Saissetia oleae (Olivier) (Hemiptera: Coccidae) populations were studied and compared in citrus (Citrus spp.) and olive (Olea europaea L.) groves to determine the number of generations, crawler emergence periods and changes in population density during the year. Ten citrus and four olive groves were sampled regularly between March 2003 and December 2005 in eastern Spain, covering an area of 10,000 km2. Each sample consisted of 16 branches and 64 leaves. Saissetia oleae populations presented a similar trend in both crops during the three years of study. Populations peaked in July, when crawlers emerged after the egg-laying period, and decreased during several months due to mortality of first instars in summer. A second crawler emergence period, with lower numbers and more variability from year to year, occurred between October and March. Populations did not increase during this period, probably because most eggs and crawlers perished during the winter and also because females that gave rise to this fall-winter generation were half as big and fecund as spring females. No differences were found between the size of mature females that had developed on citrus and on olives during the spring. Considering this population pattern, the best seasonal period to apply pesticides to control S. oleae would be at the end of July, when populations are synchronous, all crawlers have already emerged, and first instars predominate.     

The population dynamics, reproductive strategy and life history tactics of Musculium lacusfre (Bivalvia: Pisidiidae) in Hong Kong

Hitherto uninvestigated in Hong Kong are the population dynamics, reproductive strategies and life history tactics of the Pisidiidae of which three species are known to occur locally. This study is of Musculium lacustre inhabiting a drainage ditch of the Lam Tsuen River in the New Territories of Hong Kong and extended over 15 months during 1983–84.
In Hong Kong, M. lacustre is a protandric, simultaneous hermaphrodite that matures at a length of 2 mm; the majority of each generation is, however, not mature until a length of between 4–6 mm is attained. Fertilized eggs are brooded in the inner demibranchs until they reach a length of 1.5 mm when they are released as post-foetal larvae. Musculium lacustre is univoltine. Reproduction occurs twice a year but, since M. lacustve is semelparous, the population contains, at any one time, two overstepping generations. Thus, a spring generation is recruited and grows rapidly to generate a second, smaller, autumn generation. This in turn grows rapidly and matures to produce the spring generation of the succeeding year. Adult mortality occurs in late summer and winter. A few of the late-born spring generation may overwinter to contribute to the spring generation of the succeeding year. This is not so with the autumn generation.
Such sexual and life history tactics can be related to the climate and hydrology of Hong Kong and its freshwater habitats. Reproduction takes place in spring and autumn when temperatures are moderate. Mortality is high in summer and winter when the habitat is either, respectively, hot and flushed out by summer rains or cold and dry. As M. larustre is able to overwinter but not aestivate at these latitudes (22° N), it is postulated that this holarctic species is approaching the southern limit of its asiatic range. Musculium larustre is compared with the other bivalves inhabiting fresh and brackish-water habitats in southern China.     

苹果黄蚜、苹小卷叶蛾发生规律和分布型的研究

研究了苹果黄蚜和苹小卷叶蛾在山东省烟台地区的发生规律,它们一年分别发生13～14代和3代。苹果黄蚜的种群一年出现两次高峰．这与苹果树春、秋梢的2次生长规律相符合。测定了苹果黄蚜和苹小卷叶蛾幼虫在苹果树上的分布型,均属聚集分布,分析提出了适宜的取样调查方法．     

Investigations on the gout fly (Chlorops pumilionis Bjerk.) in Devon and Cornwall

Field observations from 1943 to 1946 on attacks by gout fly on wheat in south-west England show that there are two generations of the fly during the year, the first emerging in May from October-laid eggs and the second emerging in late July and early August. The first generation severely damages spring wheat and may also attack very late sown and backward autumn wheat; wheat not above ground before 20 October escapes attack by the second generation. In south-west England, the optimum period for drilling wheat to escape gout-fly damage is mid-October. In this area, both generations of gout fly show a marked preference for wheat; attacks on barley are negligible.     

Life-cycle characteristics of Tetrastichus turionum, a parasitoid of the European pine shoot moth, Rhyacionia buoliana

Abstract:  The life cycle of Tetrastichus turionum , a pupal endoparasitoid of the European pine shoot moth Rhyacionia buoliana , was studied in Spain in the field, prior to its use as a potential biological control agent of this pest in Chile. T. turionum showed two generations acting on the same host generation. Adults from the overwintering generation emerged and dispersed from mid- to late spring and gave rise to a fast developing, current year generation. Adults of this generation emerged and oviposited in early to mid-summer, producing progeny that overwintered as fourth instar larvae inside their host. Both generations appeared highly synchronized to the presence of pupae in the host population. The role of decreasing day length in the induction of diapause is also discussed. Laboratory bioassays showed that T. turionum did not oviposit on R. buoliana larvae already parasitized by Orgilus obscurator , a major larval parasitoid, already introduced in Chile. The results reinforce the suitability of T. turionum as a promising parasitoid that would complement O. obscurator in the biological control of European pine shoot moth.     

Shoot growth dynamics and size-dependent shoot fate of a clonal plant,Festuca rubra, in a mountain grassland

The relation of the within-season and between-season patterns of shoot growth were compared in a clonal grass with long-lived shoots,Festuca rubra, in a mown mountain grassland. The growth rate of shoot length from spring to summer in a year was almost constant for each shoot irrespective of spring shoot length each year. The annual shoot growth rate from spring to spring was negatively correlated with the shoot length in the first spring. Shoots of different length and age therefore tended to converge over time to a population of identical shoot size, suggesting an equalizing effect of growth pattern on size structure. Shoot size (shoot length and number of leaves) influenced the fates of shoots. Larger shoots showed an increased incidence of both flowering and formation of intravaginal daughter shoots and a decreased incidence of death in the subsequent time period. The fates of shoots were independent of their age. Although the negatively size-dependent springto-spring annual shoot growth rate acted to decrease shoot size variation, the remaining variation within the shoot population was still sufficient to generate different fates of shoots. These fates were not related to the previous life history of individual shoots. There was a significantly positive effect of the shoot size at initiation on its life expectancy. This was mainly attributable to the positively size-dependent survival rate of shoots in the early stage (<1 year old) of shoot life history. Later on (> 1 year old), shoot size had little effect on the survival rate of shoots. Once small young shoots have survived this early stage (< 1 year old) in life history, they can grow vigorously, little affected by competition regardless of shoot size, and converge to a stable size structure of shoots of similar size. Only shoot size in the early stage ( < 1 year old) of life history is important for the persistence of a shoot population.     

Phenological dynamics of Dasineura mali (Diptera: Cecidomyiidae) and its parasitoid Platygaster demades (Hymenoptera: Platygasteridae) in apple orchards

The midge Dasineura mali Kieffer (Diptera: Cecidomyiidae) is an important pest of apple (Malus domestica Borkh.) and a potential fresh fruit contaminant, causing quarantine concerns. The phenological dynamics of D. mali and its egg parasitoid Platygaster demades Walker (Hymenoptera: Platygasteridae) were studied in the field in Palmerston North, New Zealand, for 2 yr. Both shoot infestation rate by D. mali and D. mali density per shoot sharply increased in the second generation, reaching approximately 65% and 100-200 eggs, respectively. However, although the infestation rate in the third generation remained as high as in the second generation, the pest density per shoot significantly decreased to 40-60 eggs in the third generation. In the fourth generation, both infestation rate and pest density per shoot decreased to approximately 30% and 10 eggs. Due to the simultaneous decline of the apple shoot number and D. mali density in the third and fourth D. mali generations, the absolute number of D. mali in the orchard also has declined proportionally during the same period. The parasitism and superparasitism rates significantly increased as the season progressed, from 45 to 55 and 37% in the first generation to 87 and 82% in the fourth generation, respectively. Our results suggest that P. demades contributes to the continuous decline of D. mali numbers in the field; it is a good searcher, particularly when its hosts become increasingly scarcer over the season, and it avoids overshooting the host population later in the season by increasing superparasitism. The frequency of P. demades aestivation increases from late spring to midsummer and then decreases during the late summer and early autumn. Although the emergence of P. demades was approximately 2 to 3 wk behind that of D. mali in each generation, the increasing parasitism rates from the first to the fourth generations indicate that P. demades is synchronized with D. mali in the field.