小菜蛾幼虫对菜心叶片取食量的测定及其拟合模型

通过小菜蛾Plutella xylostellaL.幼虫对菜心取食量变化的研究,得知小菜蛾幼虫在不同阶段的取食量以及变化规律,累计取食量在一定程度上表明了害虫的某一发育阶段对寄主的危害程度.并根据小菜蛾幼虫取食量与时间关系使用SAS 8.1和Matlab 7.1软件进行曲线拟合.小菜蛾幼虫取食菜心的叶面积的拟合曲线为f...     

虫害诱导的植株对小菜蛾取食和生长发育的影响

本文从菜田生态系统的角度出发,就黄曲条跳甲Phyllotreta striolata(Fabricius)取食诱导对小菜蛾Plutella xylostella(L.)造成的影响进行了研究。黄曲条跳甲取食诱导对小菜蛾取食的影响比较明显,一般来说,黄曲条跳甲少量或短时间的取食会刺激小菜蛾幼虫在相应叶片上的取食,反之则会抑制;而且不同的寄主,不同完整度的叶片(即是否被黄曲条跳甲取食过)上的承载能力不同,芥菜、白菜、菜心和萝卜的承载力弱于甘蓝和芥蓝,黄曲条跳甲取食过的叶片弱于未被黄曲条跳甲取食过的叶片;不同数量的黄曲条跳甲取食对小菜蛾的产卵量影响显著,对其余生物学参数影响不显著,少量的黄曲条跳甲取食会刺激小菜蛾的产卵,多数则会抑制。     

亚麻荠对小菜蛾幼虫取食和成虫行为反应的影响

亚麻荠是一种很少有害虫危害的油料作物。用室内生测和Y 型嗅觉仪研究了亚麻荠对小菜蛾Plutella xylostella幼虫取食和成虫行 为反应的影响。以甘蓝作对照,用亚麻荠叶片喂养的小菜蛾初孵幼虫3天后校正死亡率为79 .2%,显示了较强的致死作用;喂养小菜蛾3龄幼虫至化蛹,其存活率、化蛹率、蛹重及成 虫寿命都显著降低,表明亚麻荠对小菜蛾幼虫的生长发育有不利影响。在幼虫的取食选择实 验中,有甘蓝叶供选择时,小菜蛾幼虫不取食亚麻荠;在无可选择的情况下,小菜蛾幼虫也 取 食亚麻荠叶片,但取食量很小,与取食甘蓝叶的量相比,差异极显著。行为反应测试表明, 小菜蛾成虫对甘蓝和亚麻荠植株的挥发物都有明显的趋性反应,与对照（净化空气）相比, 差异极显著,而在甘蓝和亚麻荠之间无选择性。说明小菜蛾成虫对亚麻荠植株的挥发物具有 较强的定向反应。     

小菜蛾取食对寄主植物蛋白质和糖含量影响研究

小菜蛾Plutella xylostella (L.)是重要的十字花科作物害虫,寄主植物体内营养物质的变化影响小菜蛾生长发育。本研究以小菜蛾嗜好性不同的菜心、芥菜、白菜和芥蓝等4种寄主植物为材料,应用生化方法测定了被小菜蛾取食后寄主植物体内蛋白和糖含量的变化。结果表明:小菜蛾取食2、4、6、8d后,菜心体内蛋白质含量显著升高2%～35%,葡萄糖含量明显下降9%～33%;芥菜、白菜和芥蓝体内蛋白质和葡萄糖含量显著下降1%～38%和3%～36%。小菜蛾取食后,白菜和菜心体内蔗糖含量显著升高,以菜心为害2d后升高最显著,达23.32%;芥菜和芥蓝则随为害程度的不同蔗糖含量略有差异。     

寄主胁迫下小菜蛾种群的RAPD分析

采用RAPD-PCR技术,研究了取食6种不同十字花科寄主植物第4、9、15代小菜蛾Plutella xylostella(L.)种群的DNA多态性。通过17条引物的重复PCR扩增实验,利用NTsys软件对电泳条带统计分析,构建了遗传距离矩阵和聚类分析图谱。结果表明:取食芥蓝的小菜蛾种群与其它5种寄主种群遗传距离较远(0.6523～0.8246),独立聚为一枝;取食萝卜的小菜蛾种群遗传距离与甘蓝上种群较近(0.3443),聚为一枝,并且与白菜、芥菜和菜心上小菜蛾种群遗传距离较近,逐次聚为一枝,芥蓝、萝卜及甘蓝寄主种群随代次的增多种群分化出现稳定规律性。各寄主种群间遗传距离平均值和范围、多态性条带占总条带数目的比例随代次增多而增大,说明种群分化程度随代次增多而加深。     

利用寄主干扰效应防控小菜蛾田间种群的有效性

【目的】多寄主对植食性昆虫寄主选择行为具干扰效应。为探究在田间相似寄主混作是否能引起小菜蛾Plutella xylostella (L.)在寄主上的选择困难,减少在寄主上的产卵量,从而实现保护寄主植物的目标。【方法】本研究利用小菜蛾喜好性高的两种寄主（菜心Brassica campestris L.和芥菜B. juncea Coss）为试验对象,通过寄主植物单作、混作及不同配比与间隔种植等田间试验设计,研究了多寄主对小菜蛾寄主选择行为的干扰效应。【结果】在2年的田间试验中,两寄主混作处理上的虫量均低于单一寄主种植;2012年田间种群生命表数据显示,两种寄主田间混作处理上的小菜蛾种群趋势指数（I =4.797）低于单一寄主种植,菜心与芥菜单一种植处理上的I值分别为6.549与6.858;当菜心与芥菜这两种小菜蛾喜好性相近寄主同时存在时,对小菜蛾的干扰程度与两寄主的搭配比例有关,随着菜心所占比重的增大,田间虫量呈现先减后增的抛物线变化趋势;但两寄主间距在2 m内时,不同种植间隔对小菜蛾虫量变化无差异(F_3,8=0.204,P>0.05)。【结论】结果表明,在田间多寄主种植中,除了可利用陷阱作物来防控小菜蛾外,在相邻两畦地间以适当比例同时种植两种小菜蛾喜好性相近的寄主,利用两种寄主植物对植食性昆虫的寄主选择行为产生的干扰效应,也能有效影响田间小菜蛾的种群动态。     

十字花科蔬菜对小菜蛾实验种群的影响

通过组建4种十字花科蔬菜上小菜蛾实验种群生命表发现,在菜心、芥蓝、芥菜和小白菜4种蔬菜上繁殖的小菜蛾实验种群增长趋势指数分别为41．0、69．5、38．2、52．4,影响种群增长的重要因子为幼虫的自然死亡,不同蔬菜种类对小菜蛾雌蛾的总产卵量和寿命无影响,但芥蓝繁殖的小菜蛾日平均产卵量显著高于其它几种蔬菜。在芥蓝和小白菜上繁殖的小菜蛾幼虫具有较高的存活概率,是其种群具有较大增长潜力的重要原因。试验结果表明,在4种蔬菜中,芥蓝提供的营养最适宜于小菜蛾种群生长、发育和繁殖,是最佳的寄主,其次为小白菜、菜心,而芥菜尽管被报道为小菜蛾成虫最喜欢产卵的寄主,由于所繁殖的小菜蛾种群在幼虫期有较高的死亡率,是最不适宜于小菜蛾生长发育的寄主。     

取食不同寄主植物小菜蛾对氯虫苯甲酰胺敏感性及体内解毒酶活性的变化

为探明寄主植物影响小菜蛾Plutella xylostella L.抗药性的内在因素,本研究以小菜蛾嗜好性不同的菜心(Brassica parachinensis)、芥菜(B.juncea)、白菜(B.chinensis)和芥蓝(B.alboglabra)4种寄主植物为材料,利用生物测定和解毒酶活力测定的方法,研究了取食不同寄主植物的小菜蛾幼虫对氯虫苯甲酰胺敏感性及体内解毒酶活力变化情况。结果表明,4种寄主植物饲养小菜蛾5代后,其敏感性分别为菜心>芥菜>白菜>芥蓝,且其体内活性酶谷胱甘肽S-转移酶(GSTs)、羧酸酯酶(CarE)比活力差异显著(P<0.05),活性的强弱与其敏感性相一致。以取食芥蓝的小菜蛾体内2种解毒酶活性最强。说明寄主植物能影响小菜蛾药剂敏感性及解毒酶活性。试验结果对小菜蛾的综合防控及抗氯虫苯甲酰胺机理研究具有重要的参考价值。     

高效液相色谱法检测菜蛾绒茧蜂幼虫体内多杀菌素残留

应用高效液相色谱法检测施用于寄主幼虫的多杀菌素可否传递到在其体内发育的寄生蜂幼虫。以对多杀菌素高抗的小菜蛾Plutella xylostella幼虫作为菜蛾绒茧蜂Cotesia plutellae的寄主,待绒茧蜂发育到1龄幼虫时,将浓度为50 mg/L的多杀菌素点滴到寄主幼虫背板上,随后让寄主幼虫取食经50 mg/L多杀菌素处理过的甘蓝叶片,寄主幼虫和其体内的蜂幼虫再发育3天后,将寄主幼虫解剖取出蜂幼虫,用高效液相色谱法对经多杀菌素处理的小菜蛾幼虫体液以及绒茧蜂幼虫匀浆液进行检测,结果多杀菌素的2个活性成分spinosyn A和spinosyn D均被检测到,两者的多杀菌素残留浓度分别是2.79 mg/L和0.94 mg/L。这表明,通过寄主幼虫体壁接触和取食进入其体内的多杀菌素,可通过寄生蜂幼虫体壁浸透、蜂幼虫对寄主血淋巴的取食,或这两种途经一起进入蜂幼虫的体内,对蜂幼虫产生作用。     

土壤和植物对冬虫夏草寄主昆虫规模化饲养的影响

冬虫夏草大量人工培植的关键之一是寄主昆虫的规模化饲养,本文对西藏林芝地区冬虫夏草生境中不同土壤基质在室内对蝙蝠蛾幼虫生长的影响以及寄主幼虫对5种植物的取食行为、嗅觉反应进行了系统研究。结果表明蝙蝠蛾幼虫偏好土质疏松、渗透性好的土壤,土壤因子中湿度和有机质含量与蝙蝠蛾幼虫存活率成正相关。蝙蝠蛾3龄幼虫对适生地植物的取食选择性与嗅觉反应趋性顺序为鹅绒委陵菜>珠芽蓼>小大黄>圆穗蓼>羊角天麻;进一步Spearman相关分析显示,幼虫对各植物的选择系数与可溶性糖（R=0.850,P<0.05）和粗蛋白（R=0.898,P<0.05）都存在显著的正相关关系,而与粗纤维（R=-0.952,P<0.05）有着显著的负相关关系,与粗灰分（R=-0.391,P=0.516）之间没有显著的相关关系;取食鹅绒委陵菜、珠芽蓼后的幼虫单头虫重显著大于取食其他植物的幼虫。这一研究结果为冬虫夏草寄主昆虫规模化饲养提供了理论依据。     

Laboratory evaluations of a wild crucifer Barbarea vulgaris as a management tool for the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae)

The term 'dead-end trap cropping' has recently been proposed to identify a plant that is highly attractive for oviposition by an insect pest, but on which offspring of the pest cannot survive. The potential of the wild crucifer Barbarea vulgaris R. Br. to allure and serve as a dead-end trap crop for the diamondback moth Plutella xylostella (L.), an important pest of cruciferous crops worldwide, was examined in laboratory experiments. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris, and Chinese cabbage Brassica campestris (L.), in one arena, adult moths laid 2.5-6.8 times more eggs on the former than on the latter. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris and common cabbage Brassica oleracea L., adult moths laid virtually all their eggs on the former and ignored the latter. Nearly all P. xylostella eggs laid on the three species of plants hatched successfully, but nearly all individuals on plants of B. vulgaris died as neonates or early instar larvae, while 87-100% of the larvae on Chinese cabbage and common cabbage survived to pupation. Dual choice tests with a Y-tube olfactometer showed that volatiles from B. vulgaris were much more attractive to P. xylostella adults than those from common cabbage. The results demonstrate that B. vulgaris has a great potential as a dead-end trap crop for improving management of P. xylostella. Factors that may influence the feasibility of using B. vulgaris as a trap crop in the field are discussed, and ways to utilize this plant are proposed.     

Differential parasitism of Plutella xylostella (Lepidoptera: Plutellidae) larvae by the parasitoid Cotesia plutellae (Hymenoptera: Braconidae) on two host plant species

Laboratory experiments were conducted to examine host selection by Cotesia plutellae Kurdjumov when larvae of its host, Plutella xylostella (Linnaeus), fed on Chinese cabbage, Brassica campestris L. ssp. pekinensis and those fed on common cabbage, Brassica oleracea L. var. capitata were provided simultaneously, and to investigate the roles of plant and host volatiles in mediating host selection. When C. plutellae were provided with equal numbers of host larvae on plants of the two species in one arena, the parasitoid parasitized 4- to 15-fold more host larvae on Chinese cabbage than on common cabbage. This preference changed little with host density. However, an experience of searching coupled with an oviposition in a host larva on a leaf of the less-preferred plant, common cabbage, significantly increased the preference for parasitizing host larvae on this plant and resulted in twice as many host larvae parasitized on this plant than on Chinese cabbage. Dual choice tests with a Y-tube olfactometer showed that plant volatiles from Chinese cabbage were more attractive to female C. plutellae than those from common cabbage when plants of both species were either intact or infested. In parallel to the increased parasitism on common cabbage following experience, oviposition in a host larva on this less-preferred plant significantly increased the response to volatiles emanating from that plant. These results indicate that host plants may strongly influence the foraging behaviour of C. plutellae, but their differential attractiveness to the parasitoid may be altered by experience of the parasitoid.     

叶类蔬菜的硝态氮累积及成因研究

在菜园土壤上进行的田间试验,用禾谷类作物冬小麦作比较,研究了菠菜、小白菜、大青菜和油菜等叶类蔬菜累积硝态氮的特点,结果表明：硝态氮累积是一般早作作物的共性,苗期更为明显,无论蔬菜还是冬小麦均有较高的硝态氮含量（367.8-1413.4μg/g);但随生育期后延,蔬菜的硝态氮含量波动升高,冬小麦波动降低,盆栽试验表明,施入土壤的氮肥是蔬菜硝态氮累积的主要来源,过量施用氮肥所导致的蔬菜硝态氮吸收与还原转化不平衡是产生累积的根本原因,吸收与生长不协调更使累积过程加剧。     

Preimaginal conditioning does not affect oviposition preference in the diamondback moth

Abstract.  1. In holometabolous insects, learning has been demonstrated in both larval and adult stages. Whether learning can be retained through metamorphosis from larva via pupa to adult has long been a subject of debate. The present study is designed to distinguish between preimaginal and imaginal conditioning in the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) using oviposition preference tests on females exposed to various types of learning experiences during immature and adult stages.
2. Cohorts of test insects were reared from egg to pupa on an artificial diet, or on one of two host plants, Chinese cabbage, Brassica campestris L. ssp. pekinensis , and common cabbage, Brassica oleracea L. var. capitata . The ensuing females reared on the three kinds of food showed similar oviposition preference between the two plants. A brief experience of the less preferred host, common cabbage, by adults slightly increased their preference for this plant.
3. Cohorts of test insects were reared from egg to pupa on an artificial diet with or without the addition of a neem-based oviposition deterrent (Neemix^® 4.5). Larval feeding experience did not alter oviposition response to the deterrent. However, emergence conditioning and early adult learning, achieved through experience of a residue of the deterrent carried over from the larval food on pupal cuticle and cocoons, altered oviposition preference significantly.
4. The combined results revealed no evidence of preimaginal conditioning in this insect but a strong effect of emergence conditioning and early adult learning on oviposition preference.     

Growth and Major Nutrient Concentrations in Brassica campestris Supplied with Different NH4+/NO3- Ratios

In the present study, we investigated whether growth and main nutrient ion concentrations of cabbage (Brassica campestris L.) could be increased when plants were subjected to different NH4+/NO3- ratios. Cabbage seedlings The results showed that cabbage growth was reduced by 87% when the proportion of NH4+-N in the nutrient solution was more than 75% compared with a ratio NH4+/NO3- of 0.5:0.5 35 d after transplanting, suggesting a possible toxicity seedling weight, root length, and H2PO4- (P), K+, Ca2+, and Mg2+ concentrations were all higher than those in plants 0.5 NH4+/NO3-. The present results indicate that an appropriate NH4+/NO3- ratio improves the absorption of other nutrients and maintains a suitable proportion of N assimilation and storage that should benefit plant growth and the quality of cabbage as a vegetable.     

白菜类蔬菜资源的农艺性状分析及应用研究

通过对505份白菜类蔬菜：大白菜、小白菜和紫菜薹的田间观察鉴定,同时抽取其中有代表性的材料90份(每类型30份)以白菜型油菜(30份)为对照进行农艺性状考察,结果显示：白菜类蔬菜种质资源中存在有符合油莱育种目标的特异性状,如特早熟型、白花、黄籽、抗寒型、矮杆、多分枝、多角果、大粒、特殊不育类型等。从变异幅度看,白菜类蔬菜资源的大多数农艺性状的变异系数大于白菜型油菜。同时通过核心种质资源构建,从120份材料中筛选出40份(每类10份)进行系统聚类分析,结果将40份供试材料共分为12类,其中紫菜薹和白菜型油莱各聚为一类,而小白菜和大白菜的聚类结果比较复杂,类型较多,这说明白菜类蔬菜资源与普通白菜型油菜的亲缘关系较远,遗传背景差异较大,用它们测配杂交组合优势明显,这一点在实际应用中已被证实。同时通过对白菜类蔬菜不育系和甘蓝型油菜不育系接受外界花粉能力的比较得到,白菜类蔬菜不育系的异交率极高。这一特性为其杂交优势利用提供了科学依据。     

Diamondback moth oviposition: effects of host plant and herbivory

The oviposition behaviour of Plutella xylostella L. (Lepidoptera: Plutellidae) on Chinese cabbage (Brassica rapa L. Pekinensis, cv. Wombok), canola (Brassica napus L. cv. Thunder TT), and cabbage (Brassica oleracea L. Capitata, cv. sugarloaf) (Brassicaceae) was studied in the laboratory. In no‐choice experiments moths laid most eggs on the stems and lower three leaves of cabbage plants, the lower three leaves of canola plants, but on the upper three leaves of Chinese cabbage plants. The effects of conspecific herbivore damage to foliage could be replicated by mechanical damage. When foliage was damaged, injured cabbage and canola plants were preferred for oviposition over intact conspecifics, whereas injured Chinese cabbage plants were less preferred than intact conspecifics. However, when root tissue was damaged, intact cabbage and canola plants were preferred over injured conspecifics, whereas moths did not discriminate between root‐damaged and intact Chinese cabbage plants. Injury to upper leaves significantly affected the intra‐plant distribution of eggs. In cabbage and canola plants, injury to leaf 6 significantly increased the number of eggs laid on this leaf, resulting in a significant decrease in the number of eggs laid on the lower foliage/stem of plants, whereas in Chinese cabbage plants it significantly decreased the number of eggs laid on leaf 6. Following oviposition on intact plants, neonate larvae established the vast majority of feeding sites on leaves 5–8 in all three host plants, indicating that larvae moved a considerable distance from preferred oviposition sites in cabbage and canola plants. The growth rate of neonates fed on leaf‐6 tissue was significantly greater than that of those fed on leaf‐1 tissue; >90% of larvae completed development when fed exclusively on leaf‐6 tissue but no larvae completed development when fed exclusively on leaf‐1 tissue. The study demonstrates the complex and unpredictable interactions between P. xylostella and its host plants and provides a basis from which we can begin to understand observed distributions of the pest in Brassica crops.     

Evaluating trap crops for diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

Potential trap crops for the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), were evaluated through a series of ovipositional preference and larval survival experiments in outdoor screenhouses in 2002 and 2003. Hosts examined as trap crops were glossy and waxy collards, Brassica oleracea L. variety acephala; Indian mustard, Brassica juncea (L.) Czern; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata. More eggs were laid on the potential trap crops, with the exception of waxy collards, than on cabbage. When P. xylostella was offered multiple hosts at the same time, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 3, 18, and 12 times greater than on cabbage, respectively. Similarly, when P. xylostella was offered a single trap crop host and cabbage, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 300, 19, and 110 times greater than on cabbage, respectively. Our studies suggest differences in oviposition between the potential trap crops and cabbage were likely due to host volatiles, leaf morphology and color, or a combination of these factors, rather than to total leaf areas, leaf shape, or plant architecture. Two-choice tests with a Y-tube olfactometer indicated that plant volatiles were major factors in P. xylostella host preference. The percentage larval survival from egg to pupation was 22.2% on cabbage, 18.9% on waxy collards, and 24.4% on Indian mustard, whereas survival was significantly lower on glossy collards (6.7%) and yellow rocket (0%). Based on our tests, it seems that yellow rocket may be the best candidate for use as a trap crop for P. xylostella because it is highly attractive for oviposition, but larvae do not survive on it.     

Manipulating the attractiveness and suitability of hosts for diamondback moth (Lepidoptera: Plutellidae)

Ovipositional preference and larval survival of the diamondback moth, Plutella xylostella (L.), were compared among cabbage, Brassica oleracea L. variety capitata; glossy collards, Brassica oleracea L. variety acephala; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata in different treatments of planting density, host plant age, intercropping, and water stress in 2003 and 2004. P. xylostella laid nearly twice as many eggs per plant in the high planting densities of glossy collards and yellow rocket than in the standard planting densities. Ovipositional preference was positively correlated with plant age in cabbage, glossy collards, and yellow rocket. Larval survival on cabbage was 1.9 times higher on 6-wk than on 12-wk-old plants, whereas larval survival on collards was 12.1 times higher on the younger plants. No larvae survived on either 6- or 12-wk-old yellow rocket plants. Intercropping cabbage with either tomato, Lycopersicon esculentum Mill., or fava bean, Vicia fava L., did not reduce the number of eggs laid on cabbage. No significant differences in oviposition were found between water-stressed and well-irrigated host plants treatments. Yet, P. xylostella larval survival on water-stressed cabbage was 2.1 times lower than on well-irrigated cabbage plants. Based on our findings, the effectiveness of trap crops of glossy collards and yellow rocket could be enhanced by integrating the use of higher planting densities in the trap crop than in the main crop and seeding of the trap crop earlier than the main crop.