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Miss Chen
2018年05月29日
Miss Chen
很多人养花往往是处于一时爱好，并没有根本的养花常识，所以常常面对的是自个的盆栽植物萎蔫等现象束手无策，或是盲目的进行处理，导致植物走向死亡。 植物出现萎蔫现象，这也是最使养花者头痛的问题，造成植物萎蔫的原因很多，如缺水、缺肥、缺少光照、温度不适应，对土壤中所含酸碱度不适应、施化肥过量、感染了病毒、遭到了虫害受到空气有毒气体的损害等等，情况十分复杂，不过，大多数是由于水分不够造成的。
（1）由于空气过于干燥而造成的萎蔫，弥补的办法是对植物周围的地面，叶面每天喷水2?3次； （2）由于盆土缺水，常常是由于养花者每次浇水的量太少，只把锱土表面浇潮了就以为够了，结果是花卉的根部吸收不到水分，这是花卉的浇水的大忌，养花者称之为“浇半截水”，这样时间长了，花卉自然要因为得不着水分而萎蔫。 （3）补救的办法，当然是对盆土进行浇水，但这里有一个特别值得注意的问题：这时对盆土浇水只能逐渐增加浇水量，不可猛然一下子浇得太多，这是因为当花卉植株萎蔫时，它的根毛已经萎缩，丧失了吸水的功能，同时，萎蔫已使细胞失水，若供应水分骤然过多，会使细胞壁和原生质发生质壁分离，所以植物在干旱之后，猛然吸入大量的水分时，也会导致死亡。
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Miss Chen
2018年05月29日
Miss Chen
康乃馨是优异的切花品种。矮生品种还可用于盆栽观赏。花朵还可提香精。这种体态玲珑、斑谰雅洁、端庄大方、芳香清幽的鲜花，随着母亲节的兴起，成为全球销量最大的花卉。 我国广泛栽培供观赏，有很多园艺品种，耐瓶插，常用作切花，温室培养可四季开花。
康乃馨的常见病害有叶斑病、灰霉病等；主要虫害是蚜虫、红蜘蛛 康乃馨叶斑病。 又名茎腐病，是康乃馨的一种严重病害。多发生在叶和茎上，有时也发生在蕾和花上。在叶片上发病多从下部开始，先产生淡绿色水渍状小圆斑，后逐渐变为紫色。随着病斑的扩大，病斑中央发生枯死。边缘褐色，病斑有圆形、椭圆形或不规则形，直径约4-5毫米，中央枯死部分为灰白色至灰色，以后在病斑上产生黑色霉层。植株受害严重时，叶片枯萎下垂，但不脱落，在枝条上，病斑绕茎或分枝一周后，上部枝叶和花蕾即萎缩枯死。 此病从4月上旬到初冬均可发生，在温室中栽培全年皆可发病，盛夏雨季发病最为严重。如果栽植过密，则蔓延很快。但此病在北方却发病较少。 防治方法：①在南方发病严重的地区栽种，应从健壮的植株上选择无病枝条，以防止病菌初次侵染；也可以引一生中北方抗菌力强的细叶品种栽种。②摘芽、切花后，可选用75%百菌清、70%代森锰锌或80%代森锌可湿性粉剂500倍溶剂化喷洒，也可以喷施1%的波尔多液防治，效果都很好。如生长期发病，应及时摘除病叶或拔除病株，并喷洒上述药剂，防止病情蔓延。 康乃馨灰霉病。 此病多发生在花瓣和花蕾上，偶有发生在茎叶。花瓣感病后，起初花瓣的边缘出现淡褐色水浸状，逐渐大部分花瓣被灰色真菌侵入繁衍，此时如果气温较高，湿度较大，就易造成腐烂。花蕾上发病时，呈水浸状不规则斑，并逐渐发生腐烂，使整个花蕾不能开放。 防治方法：①注意室内通风透光，降低湿度；②发现病株及时清除；每隔15天左右喷一次75%的百菌清可湿粉剂500倍液，连喷2-3次，有效好的防治效果。 康乃馨如发生锈病，可喷洒敌锈钠800倍液。 康乃馨遭蚜虫、红蜘蛛等危害时，可喷40%乐果乳剂1000倍液或80%敌敌畏乳剂1000倍液防治。
养护注意事项 1、光照条件。康乃馨属中日照植物，喜阳光充足。除育苗期和盛花期外， 无须担心强光为害，且借助辅助光可增加花冠直径和花色鲜艳度。光强与单位面积切花产量有明显的正相关性。 2、温度条件。康乃馨喜凉爽，不耐炎热，可忍受一定程度的低温。若夏季气温高于35℃，冬季低于9℃，生长均十分缓慢甚至停止。在夏季高温时期，应采取相应降温措施，冬季则需盖塑料薄膜或进入温室，以保持适当的温度。 3、水分条件。康乃馨根系为须根系，土壤或介质长期积水或湿度过高、叶片表面长期高温，均不利于其正常生长发育。因此提倡滴灌，另外还应注意水质及水分含盐量的问题。 4、土壤条件。康乃馨喜保肥、通气和排水性能良好的土壤，其中以重壤土为好。适宜其生长的土壤pH值是5.6~6.4。从一些土壤分析实验表明，pH值在5.95~7.9范围内，土壤有机质含量对开花无明显影响，主要决定于土壤质地。
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Miss Chen
2018年05月29日
Miss Chen
害虫对杀虫剂抗性发展的历史，也就是杀虫剂发展应用的历史。随着有机合成杀虫剂的出现和推广应用，害虫抗药性发展速度明显加快，由于有机氯和有机磷杀虫剂的大量使用，抗性害虫的种树几乎成直线上升。
害虫抗药性的特点是害虫几乎对所有合成化学农药都会产生抗药性；害虫抗药性是全球现象，抗性形成有地区性，主要取决于该地用药历史与用药水平。双翅目、鳞翅目昆虫产生抗药性种树做多，农业害虫抗药性虫种树超过卫生害虫，重要农业害虫如蚜虫、棉铃虫、小菜蛾、菜青虫、马铃薯甲虫及螨类的抗药性尤为严重。世界卫生组织对害虫的抗药性下的定义是“昆虫具有忍受杀死正常种群大多数个体的药量的能力在其种群中发展起来的现象”。昆虫抗药性是指种群的特性，而不是昆虫个体改变的结果；抗性是相对于敏感种群而言；抗性有地区性，即抗性的形成与该地的用药历史、药剂的选择压力等有关；抗性是由基因控制的，是可遗传的，杀虫剂起了选择压力的作用。
第一、轮换用药 不要长期单一使用某种农药防治某种害虫，这样就可以切断害虫抗药性种群的形成过程。轮换使用的品种应尽可能选用作用机制不同的农药。如有机磷农药、拟除虫菊酯类农药、氨基甲酸酯类农药、生物制剂类农药等，杀虫原理各不相同，可交替使用。同一类的农药品种轮换使用应慎重，因害虫易获得交互抗性，即对某种农药产生抗性后，对和该种农药同类的其他品种也会产生抗性。 第二、混合用药 两种作用方式和机制不同的农药混合使用，可减缓害虫抗药性的发生速度，即使抗药性已经形成，混合用药也能对抗药性起抑制作用。以前，混合用药较成功的方案有：敌百虫、敌敌畏与马拉硫磷混用；菊酯类杀虫剂与有机磷类杀虫剂混用；敌百虫与辛硫磷混合使用；机油乳剂与有机磷杀虫剂混用等。 必须注意的是，混配农药也不能长期单一使用，要轮换用药，否则，同样有引起抗药性的危险，甚至引发害虫产生多种抗药性。 第三、农药的间断使用或停用 当一种农药已经引发了某种害虫的抗药性以后，如在一段时间内停止使用该农药，则害虫的抗药性会逐渐减退甚至消失。如某些有机磷农药引起红蜘蛛的抗药性，经过若干年停用后，红蜘蛛的抗药性可基本消失。这样，药剂的作用仍可恢复。 第四、添加增效剂 在农药中加入增效剂，可明显起到活化农药、提高药效、延缓和抑制害虫产生抗药性的作用。如在氧化乐果中加入少量柴油防治蚧壳虫，可溶蚀蚧壳，使农药进入害虫体内，克服了蚧壳虫对氧化乐果的抗药性。除油类物质外，常用的增效剂还有中性洗衣粉、豆浆、植物油等。 第五、多样化的施药方法 农药的使用方法除了常规的喷雾外，还可采用其他方法，如拌毒土、制毒饵、土壤施药、涂药、滴药、烟熏等，不同的用药方法交替进行，有助于预防和克服害虫产生抗药性。 第六、开发使用土农药 土农药原料来源广，制作简单，对害虫不会诱发抗药性。目前，有待开发的土农药主要是植物性农药，如烟草、蓖麻、大蒜、辣椒水、韭菜等。此外洗衣粉、油类、生石灰、烧碱、松香等，这些都是配置土农药的好原料。
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文章
Miss Chen
2018年05月29日
Miss Chen
蛀心虫，又称食心虫。蛀心虫的种类很多，包括天牛幼虫、粉蛾幼虫和其他昆虫的幼虫等，一般钻入枝梢内啃食木质进行为害，受其影响的果树，轻者生长不良、树势衰弱黄化，重者甚至整棵树死亡。 蛀心虫种类很多，有天牛幼虫、粉蛾幼虫和其他昆虫的幼虫等。蛀心虫最初蛀入嫩枝，然后再向枝干部蛀入。樱花、梅花、无花果、蔷薇等最易受害。现总结出防治蛀心虫的方法如下：
一、用铁丝伸入蛀孔，刺死蛀虫。也可把铁丝的尖端回弯成钩形，将虫体钩出。 二、在蛀孔中塞入一团浸透了敌敌畏溶液的棉花球，把蛀孔口用黏土或凡士林等封闭，则蛀虫可被杀死。 三、在蛀孔内注射纯酒精，使之渗入枝干，将虫杀死。 四、蛀心虫的卵一般产在幼茎上，孵化后的幼虫沿着幼茎爬动，可及早撒布驱虫的药剂。 五、已有蛀心虫蛀入的枝干，可从蛀孔下70厘米左右连同虫体一起剪去。
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Miss Chen
2018年05月28日
Miss Chen
Description: This perennial wildflower is 2-6' tall and usually unbranched, except toward the apex where the flowerheads occur. The glabrous central stem is light green to purple. The alternate leaves are up to 8" long and 6" across (excluding the petioles), becoming gradually smaller as they ascend the central stem. They are quite variable in shape; the lower leaves are often divided palmately into 3 lobes (or less often 5 lobes), while the upper leaves often lack lobes (ovate or deltoid). The margins of the leaves are undulate, dentate, or entire (smooth). The upper surface of each leaf is medium to dark green and hairless, becoming yellowish green with age. The petioles are as long as the leaf blades or somewhat shorter. The foliage of this plant contains a white latex. The central stem terminates in a panicle of flowerheads that is about as wide as it is tall; smaller panicles often develop from the axils of the upper leaves. The typical panicle will have 2-4 widely spreading branches at the apex of a central stalk (peduncle); from each of these branches, several flowerheads and their buds hang downward from shorter branches (pedicels). These branches are hairless or slightly pubescent and light green to pale purple. Each flowerhead is up to ¾" long and ½" across when it is fully open; it has 5-6 outer ray florets and no disk florets. The ray florets are greenish white, cream-colored, or greenish yellow. The cylindrical base of each flowerhead has about 5 primary bracts (phyllaries) that are light green and hairless; each of these bracts is linear in shape and about ½" in length. At the very bottom of each flowerhead, there are also several secondary bracts that are much shorter than the primary bracts. The blooming period occurs from late summer into the fall and lasts about a month. Each ray floret is replaced by an achene with a small tuft of hair; these hairs are either light tan (var. altissima) or orange-brown (var. cinnamomea). The achenes are distributed by the wind. The root system is tuberous. Sometimes this species forms small colonies of plants.
Cultivation: Preferred growing conditions consist of light shade to dappled sunlight and fertile loamy soil that is moist to slightly dry. Rocky or sandy soil is also tolerated. The size of individual plants can be highly variable depending on soil fertility, moisture conditions, and light levels. Range & Habitat: The native Tall White Lettuce is occasional in southern and extreme eastern Illinois, otherwise it is rare or absent (see Distribution Map). This species is more common further to the east. Habitats include rich mesic woodlands, rocky upland woodlands, sandy woodlands, bluffs and shaded ravines, woodland borders, swamps and seeps, and shaded to partially shaded riverbanks. This species is found in deciduous woodlands where Sugar Maple, American Basswood, and/or American Beech are often present as canopy trees. Faunal Associations: Information about floral-faunal relationships for this species is limited. Bumblebees suck nectar from the flowerheads and cross-pollinate them; Halictid bees, beetles, and other insects may feed on the pollen, but they are not effective pollinators. Even though it has a bitter taste, White-Tailed Deer occasionally browse on the foliage.
Photographic Location: A deciduous woodland at Turkey Run State Park in west-central Indiana. Comments: Two major groups of woodland lettuce can be found in Illinois and neighboring states: species of Wild Lettuce (Lactuca spp.) and species of White Lettuce (Prenanthes spp.). Species in the former group have flowerheads that are erect or hang sideways, while species in the latter group have flowerheads that droop downward. Tall White Lettuce can be easily distinguished from other species of White Lettuce in Illinois by examining the primary bracts (or phyllaries) of the flowerheads: each flowerhead has 5 primary bracts (phyllaries) that are light green and hairless (less often there are 4 or 6 bracts). Other species of White Lettuce in Illinois have 8 or more primary bracts; depending on the species, these bracts may be hairy or pale purple. As a general rule, leaf shape is unreliable as a guide to identification because it is highly variable within each species of White Lettuce. Other common names that are sometimes applied to Prenanthes altissima and similar species include Lion's Foot and Rattlesnake Root.
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Miss Chen
2018年05月28日
Miss Chen
Description: This herbaceous perennial wildflower is 2-5' tall; it has an erect central stem and often develops short side stems in the upper half. The central stem is terete, light green to purple (usually the latter), glabrous, and glaucous. The alternate leaves are up to 8" long and 6" across (excluding the petioles), becoming gradually smaller as they ascend the stems. The leaves are variable in shape; they are usually 3-5 lobed and less often deltate or ovate. The margins of these leaves are dentate, undulate, or smooth. The upper surface of each leaf is medium to dark green and glabrous. The winged petioles are as long as their leaf blades or shorter. Both the stems and leaves contain a milky white latex. The central stem and upper stems (if any) terminate in panicles of flowerheads up to 2' long and 1' across. Each panicle has a central stalk that divides at its apex into 2-4 spreading branches; there may be some lower branches below. From each branch, several flowerheads droop downward from very short branchlets and peduncles. The light green to purple branches, branchlets, and peduncles of each panicle are glabrous. Each flowerhead is about ¾" long and ½" across. The cylindrical base of each flowerhead has 8 primary bracts (phyllaries) that are linear in shape, pale greenish purple to purple, and glabrous. There are also several secondary bracts at the very bottom of the flowerhead that are much shorter than the primary bracts. The upper flowerhead has 8-14 outer ray florets and no disk florets; the petaloid rays of these florets spread outward widely when the flowerhead is in bloom. These petaloid rays are pale purple, lavender, or white; they are linear in shape with minutely toothed truncate tips. The blooming period occurs from late summer into the fall. A pleasant floral fragrance is sometimes present. The florets are replaced by small oblongoid achenes with tufts of cinnamon-brown hair at their apices; the achenes are distributed by the wind. The root system is fleshy. Cultivation: Preferred growing conditions consist of light shade to dappled sunlight, average levels of moisture, and a fertile loamy soil. Soil that is sandy or rocky is also tolerated. The size of individual plants is strongly influenced by moisture amounts, light levels, and soil fertility.
Range & Habitat: The native White Lettuce is occasional in the northern half of Illinois, but it is rare or absent elsewhere within the state (see Distribution Map). This species is more common in areas that lie north and east of the state. Habitats include rich mesic woodlands, sandy woodlands, stabilized sand dunes with scattered trees, bluffs, wooded slopes, rocky ravines and cliff bases in wooded areas, and woodland borders. White Lettuce can be found in oak, maple-basswood, and other deciduous woodlands. Faunal Associations: The flowerheads are cross-pollinated by bumblebees, which seek nectar. The following aphids have been observed on White Lettuce: Hyperomyzus nabali, Uroleucon ambrosiae, and Uroleucon chrysanthemi. Even though the foliage of this species has a bitter taste, it is sometimes browsed by White-Tailed Deer. Photographic Location: A stabilized sand dune at Indiana Dunes State Park near Lake Michigan.
Comments: White Lettuce is one of five Prenanthes spp. in Illinois; two of these species occur in prairies, while the other three species occur in woodlands. The prairie species in this genus have narrow spikes of flowerheads and lanceolate leaves. The woodland species in this genus have spreading panicles of flowerheads and their leaves are often lobed (particularly the lower ones). White Lettuce can be distinguished from the other woodland species in Illinois by its primary bracts (phyllaries): Each flowerhead has 8 primary bracts that are pale purple-green and hairless. In contrast, each flowerhead of Prenanthes altissima (Tall White Lettuce) has 5 primary bracts that are light green and hairless, while the flowerhead of Prenanthes crepidinea (Great White Lettuce) has 12-15 primary bracts that are light green and hairy. These species also differ in the number of outer ray florets per flowerhead. Other common names of Prenanthes alba are Lion's Foot and Rattlesnake Root.
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Miss Chen
2018年05月28日
Miss Chen
Description: This herbaceous plant is about 1½–4½' tall, branching occasionally. It is a biennial or short-lived perennial. The erect to ascending stems are light green to dull reddish brown, terete, and densely covered with long hairs. The alternate or opposite leaves are up to 12" long and 8" across, becoming gradually smaller as they ascend the stems. They have pubescent petioles up to 4" long that are grooved above and convex below. The lower to middle leaves are pinnately lobed and somewhat dentate or undulate along their margins; they usually have 5-7 major lobes with pointed tips. The upper leaves have pairs of basal lobes or they lack lobes; they are ovate, broadly hastate, or sometimes another shape. The upper leaf surface is dull medium green; it is usually hairless for older leaves and appressed-hairy for younger leaves. The lower leaf surface is pale green and pubescent primarily along the major veins. At the bases of petioles, there are pairs of large green stipules. These stipules are connate (merged together) and their margins are coarsely dentate. Small cymes of several flowerheads develop from the upper stems and the axils of upper leaves. The branches of these cymes are green and pubescent. Sometimes there are 1-2 small linear bracts where the branches diverge, and sometimes they are found underneath the flowerheads. These bracts are green, pubescent, and about 8 mm. (1/3") in length. Each flowerhead is about ½" across, consisting of several disk florets in the center and 5-8 ray florets around its circumference.
The small disk florets have cream-colored tubular corollas with 5 lobes; they are staminate. The petaloid rays of the flowerheads are white, obovate, short, and 3-lobed; sometimes they are absent. Only the ray florets produce achenes. Surrounding the base of each flowerhead, there are 5 floral bracts (phyllaries) that are light green, pubescent, and lanceolate in shape; they become recurved when the flowerheads bloom. The blooming period occurs from mid-summer into the fall, lasting about 2 months. Only a few flowerheads are in bloom at the same time. Somewhat later, the flowerheads turn brown and their ray florets are replaced by obovoid achenes that are 3-angled, dark brown, and 3-4 mm. in length. These achenes lack tufts of hair. The root system is fibrous, although a poorly developed taproot is sometimes present.
Cultivation: This species is typically found in light to medium shade, moist to slightly dry conditions, and loamy to slightly rocky soil with abundant organic matter. The size of individual plants is variable, depending on moisture conditions and soil fertility. In the flower garden, this species may be short-lived. Range & Habitat: Leaf-Cup (Polymnia canadensis) is uncommon to occasional throughout Illinois (see Distribution Map), where it is native. Habitats include rich deciduous woodlands, upland rocky woodlands, bases of bluffs, shaded moist ravines, wooded slopes, shaded areas along streams, and edges of limestone or sandstone glades. This wildflower is associated with oak-hickory, maple-linden, and maple-beech woodlands; it is usually found in higher quality woodlands where the original ground flora is still intact.
Faunal Associations: The nectar and pollen of the flowerheads attract honeybees, bumblebees, and miscellaneous flies (Sharp, 2002). Small bees probably visit the flowerheads in some areas as well. Ants feed on nectar from the disk florets of the flowerheads, but they are ineffective at cross-pollination (personal observation). Other insects suck plant juices or feed on the leaves of Leaf-Cup (Polymnia canadensis). These species include several plant bugs (Macrolophus spp., Dicyphus gracilentus, Plagiognathus albifascies), the aphids Uroleucon zinzalae and Capitophorus hippophaes, and the leaf beetle Sumitrosis inaequalis. The larvae of this latter species are leaf-miners. Several species in the Orthoptera feed destructively on the flowerheads (Gangwere, 1961); they include Neoxabea bipunctata (Two-spotted Tree Cricket), Oecanthus niveus (Narrow-winged Tree Cricket), Scudderia furcata (Fork-tailed Bush Katydid), and Anaxipha exigua (Say's Trig). The relationships of Leaf-Cup to vertebrate animals is currently unavailable.
Photographic Location: A deciduous woodland at the Portland Arch Conservation Area in west-central Indiana. Comments: This woodland wildflower is a medium-large leafy plant. However, Leaf-Cup isn't very well known among members of the public because its small flowerheads are not very showy. These flowerheads are somewhat similar in appearance to those of a weedy introduced plant, Galinsoga quadriradiata (Peruvian Daisy). However, this latter species is a much smaller plant of open areas. The closest relative of Leaf-Cup is Smallanthus uvedalius (Bear's Foot), which has larger yellow flowerheads and palmately lobed leaves. This latter species can become up to 8' tall. In Illinois, it is restricted to the southern part of the state.
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Miss Chen
2018年05月28日
Miss Chen
Description: This herbaceous plant is 1-2½' tall with an ascending leafy stem that is unbranched. The central stem is light to medium green, slightly zigzag, and glabrous to short-pubescent. Alternate leaves occur along this stem that are 2-5" long and 1-2½" long; they are broadly elliptic in shape, smooth (entire) along their margins, and sessile. The upper leaf surface is medium to dark green and glabrous, while the lower leaf surface is pale to medium green and finely short-hairy along the major veins (a 10x hand lens may be required to see this). Leaf venation is parallel with 3-7 prominent veins. Flowers are produced individually or in groups of 2-3 from the axils of most leaves; they are suspended below the leaves on short peduncles and pedicels. Each flower is 8-14 mm. in length and narrowly cylindrical in shape, consisting of 6 pale greenish yellow to greenish white tepals, 6 inserted stamens, and a 3-celled ovary with a single style. Around the outer rim of each flower, there are 6 straight to slightly recurved lobes about 2-3 mm. in length. The filaments of the stamens are minutely warty and terete. The peduncles and pedicels are light green, slender, and glabrous; they are about ¼-½" in length during the blooming period, but become about ½-1" in length when berries are produced. The blooming period occurs from mid- to late spring, lasting about 3 weeks. During the summer, the flowers are replaced by berries. At maturity, these berries are dark blue-violet to black, globoid in shape, and often glaucous; they are 6-9 mm. across. The interior of these berries is fleshy with several seeds. Individual seeds are 1.5-3.0 mm. long, globoid in shape, and either tan or straw-colored. The root system has knotty rhizomes up to ½" thick. Small clonal colonies are often produced from these rhizomes. Cultivation: The preference is partial sun to medium shade, moist conditions, and soil containing either loam or sandy loam with decaying organic matter. Most growth and development occurs during the cool weather of spring.
Range & Habitat: The native Hairy Solomon's Seal is rare in northern Illinois, while in the rest of the state it is absent (Distribution Map). It is state-listed as 'endangered.' Illinois lies along the southern range limit of this species (excluding mountainous areas in the Appalachians). Habitats include moist to mesic woodlands, sandy woodlands, and lower slopes of forested sand dunes near Lake Michigan. In Illinois, Hairy Solomon's Seal is found in higher quality natural areas. Faunal Associations: The flowers attract the Ruby-throated Hummingbird, honeybees, bumblebees, and probably other bees. These floral visitors feed primarily on the nectar, although some of the bees also collect pollen for their larvae. A small number of insects feed destructively on the foliage and plant juices of Polygonatum spp. (Solomon's Seal species). These insects include the aphids Catamergus kickapoo and Macrosiphum gei, the thrips Ctenothrips bridwelli, and caterpillars of the moth Clepsis melaleucana (Black-Patched Clepsis). The berries are probably eaten by such woodland birds as the Ruffed Grouse, various thrushes, and the Veery. These birds spread the seeds to new areas. White-tailed Deer occasionally graze on the foliage of Solomon's Seal species.
Photographic Location: A moist sandy woodland at the Indiana Dunes State Park in NW Indiana. Comments: This species can be easily confused with the more common Polygonatum commutatum (Smooth Solomon's Seal). Hairy Solomon's Seal tends to be a smaller plant that produces fewer flowers and berries underneath its leaves (usually only 1-2 flowers or berries per leaf). It also has a tendency to bloom a little earlier in the year than the latter plant. However, the most distinctive characteristics of Hairy Solomon's Seal are 1) the short fine hairs along the veins of its leaf undersides, and 2) the warty filaments of its flowers.
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Miss Chen
2018年05月28日
Miss Chen
Description: This herbaceous perennial plant is about 2-3½' tall and unbranched. The central stem is glabrous, glaucous, and terete (circular) in circumference; it leans over to one side. The alternate leaves are up to 6" long and 3½" across; they are spaced fairly close together along the stem. These leaves are pale green, elliptic to ovate in shape, smooth (entire) along their margins, and glabrous; they have parallel veins and clasp the stem. From the axils of the middle and upper leaves, there are nodding umbels of 2-5 flowers (rarely more than this). A typical plant will have 12-20 of these umbels, which hang below the leaves. The peduncles (about 1¼" in length) and pedicels (about ½" in length) of the umbels are slender, green, and glabrous. The flowers are about ½-¾" (13-18 mm.) in length. Each flower has a narrow tubular corolla that is whitish green or pale yellowish green. Along the outer rim of this corolla, there are 6 small lobes that are slightly recurved. Within the interior of the corolla, there is a pistil with a single style and 6 stamens. The blooming period occurs from late spring to early summer, lasting about 3 weeks. Each flower is replaced by a globoid berry that is about 8-10 mm. across at maturity. The berries are initially green, but they eventually become dark blue-violet. The root system produces rhizomes that are rather stout and knobby; on the upper surface of these rhizomes, there are circular scars. This plant often forms clonal colonies. Cultivation: This plant prefers light shade to partial sun, mesic levels of moisture, and fertile loamy soil. It is fairly rugged and tolerates less than ideal conditions. The foliage persists all summer and it is rarely bothered by disease. Range & Habitat: The native Solomon's Seal is a common plant that occurs in every county of Illinois (see Distribution Map). Habitats include moist to slightly dry deciduous woodlands, lower wooded slopes, edges of shady seeps, young flatwoods, woodland borders, and fence rows that are overgrown with shrubs or trees. Less often, Solomon's Seal may occur in meadows near woodlands and open prairies, especially cemetery prairies. Solomon's Seal occurs in both high quality and degraded woodlands.
Faunal Associations: The nectar and pollen of the flowers attract various bees, including bumblebees, Anthophorid bees (Anthophora spp.), and Halictid bees (Lasioglossum spp.). The Ruby-Throated Hummingbird also feeds on nectar from the flowers. Other insects feed destructively on the foliage and other parts of Solomon's Seal. These species include the aphid, Catamergus kickapoo, which sucks sap from the leaf undersides; adults of a thrips, Ctenothrips bridwelli, which are found on the foliage; leaf-rolling larvae of the moth, Clepsis melaleucana (Black-Patched Clepsis), which feed on foliage or flowers; and larvae of the sawflies, Phymatocera racemosa and Phymatocera smilacinae, which feed on the foliage. The berries are eaten by the Greater Prairie Chicken and various woodland birds. White-Tailed Deer are quite fond of the foliage and will chomp off the tops of plants to about 6" above the ground. Photographic Location: Along a shady fence row near the webmaster's apartment complex in Urbana, Illinois, and a shaded wildflower garden at the University of Illinois in the same city.
Comments: The foliage of Solomon's Seal (Polygonatum commutatum) is attractive, while the flowers aren't very showy. Other Polygonatum spp. in Illinois have a similar appearance, but they are far less common. One species, Polygonatum pubescens (Pubescent Solomon's Seal) is pubescent on the undersides of its leaves (particularly along the veins), while the undersides of the leaves of Solomon's Seal are hairless. Another species, Polygonatum biflorum (Small Solomon's Seal), is slightly smaller in size with sessile leaves, while the leaves of Solomon's Seal clasp the central stem. There is an uncommon polyploid variant of Solomon's Seal that produces leafy stems about 3½-6' tall (or long) and its umbels often have more than 5 flowers. This variant is sometimes referred to as Giant Solomon's Seal. It prefers moist wooded areas, such as floodplain woodlands. Another group of plants with similar foliage, Smilacina spp. (False Solomon's Seal species), produce terminal panicles of flowers, while Polygonatum spp. (Solomon's Seal species) produce non-terminal umbels of flowers from the axils of their leaves.
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Miss Chen
2018年05月28日
Miss Chen
大花蕙兰是世界上最为常见的洋兰种类，是以附生性强的大花种问杂交而获得的人工杂交种。因其与蕙兰较相似，而且花朵大而得名。大花蕙兰花茎挺拔，花朵硕大，形态端庄，气势壮观，是世界上栽培最为普及的高档洋兰之一，备受人们青睐，在国际和国内兰花市场上享有很高的声誉。
一、病害：主要有疫病、软腐病、根腐病、炭疽病、叶枯病、毒素病等。 （一）、疫病： 疫病由于发生的部位不同和产生的病症不同，被分为黑腐病、心腐病、茎腐病、猝倒病等，在厦门地区一年四季均会发生。在温室栽培温度高、浇水过多、通气不良的情况下，叶梢中有大量水分，时间一长，最容易引发此病。每年的6-8月是发病的高峰期。从幼苗到开花株都能受害，特别是聚盘苗期和新生芽、心叶最容易受害。它是由两种密切相关的真菌?恶疫霉（PhytoPhthoracactoum）和终极腐霉（Pythiumwltmum）所引起。恶疫霉易引起根腐、猝倒、根颈腐烂，而终极腐霉也易引起植株的根腐和猝倒病。这些病一旦发生如不及时处理，则很快传染到根系、球茎，所以是大花蕙兰的可怕的毁灭病害，其传染途径系由孢子通过浇水时飞溅的水珠传播、扩散。 防治方法： 1、环境控制：兰棚要通风透气，光线要充足。发病时要严格控水，及时去除有病的病叶、病株，同时要避免由上而下喷水。 2、一旦发现染病植株，立即去除有病的组织，同时多切去未受感染的组织1寸左右，如受害严重的则整株去除。 3、剪刀等用具要严格消毒。 4、药剂处理：可用80％锌锰乃浦500倍溶液喷施。也可用1：2000的8一羟基喹啉硫酸盐喷洒，或将病株在邻苯基酚钠溶液中浸1小时，必要时可3至7天内进行重复处理。 （二）、软腐病： 软腐病通常侵害大花蕙兰的叶片、芽、球茎，一年中从春季到秋季都可能发生，冬天较少发现，有时常与疫病同时并发，但不太严重。它是由一种称为Erwiniachrysanthem的细菌引起的，其寄主范围很广，在兰科植物中都可以为害。其侵入途径主要是通过伤口或自然气孔。在高温多湿的兰棚，此病蔓延极快。在100％相对湿度、温度30℃时，采用人工接种后经过三小时之久，即完成入侵过程。其病症表现与疫病有些类似，使初养兰者很难判别。因这两种病在性质上不一样，用药也不同。在田间上我们的判别主要是根据拔出腐烂的病部进行观察：疫病的腐烂组织无汁液或少汁液，无鱼腥味的恶臭，把汁液挤一滴在一杯清水中，没有发现云雾状混浊物的扩散；而软腐病的病部表皮里的细胞都被分解成水液状液汁，内含有无数白色菌泥，汁液很多；轻轻一碰，汁液就流出来，同时有鱼腥味的恶臭，把汁液滴一滴在清水杯中，则可见有云雾状混浊物向四周扩散。 防治方法： l、环境控制与病株处理：同上第（一）条，特别注意勿使菌泥的汁液污染健康植株。 2、药剂处理：一般的农药对软腐病无效，所以一旦发病只好抛弃病株。因此主要是采取预防措施，用40％钢快得宁400倍液喷洒效果不错。也可以用68.8％多保链微素或18.8％链微素1000倍液，每隔7至10天喷洒1次，连续3至4次。这几种药品可采取轮流交交换使用，以免植株产生抗药性。 （三）、根腐病： 根腐病属于真菌病害；分布很广，除兰花外，其他植物也会受害；它是一种立枯丝菌RhizoctoniaSolaniKuehn引起的根腐烂。这也是大花蕙兰毁灭性病害之一。在大花蕙兰植株的任何生育期，不论是聚苗盆中的幼苗、中苗、大苗以及老熟的开花株都容易感染。其侵染的途径一般是由病苗的菌丝和菌核侵染兰花幼苗的根和根状茎造成的，如果不加控制，腐烂可发展到茎及较低部位的叶片。在侵染发展过程中，会形成一圈褐腐区，环绕植株基部引起幼苗死亡。成株受到侵害时，会逐渐衰弱。一般情况下腐烂只局限于根部，引起根部死亡；但有时腐烂也会扩大入侵到假鳞茎。使得根腐病的植株生长衰退，叶片和假鳞茎均发黄、瘦弱、扭曲、萎缩最终死亡。 防治方法： 1.环境控制与病株处理同上第（一）条。 2.药剂防治：?用苯来特1汤匙配水4千克浸根或浇施，效果不错。
（四）炭疽病： 炭疽病危害大花蕙兰的叶片；假鳞茎以及花萼、花瓣。它属于一种真菌的无性世代，一般是弱寄生性，往往发生在管理粗放的兰棚。兰株受伤害；如寒害、农药害、太阳灼伤以及氮肥施量过多、植料过酸或种植太密、通风不良、水分失调等造成根系不发达的弱株都容易受害。当病菌侵染兰花的叶片或假鳞茎时，首先看到的症状是出现褐色或黄绿色的长形不规则的污斑，稍凹陷，边缘清晰，成熟时，病斑上通常出现同心环纹，并在环斑上产生分生孢子。在受病组织与健全组织之间有明显分界线，后期病斑慢慢连接成片，覆盖面积逐渐增大，凹陷成坏死疽斑。 防治方法： 1.环境控制与病株处理同上第（一）条，种植密度要根据生长程度不同而改变，植料过酸要及时调配，pH值在5.8至6.6。 2.药剂防治：可用大富丹500倍溶液或大生45，500倍液喷洒，也可以用代森锰锌1000倍液喷洒，每周一次，连续三次。 （五）、叶枯病： 叶枯病是一种真菌病，发生在大花蕙兰叶尖附近或叶片的前端。初始产生黑色的小斑点，斑点渐渐扩大而成为不规则的病斑，病斑周缘形成黑褐色，中间成淡灰色，并有小黑点，严重时可蔓延整个叶面，最后枯死脱落。 防治方法：同上第（四）条 （六）、煤烟病： 煤烟病又称为煤污病，一般发生在粗放管理的兰棚，由于不通风人、光线不足兰株易受蚜虫、粉虱、介壳虫类等昆虫危害。这些昆虫在兰株上分泌一种蜜露沉积物，而煤烟病的真菌则附生在蜜露沉积物之上。它的症状常常在叶片的两面和假鳞茎上覆盖一层煤灰色的真菌，这种真菌对植株危害很小，因为它只是附生在表皮，可以与叶片、鳞茎分离，但由于这种病菌的覆盖会影响兰株的光合作用，同时也有碍观赏，降低兰花优美姿态，使兰花质量大降 防治方法： 1.环境控制同上第（一）条可用湿布擦拭病株发病部位，把表皮上附生的一层病菌去掉，叶片则恢复原状。 2.药剂防治：要防煤污病，首先必须控制和消灭蚜虫、粉虱和介壳虫类的发生，这些昆虫不存在，煤烟病也自然的不存在了。 （七）、毒素病： 大花蕙兰的毒素病也称为病毒病，是世界上发生最普遍的兰花病毒。由于病原体体积非常细小，在一般显微镜下无法看到，必须在电子显微镜下放大数万倍后，肉眼才能看到其形状其发病的症状，最常见的是植株的叶片和花朵灰绿并出现黄色的斑驳，最后成褐色凹陷的病斑，使植株叶片成为花叶，发育不良或开花不正常，一般发生在老茎分生苗的植株上。其传染途径往往是由于工具、分株和口吸式昆虫接触传染，以目前的水平尚无法治疗，一旦发现可疑的植株，应立即隔离或销毁处理。
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