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Miss Chen
2018年05月27日
Miss Chen
煤污病又称煤烟病，在花木上发生普遍，影响光合、降低观赏价值和经济价值，甚至引起死亡。其症状是在叶面、枝梢上形成黑色小霉斑，后扩大连片，使整个叶面、嫩梢上布满黑霉层。由于煤污病菌种类很多，同一植物上可染上多种病菌，其症状上也略有差异。呈黑色霉层或黑色煤粉层是该病的重要特征。可以危害紫薇、牡丹、柑橘以及山茶、米兰、桂花、菊花等多种植物。
症状表现 由于煤污病菌种类很多，同一植物上可感染多种病菌，其症状上也略有差异。但总的来说，呈黑色霉层或黑色煤粉层是该病的重要特征。 该病主要危害叶片，也可危害枝和果实。初期在叶正面及枝条表面形成圆形黑色霉点，有的沿主脉扩展，以后逐渐增多，连接成片，使整个叶面、嫩梢上布满黑霉层。严重时导致植株提早落叶。 该病发生时常伴有蚜虫、介壳虫、粉虱等危害。病原属于真菌中知菌亚门的煤炱菌。病菌以菌丝体、分生孢子、子囊孢子形式在病叶、病枝等上越冬，成为次年的初侵染源。翌年孢子通过气流、风雨及蚜虫、粉虱、介壳虫等传播，并以这些害虫的分泌物及排泄物或植物自身分泌物为营养继续发育繁殖。 高温高湿、通风不良、隐蔽闷热及虫害严重的地方，煤污病害严重。每年3月至6月和9月至11月为发病盛期，湿度大发病重。盛夏高温病害停止蔓延，但夏季雨水多，病菌也会时有发生。
防治方法 加强栽培管理，种植密度要适当，及时修除病虫枝和多余枝条，增强通风透光，降低温度，及时排水，防止湿气滞留。 在保护地栽培花卉时，注意通风透光，降低湿度，盆花摆放要保持一定株行距，合理修剪。切忌环境湿闷，病轻时可用清水擦拭、冲洗。 该病发生与分泌蜜露的昆虫关系密切，喷药防治介壳虫、蚜虫、粉虱危害，是减少发病的主要措施。若为蚜虫危害，可在植株上先撒一层烟灰或草木灰，数小时后用清水冲洗干净，或用10％的吡虫啉可湿性粉剂2500倍液喷杀。若为粉虱类危害，可用25％的扑虱灵可湿性粉剂1500倍液喷杀。可喷洒10至20倍的松脂合剂及50％三硫磷乳剂1500至2000倍液以杀死介壳虫（在幼虫初孵时喷施效果较好）。 植物休眠期喷洒波美3至5度的石硫合剂，杀死越冬的菌源，从而减轻煤污病的发生。
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Miss Chen
2018年05月27日
Miss Chen
夏天对于植物而言是一个马虎不得的季节，常常有朋友说家里的花花草草不是这个黄叶了就是那个打蔫儿了，下面为大家整理了一些夏季比较典型的植物病症，如果你家的植物出现了这样的症状，一定要及时对症下药。 今年7月-8月危害荷花、睡莲、千屈菜、荇菜、碗莲、红蓼、蕺菜等水生花卉植物的病虫害预报，6种病虫害“榜上有名”。
莲窄摇蚊 被列入头号危害的是莲窄摇蚊，今年的爆发期预计在7月中旬到9月中旬。该病虫害危害的对象多是浮水、挺水植物类的浮叶、小立叶。被危害植物将显现不规则紫褐色斑点、斑块，影响观瞻。专家建议使用敌百虫、氧化乐果加以防治，同时注意控制水位。
茶黄蓟马 主要危害挺水、沼生类的立叶。这种害虫吸食植物叶液，造成叶片枯黄和茶褐色斑块，影响观赏效果。专家建议喷杀苏力菌后人工摘除受危害叶片。
莲缢管蚜 危害水生植物的嫩叶、嫩柄、花柄、花蕾，造成叶片卷缩枯黄，花蕾萎蔫干瘪。专家建议采取药剂喷杀、生物防治法，少量可人工捏死。
斜纹夜蛾 危害叶、花蕾，今年8月初预计将会爆发，建议用化学药剂毒杀，成虫用黑光灯诱杀。
腐败病 危害莲、荷类。初期叶缘变黄，渐干枯，卷曲枯死。建议用多菌灵，人工清除病株。
斑枯病 主要危害荷花、碗莲。病叶呈不规则棕色或褐色斑点。建议用多菌灵、代森锌，人工清除病株。 夏季养护小结 1、夏季为病虫害高发期，小飞虫，介壳虫，病菌感染等，日常养护需要注意湿度控制，卫生管理，定期对叶子进行清洗。 2、通常情况下，喜水花卉应勤浇水，喜干旱花宜少浇水，草本花卉含水量大，蒸腾快，浇水量要比木本花卉要多，同种植物塑料盆的比瓷盆的浇水要勤。 3、夏季植物缺水，水多不通风的情况很常见，注意夏天最好在早晚浇水，浇水后要保持室内空气流动。叶子和根部腐烂一般是水多，叶子干枯一般是缺水。
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Miss Chen
2018年05月27日
Miss Chen
白粉虱又名小白蛾子。属半翅目粉虱科。是一种世界性害虫，我国各地均有发生，是大棚内种植作物的重要害虫。可为害黄瓜、菜豆、豇豆、茄子、白菜、莴苣等多种蔬菜、花卉及农作物。该虫以成虫和若虫吸食植物汁液，使被害叶片褪绿、变黄、萎蔫。由于该虫繁殖速度快、繁殖力强，在18-21℃的情况下，约一个月就可繁殖一代，在北方一年可繁殖十余代，故一旦发生种群庞大，并群聚为害，还能分泌出大量蜜露，严重污染果实和叶片，引起煤污病的发生，使蔬菜等减产和失去商品价值。
由于白粉虱世代重叠，在同一时期同种作物上可同时存在各种虫态，而当今市场上所售药剂还没有发现对所有虫态都有效的农药，所以多数菜农对该害虫的防治均感头疼，只好加大药量和增加打药次数，并不断更换新农药，但仍收效甚微。长此以往，必然导致蔬菜的农药残留且逐渐超标。 为了达到菜农高产需要和市民需要无公害蔬菜的双重目的，笔者经过近年探讨，摸索出一个不用花一分钱就能除治白粉虱的好办法，去年在一个为害较重的菜园进行试验，获得了可喜的成果。 由于温室和露地蔬菜生产茬口衔接紧密和互相交替，白粉虱秋后从露地飞入温室为害繁殖，春天再通过温室通风开窗和菜苗向露地移植又迁入露地。所以白粉虱可周年发生。根据白粉虱在室外冬季不能存活的规律，笔者采取“关门打狗”让白粉虱以“安乐死”的方法死于室内，而后再清茬净地，具体办法如下。 1、严冬倒茬做杀机 利用冬季保护地蔬菜倒茬之机，严冬时节为杀虫适期。 2、拉秧清茬不着急 保护地秋冬茬菜采收结束后不急于拉秧净茬，免得打草惊蛇，使白粉虱逃入附近菜棚，而采取先闭棚提温，让白粉虱继续舒服的采食的方法。 3、热冷交替安乐死 闭棚后白粉虱很活跃，都积极栖息在植株上采食。于此日晚采取整棚不盖苫，傍晚在其它菜棚闭棚盖苫后打开该棚封口，让冷风直入，白粉虱不再迁飞，随深夜寒冷的到来，多数白粉虱在睡梦中冻死。次日若有未死的，再继续冷冻一夜，死亡率100%。 4、残杀手段全基地 随倒茬逐棚进行，杀虫方法棚棚如此。
相信养过植物的小伙伴们对白粉虱并不陌生，若家中有植物出来被白粉虱所祸害，那么就快试试以上方法吧。
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Miss Chen
2018年05月27日
Miss Chen
多菌灵防治病害范围及使用方 多菌灵又名棉萎灵、苯并咪唑44号。多菌灵是一种广谱性杀菌剂，对多种作物由真菌（如半知菌、多子囊菌）引起的病害有防治效果。可用于叶面喷雾、种子处理和土壤处理等。可以有效防治由真菌引起的多种作物病害，在我国的使用范围广泛，但其残留能引起肝病和染色体畸变，对哺乳动物有毒害。
防治对象和使用技术如下： 　 （1）防治果树病害： ①在梨树萌芽期和谢花后，用50%可湿性粉剂500倍液各喷雾1次，以后每隔7-10天喷1次，连续2-3次，可防治梨黑星病。 ②用50%可湿性粉剂500-800倍液，从苹果发病初期开始喷雾防治，7-10天后再喷1次，可防治苹果褐斑病。 ③从葡萄展叶后到果实着色前，每隔10-15天用50%可湿性粉剂500-1000倍液喷雾，对葡萄黑痘病、白腐病、炭疽病，防治效果良好。 （2）防治蔬菜病害： ①从病害初发期开始，用50%可湿性粉剂800-1000倍液，每隔7-10天喷雾防治1次，连喷3-5次，可防治番茄早疫病、瓜类白粉病、甜菜褐斑病。 ②黄瓜、西瓜等瓜类移栽定植前，每亩用50%可湿性粉剂1-1.5公斤，加细土25-30公斤拌匀，均匀地撒在定植沟或穴内，结瓜期再用50%可湿性粉剂1000倍液灌根，可防治瓜类枯萎病。 （3）防治棉花病害：用50%可湿性粉剂1公斤，对水10-20公斤，拌棉种100公斤，堆闷6小时后播种，或用50%可湿性粉剂250倍液浸种24小时，晾干播种，可防治棉苗立枯病、炭疽病。 （4）防治花生病害：用50%可湿性粉剂0.5-1公斤，花生种100公斤，拌匀后播种，可防治花生黑斑病、茎腐病等。 （5）防治小麦赤霉病：小麦抽穗盛期，用50%可湿性粉剂500-1000倍液喷雾，隔5-7天再喷1次。每次每亩喷药液75-100公斤。 （6）防治水稻纹枯病：用50%可湿性粉剂500-1000倍液，在水稻分蘖末期和孕穗期各喷雾防治1次。 （7）防治地瓜黑斑病：移栽前，用50%可湿性粉剂3000-4000倍液，浸渍地瓜苗茎基部5分钟。 （8）防治花卉病害：根据发病情况，用50%可湿性粉剂500-1000倍液喷雾，可防治各种花卉的白粉病以及月季褐斑病，君子兰叶斑病，兰花炭疽病、叶斑病等。
使用注意事项： 对人、畜、鱼类、蜜蜂等低毒。 对皮肤和眼睛有刺激，经口中毒出现头昏、恶心、呕吐。
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Miss Chen
2018年05月26日
Miss Chen
Description: This perennial wildflower is up to 2½' tall and across. Its central stem (and any side stems) is pale green to pale purplish green, terete, glabrous, and glaucous. The alternate compound leaves are double or triple odd-pinnate, spanning up to 1' long and across. Each branch of a compound leaf has 3 or 5 leaflets; like the central stem, the branches of the compound leaves are pale green to pale purplish green, glabrous, and glaucous. Individual leaflets are up to 1¾" long and across; they are reniform-orbicular to oval-orbicular in shape with 3-9 terminal lobes (usually 5 or more). These short lobes are well-rounded or bluntly pointed. The upper surface of each leaf is medium green and smooth, while the lower surface is pale green with a conspicuous network of raised veins; both sides are hairless. All of the leaflets have slender petioles. The central stem terminates in a large floral panicle up to 1' tall and across; each branch of the panicle terminates in a corymb of about 5 flowers. Because Early Meadow Rue is dioecious, some plants produce all male (staminate) flowers, while other plants produce all female (pistillate) flowers. The male flowers droop downward from their branches to a greater extent than the female flowers. Each male flower is about ¼" across and ½" long; it consists of 4-5 sepals and 10 or more stamens. The sepals are broadly oblong, pale green, light-veined, and white-margined; the stamens have long yellow anthers and slender filaments. Each female flower is about the same size as the male flower; it consists of 4-5 sepals and up to 15 pistils. The sepals are similar to those of the male flowers, while the pistils are grey with flat-sided styles. Neither male nor female flowers have petals. The blooming period occurs from mid- to late spring. Cross-pollination is by wind and there is no floral fragrance. The male flowers soon wither away, while the fertile female flowers are replaced by ellipsoid achenes that are pointed at both ends and strongly ribbed. After flowering plants die down during the summer, low basal leaves develop during the fall. Their appearance is similar to the alternate compound leaves, as described above. The root system is fibrous and rhizomatous. This wildflower can reproduce by its rhizomes or achenes.
Cultivation: The preference is light shade, mesic conditions, and a loam or clay-loam soil. Most vegetative growth occurs during the spring and early summer. Range & Habitat: The native Early Meadow Rue is occasional in eastern central and northern Illinois, but it is uncommon or absent elsewhere in the state (see Distribution Map). Habitats include rich mesic woodlands, wooded clay slopes, shaded areas near cliffs, and rocky ravines. In Illinois, this species is typically found in Maple-Basswood woodlands. It blooms before the canopy trees have fully developed their leaves. Faunal Associations: The caterpillars of the following Noctuid moths feed on Thalictrum spp. (Meadow Rue species) – Calyptra canadensis (Canadian Owlet), Papaipema unimoda (Borer Moth sp.), and Pseudeva purpurigera (Straight-Lined Looper Moth). White-Tailed Deer browse on the foliage of Early Meadow Rue sparingly.
Photographic Location: A mesic woodland in east-central Illinois. The photographed plant is staminate (male). Comments: Early Meadow Rue is shorter in stature and blooms earlier than other Thalictrum spp. in Illinois. It also has greater fidelity to shady woodlands as a habitat. All of these species have elegant foliage and unusual wind-pollinated flowers. The male flowers of Early Meadow Rue are more showy than the female flowers; this is primarily because the anthers of the male flowers are yellow, while the styles of the female flowers are dull-colored. The leaflets of Early Meadow Rue have more terminal lobes (usually 5-9) than the leaflets of other Thalictrum spp. in the state (usually 3-5). Because of this distinctive characteristic, it is easy to identify.
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Miss Chen
2018年05月26日
Miss Chen
Description: This herbaceous perennial plant is 2–3½' tall, branching occasionally in the upper half. It is more or less erect, although the weight of the inflorescence often causes the entire plant to lean sideways. The slender stems are light green, terete, and either glabrous, sparsely pubescent, or hairy in lines. The alternate leaves are up to 6" long and 2" across, becoming gradually smaller as they ascend the stems. The petioles are very slender and about 1" long on the lower leaves, while the upper leaves are nearly sessile. The petioles are light green and often hairy. The lower to middle leaves are lanceolate-ovate with indented bases, while the upper leaves are lanceolate with rounded bases. All leaves taper gradually into slender acute tips, while their margins are smooth and often slightly ciliate. The upper leaf surface is medium green and glabrous (or nearly so), while the lower leaf surface is light green and either sparsely pubescent, hairy along the central vein, or glabrous. The lower leaf surface also has a reticulated network of fine secondary veins. The central stem (and any upper lateral stems) terminates in a panicle of flowerheads up to 1½' long and ¾' across. Each flowerhead is about ¾–1" across, consisting of 10-20 ray florets that surround a similar number of disk florets. The petaloid rays of these flowerheads are lavender or pale blue-violet (rarely white), and they are individually linear-oblong in shape. The corollas of the disk florets are short-tubular with 5 minute lobes at their apices. Initially, these corollas are yellow, but they become reddish purple with age. On unusual specimens, these corollas are light pink to nearly white. At the base of each flowerhead, the overlapping phyllaries (scaly floral bracts) are linear-lanceolate and glabrous to finely pubescent. Depending on the stage of their maturity, the phyllaries have patches of dark green that are diamond-shaped near their tips, or they have central veins that are dark green. Otherwise, the phyllaries are light green. The blooming period occurs from late summer through the fall, lasting about 1–1½ months. Both the ray and disk florets can produce fertile achenes. These achenes are 2-3 mm. long and oblongoid in shape; they have small tufts of light brown hair at their apices. As a result, the achenes are distributed primarily by the wind. The root system is fibrous and rhizomatous; older plants sometimes develop a small caudex. Clonal colonies of plants can develop from the rhizomes.
Cultivation: The preference is partial sun, mesic to dry-mesic conditions, and soil that contains loam or some rocky material with decaying organic matter. Calcareous ground with a higher than normal pH is tolerated. Like many other asters (Symphyotrichum spp.), the foliage can be attacked by many kinds of insects and disease organisms. The plants have a tendency to flop over while in bloom. Range & Habitat: The native Short's Aster is a fairly common species that occurs in the majority of counties in Illinois. However, it is less common in some southern areas of the state (see Distribution Map). Habitats include mesic to upland woodlands, rocky open woodlands and slopes, limestone bluffs, woodland borders, and areas along woodland paths. Short's Aster occurs in both oak-hickory woodlands and maple-basswood woodlands. This aster often occurs in areas where limestone is close to the surface of the ground; it is usually found in higher quality natural areas. Wildfires and other kinds of disturbance can be beneficial if they reduce excessive shade from overhead canopy trees, or they reduce competition from invasive shrubs.
Faunal Associations: The flowerheads of asters (Symphyotrichum spp.) attract many kinds of insects, especially long-tongued bees, small-tongued bees, butterflies, skippers, and flies. These insects obtain nectar or pollen from the flowerheads. Some bees are specialist pollinators of asters and sometimes goldenrods (Solidago spp.); these species include the plasterer bee Colletes simulans armata, and such Andrenid bees as Andrena asteris, Andrena asteroides, Andrena hirticincta, Andrena nubecula, Andrena simplex, and Andrena solidaginis. The caterpillars of two butterflies, Chlosyne nycteis (Silvery Checkerspot) and Phyciodes tharos (Pearl Crescent), feed on the foliage of asters. In addition, the caterpillars of such moths as Cucullia asteroides (The Asteroid), Carmenta corni (Aster Borer Moth), and many others feed on various parts of asters (see Moth Table). Other insect feeders include Exema canadensis and other leaf beetles, larvae of Calycomyza humeralis (Aster Leafminer Fly), larvae of several fruit flies, many aphids (especially Uroleucon spp.), Macrosteles fascifrons (Aster Leafhopper), the plant bug Plagiognathus cuneatus, and Corythucha marmorata (Goldenrod Lace Bug). Among birds, the Wild Turkey and Ruffed Grouse occasionally eat the seeds and foliage of these plants in woodland areas. Among mammals, both the White-tailed Deer and Cottontail Rabbit undoubtedly feed on the rather smooth foliage of Short's Aster and similar asters.
Photographic Location: A woodland edge near Busey Woods in Urbana, Illinois. Comments: This is one of the more attractive woodland asters with flowers that are larger than average in size. Short's Aster (Symphyotrichum shortii) can be distinguished from other asters (Symphyotrichum spp.) by carefully considering the appearance of the foliage and flowerheads. The lower to middle leaves of Short's Aster are indented at the base with narrow petioles. Some asters, such as Symphyotrichum sagittifolium (Arrow-Leaved Aster), have winged petioles on their lower to middle leaves, while other asters have rounded or wedge-shaped bases on their lower to middle leaves. The margins of leaves in Short's Aster are devoid of teeth (or nearly so), while other woodland asters, such as Symphyotrichum cordifolium (Blue Wood Aster), have leaf margins with conspicuous teeth. Similarly, the upper leaf surface in Short's Aster is hairless (or nearly so), while the upper leaf surface of Symphyotrichum drummondii (Drummond's Aster) is pubescent. Finally, the flowerheads of Short's Aster are usually ¾" across or more, while the flowerheads of other woodland asters are usually less than ¾" across. A scientific synonym of this species is Aster shortii.
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Miss Chen
2018年05月26日
Miss Chen
Description: This perennial wildflower is 2-3½' tall, sending up one or more leafy stems during the late spring. Initially, these stems are erect to ascending, but later in the year they sometimes sprawl across the ground. These stems are unbranched below and occasionally branched above; they are light green to reddish brown, terete, glabrous below, and lined with short hairs above. The alternate leaves are up to 4" long and 2½" across, becoming smaller as they ascend the stems. The lower leaves are cordate to cordate-ovate in shape and coarsely serrated to crenate-serrate along their margins. The upper leaves are cordate-ovate to ovate in shape and crenate-serrate to slightly crenate-serrate along their margins. The petioles are up to one-half the length of the blades, becoming relatively shorter as they ascend the stems; these petioles are conspicuously winged along their margins and they are often ciliate or slightly pubescent. The upper surfaces of the leaves are glabrous to sparsely covered with short hairs, while their lower surfaces are usually glabrous, except for some fine hairs along the major veins. However, some young leaves may have sparse short-pubescence on their lower surfaces. The central stem and upper lateral stems (if any) terminate in panicles of flowerheads that are ¾-1¾' long and about one-half as much across. The lateral branches of these panicles are ascending; the peduncles of the flowerheads are short (up to ½" in length). The central stalk, lateral branches, and peduncles are light green to reddish brown, terete, and either glabrous, short-pubescent, or lined with short hairs. Each flowerhead is about ½" across, consisting of about 8-15 ray florets that surround 8-12 disk florets. The petaloid rays of the flowerheads are lavender, light blue-violet, or white. The corollas of the disk florets are initially cream-colored or yellow, but they later become reddish purple. Around the base of each flowerhead, there are phyllaries (scale-like floral bracts) in several overlapping series; individual phyllaries are 2-5 mm. in length. Individual phyllaries are linear-lanceolate to narrowly lanceolate, appressed together or slightly spreading, and they have dark green patches near their tips that are diamond-shaped. Leafy bracts up to 1" long occur along the central stalks and lateral branches of panicles; they are linear-oblong or elliptic in shape and entire (smooth) along their margins. The blooming period occurs from late summer into the autumn and lasts about 1-3 months. Afterwards, the florets are replaced by achenes with small tufts of hair; they are distributed by the wind. The achenes are 2.0-2.5 mm. long, oblongoid-oblanceoloid in shape, and brown to purplish brown. The root system is fibrous and short-rhizomatous; an older plant may develop a small woody caudex. This wildflower spreads by reseeding itself and by forming clonal offsets from the rhizomes. A rosette of semi-evergreen basal leaves is created during the autumn that can persist until the spring. These basal leaves are ¾-3" long, cordate-ovate in shape, and crenate-serrated along their margins. Their upper surfaces are medium green and glabrous, while their lower surfaces are pale green and glabrous to finely hairy along the major veins. The petioles are about the same length as the corresponding basal leaves; they are narrow or slightly winged.
Cultivation: The preference is partial sun, mesic to dry conditions, and soil that contains loam, clay-loam, or rocky-loam. The leaves may become yellowish green when they are exposed to bright sunlight; the lower leaves may become wilted and fall off their stems during hot dry weather. Sometimes powdery mildew attacks the leaves during the late summer or fall when moisture is abundant. Range & Habitat: The native Arrow-Leaved Aster is common in most areas of Illinois, except some counties in the south-central area of the state (see Distribution Map). Habitats include upland woodlands, rocky woodlands, wooded slopes, thinly wooded bluffs, woodland edges, savannas, rocky glades, grassy thickets, small meadows in wooded areas, and edges of yards. This aster tolerates disturbance to some extent.
Faunal Associations: The nectar and pollen of the flowerheads attract many kinds of insects, including long-tongued bees, short-tongued bees, Syrphid flies, bee flies, wasps, and occasional butterflies or skippers. Caterpillars of the butterflies Chlosyne nycteis (Silvery Checkerspot) and Phyciodes tharos (Pearl Crescent) feed on the foliage of asters (Symphyotrichum spp.), while the caterpillars of many moths feed on the foliage, flowerheads, developing seeds, stems, or roots (see Moth Table). Other insect feeders include leaf beetles, lace bugs, plant bugs, stink bugs, aphids, leafhoppers, and the larvae of leaf-mining flies and fruit flies (see Insect Table for a list of these species). Among vertebrate animals, the Wild Turkey and Ruffed Grouse occasionally eat the seeds and young foliage of asters, while such mammalian herbivores as deer, rabbits, groundhogs, and livestock browse on the foliage. Photographic Location: Border of a wooded area at Crystal Lake Park in Urbana, Illinois.
Comments: Arrow-Leaved Aster (Symphyotrichum sagittifolium) is one of several woodland asters with relatively small flowerheads that have cordate or cordate-ovate lower leaves. While the leaves can become rather coarse, the panicles of abundant flowerheads are often showy. This species has an appearance that is similar to Drummond's Aster (Symphyotrichum drummondii), Heart-Leaved Aster (Symphyotrichum cordifolium), and White Arrowleaf Aster (Symphyotrichum urophyllum), which occur in similar habitats. Drummond's Aster has stems and leaf undersides that are evenly pubescent, while the stems of Arrow-Leaved Aster are either glabrous or they are lined with hairs, and the undersides of its leaves are either glabrous or they have fine hairs along the major veins. Heart-Leaved Aster can be distinguished by the narrow petioles of its alternate leaves, while those of Arrow-Leaved Aster are conspicuously winged. Sometimes the latter is considered a variety of Heart-Leaved Aster, or Symphyotrichum cordifolium sagittifolium (Jones, 1989). Finally, Arrow-Leaved Aster and White Arrowleaf Aster are regarded as the same species by some authorities (e.g., efloras, USDA, and ITIS), while Mohlenbrock (2014) considers them to be distinct. An argument for the latter point-of-view can be made as, compared to Arrow-Leaved Aster, White Arrowleaf Aster has more narrow upper leaves (typically ovate to lanceolate), the margins of its leaves are less strongly toothed or they lack teeth, and its phyllaries have green central stripes, rather than diamond-shaped patches of dark green toward their tips. In addition, the petaloid rays of this latter aster are almost always white. All species in this complex of asters were assigned orginally to the Aster genus.
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Miss Chen
2018年05月26日
Miss Chen
Description: This perennial wildflower is 1½–3' tall. Each plant has a central stem that develops from the rootstock (less often, there are 2-3 such stems), which branches from below the middle. During the flowering period, short secondary stems develop from the axils of the leaves. These stems are terete, mostly light green, and pubescent; sometimes they have longitudinal ridges. The alternate leaves are up to 3½" long and 1" across; they are lanceolate, oblanceolate, or narrowly ovate with margins that are slightly toothed or smooth. The upper surface of each leaf is medium green and hairless, while the lower surface is light green and finely short-pubescent. Sometimes there are longer hairs along the central vein on the underside of each leaf. The leaves are sessile against their stems and their outer tips are somewhat blunt. The upper stems terminate in elongated panicles of flowerheads. Each flowerhead spans about ½" across, consisting of 15-25 white ray florets and a similar number of disk florets. The disk florets are initially pale yellow, but they later become reddish purple; each disk floret is tubular in shape with 5 spreading lobes along its upper rim. Surrounding the base of each flowerhead, there is an overlapping series of small floral bracts (phyllaries). These floral bracts are linear in shape, evenly green from top to bottom, and appressed or slightly spreading. Each flowerhead has a short peduncle up to 1" long. In addition to the flowerheads, the branches of the panicle have numerous leafy bracts. These leafy bracts are similar in appearance to the leaves, except smaller in size. The blooming period occurs from late summer into the fall and lasts about 1-2 months. Each flowerhead is replaced by a dense cluster of small achenes. Each achene is bullet-shaped with a small tuft of white hairs at its apex. The achenes are distributed by the wind. The root system is fibrous and long-rhizomatous. Small colonies of plants are occasionally formed. Cultivation: The preference is partial or dappled sunlight, moist to mesic conditions, and a fertile loamy soil. Other kinds of soil are also tolerated.
Range & Habitat: The native Ontario Aster is occasional to locally common throughout Illinois (see Distribution Map). Habitats include open woodlands, woodland openings, woodland borders, partially shaded cliffs, areas along woodland paths, powerline clearances in wooded areas, low areas along woodland streams, savannas, moist meadows, and abandoned fields. This aster benefits from disturbance if it reduces excessive shade from canopy trees. Faunal Associations: The nectar and/or pollen attract various insects, including bumblebees, little carpenter bees (Ceratina spp.), leaf-cutting bees (Megachile spp.), Halictid bees, Syrphid flies, and butterflies. A long-horned bee, Melissodes dentriventris, is an oligolectic floral visitor of this and other asters (Symphyotrichum spp.). These insects cross-pollinate the flowers. Other insects, including aphids, plant bugs, leaf beetles, etc., feed destructively on asters (see Insect Table); there are also a large number of moth caterpillars that feed on various parts of asters (see Moth Table). The Ruffed Grouse and Wild Turkey feed on the leaves and seeds of these plants to a limited extent; White-Tailed Deer and Cottontail Rabbits also feed on the foliage to a limited extent. Photographic Location: A powerline clearance at Busey Woods in Urbana, Illinois. Comments: This aster has a rather ordinary appearance and it is often omitted in many wildflower guides. Ontario Aster (Symphyotrichum ontarionis) resembles several other asters (Symphyotrichum spp.) with small white flowerheads and they often occur in the same or similar habitats. In general, Ontario Aster can be distinguished from these other species by the even pubescence of its stems and the even canescence (short fine pubescence) on the underside of its leaves. Other similar asters have stems with lines of hair and the undersides of their leaves are either hairy along the major veins or hairless. The flowerheads of Ontario Aster have 15-25 ray florets and its floral bracts are evenly green from top to bottom. Other similar asters have fewer ray florets (10-15) or their floral bracts have a diamond-shaped pattern near their tips that is dark green. Ontario Aster also has an abundance of leafy green bracts along the branches of its panicles, while the bracts of other asters are smaller in size and more scale-like in appearance. Sometimes Ontario Aster hybridizes with similar species of asters, which increases the difficulty of identification. A scientific synonym of this species is Aster ontarionis.
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Miss Chen
2018年05月26日
Miss Chen
Description: This perennial wildflower consists of a small rosette of basal leaves about 3-8" across, persisting from autumn to spring. These basal leaves are semi-evergreen, ¾-2½" long, and ½-2" across; they are oval-cordate in shape and their margins are crenate-serrate. The upper surfaces of basal leaves are medium green and sparsely to moderately short-pubescent, while their lower surfaces are light green and moderately to densely short-pubescent. Exposure to near-freezing temperatures sometimes causes the basal leaves to turn purple. The petioles of basal leaves are up to 2" long, slender, and short-pubescent. This wildflower bolts during the late spring to produce one or more leafy stems about 1½-3¼' long that are initially erect or ascending, although tending to sprawl across the ground later in the year. These stems are light green to purple, terete, and short-pubescent to pubescent throughout; this pubescence is not restricted to longitudinal lines. The stems are unbranched below, while they are sparingly to occasionally branched above. Alternate leaves occur along these stems that are 1-4" long and ½-3" across (becoming smaller in size as they ascend the stems); they are cordate below, becoming cordate-ovate to lanceolate above. The margins of these alternate leaves are coarsely serrated below, becoming serrated to slightly crenate-serrate above. The upper surfaces of these leaves are moderate green and sparsely short-pubescent to densely short-pubescent, while their lower surfaces are light green and moderately to densely short-pubescent or pubescent throughout; this pubescence is not restricted to the major veins. When these leaves are exposed to bright sunlight, they may become yellowish green. Leaf texture tends to be stiff and rough. The petioles of alternate leaves are ½-2" long and their margins are more or less winged; they are moderately to densely short-pubescent. Sometimes small secondary leaves appear in the axils of these leaves. Each leafy stem terminates in a panicle of flowerheads about ½-2' long and about one-half as much across. In addition to the central stalk of the panicle, there are several ascending lateral branches along which most of the flowerheads occur on short peduncles (less than ½" long). The central stalk, branches and peduncles are light green to purple, terete, and evenly short-pubescent to pubescent.
Each flowerhead is about ½" across, consisting of 10-15 ray florets that surround 10-15 congested disk florets. The petaloid rays of these flowerheads are usually lavender or light violet (less often white) and linear-oblong in shape. The short-tubular disk florets are initially cream-colored to yellow, but they later become reddish purple. Each disk floret has 5 short lobes that are erect. Around the base of each flowerhead, the scale-like phyllaries (floral bracts) are arranged in several overlapping series; these phyllaries are appressed together, or nearly so. Individual phyllaries are 4-6 mm. in length, linear-lanceolate in shape, and light green, except for diamond-shaped patches of dark green near their apices. Leafy bracts occur along central stalk and lateral branches of the panicle that are up to 1" long and elliptic to linear-oblong in shape; they are slightly toothed to entire (smooth) along their margins. The blooming period occurs from late summer into autumn for 1-3 months. Afterwards, the florets are replaced by achenes with small tufts of white hair. The achenes are 2-3 mm. long, oblongoid-oblanceoloid in shape, slightly ribbed, and light to medium brown (sometimes with reddish or purplish tints). They are distributed by the wind. The root system is fibrous and short-rhizomatous. On older plants, a small woody caudex may develop. Clonal offsets are often produced from the rhizomes.
Cultivation: The preference is partial sun, mesic to dry-mesic conditions, and soil containing loam, clay-loam, or some rocky material. This wildflower is usually easy to cultivate. The foliage may become discolored with age; lower leaves may wither away in response to hot dry conditions. There is a tendency for the flowering stems to sprawl across the ground during the autumn. Range & Habitat: The native Drummond's Aster is common in central and northern Illinois, while in the southern section of the state it is occasional to locally common (see Distribution Map). Habitats include upland woodlands, rocky woodlands, woodland openings, woodland borders, areas along woodland paths, disturbed open woodlands, upland savannas, thinly wooded bluffs, powerline clearances through wooded areas, thickets, partially shaded riverbanks, burnt-over vacant lots, edges of yards, and partially shaded areas along roadsides. Drummond's Aster can be found in both high quality natural areas and degraded sites. Occasional wildfires are beneficial when they reduce excessive shade from overhead canopy trees. The woodlands where this aster occurs are dominated by various deciduous trees, especially oaks (Quercus spp.).
Faunal Associations: The flowers are cross-pollinated by honeybees, bumblebees, Halictid bees (including green metallic bees), Andrenid bees, miscellaneous wasps, Syrphid flies, Tachinid flies, Muscid flies, butterflies, skippers, moths, and other insects. Both nectar and pollen are available as floral awards to such visitors. The following bees are oligolectic visitors (pollinator specialists) of aster flowers: Andrena asteris, Andrena asteroides, Andrena hirticincta, Andrena nubecula, Andrena solidaginis, and Colletes simulans armata. Some of these oligoleges also visit goldenrod flowers. Other insects that are associated with Drummond's Aster and other asters (Symphyotrichum spp.) include leaf beetles, larvae of fruit flies and leaf-mining flies, plant bugs, lace bugs, stink bugs, aphids, leafhoppers, walkingsticks, caterpillars of butterflies, and caterpillars of many moths. These insects feed destructively on the leaves, flowers, developing seeds, stems, roots, or plant juices (see the Insect Table and Moth Table for more information about these species). In general, asters are less important to vertebrate animals. However, such upland gamebirds as the Ruffed Grouse and Wild Turkey feed occasionally on the foliage and seeds; such mammals as deer, rabbits, groundhogs, and livestock also feed on the foliage.
Photographic Location: Edge of a wooded area at Crystal Lake Park in Urbana, Illinois. Comments: Drummond's Aster (Symphyotrichum drummondii) is part of a complex of similar species involving Arrow-Leaved Aster (Symphyotrichum sagittifolium), Heart-leaved Aster (Symphyotrichum cordifolium), and White Arrowleaf Aster (Symphyotrichum urophyllum). There has been a history of taxonomic instability involving the interrelationships between these 4 species. Some of these species are considered varieties of each other by some taxonomists, or they have been merged with other species within this complex. Drummond's Aster can be distinguished from other species (or varieties) in this complex by the evenly distributed pubescence along its stems and by the evenly distributed pubescence on the lower sides of its leaves. The abundance and conspicuousness of this pubescence can vary across different populations of plants in Illinois. Drummond's Aster also differs from Heart-leaved Aster by its winged petioles; this is a trait that it shares with the remaining species of this complex. Relatively recently, all of these species have been assigned to the Symphyotrichum genus; Drummond's Aster was referred to previously as Aster drummondii. While the individual flowerheads are relatively small, the inflorescence of this aster is often quite large and showy during the autumn.
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Miss Chen
2018年05月26日
Miss Chen
苏粉蚧别名柑桔臀纹粉蚧、柑桔粉炒。该虫食性杂，牡丹、菊花、十字景天、柑桔、棕榈等多种药用植物及果树均可受其害。成、若虫群集在嫩梢吸食汁液，造成梢叶枯萎或畸形早落，有时诱发煤污病。分布辽宁、山西、山东、江苏、上海、浙江、福建、湖北、广东、四川等省。北方主要发生在温室。
寄主 牡丹、菊花、茶花、君子兰、风仙花、常春藤、十字景天、变叶木、柑桔、棕榈等多种药用植物及果树。 为害特点 成、若虫群集在嫩梢吸食汁液，造成梢叶枯萎或畸形早落，有时诱发煤污病。 形态特征 雌成虫体长2．5mm，黄褐色至青灰色，椭圆形，上被白蜡粉。体四周有白色蜡丝18对，尾端长。触角8节。后期背部显现出1条青灰色纵纹。雄成虫体长1．6mm，触角9节，眼红色，体被白蜡粉，体末有白色蜡丝2根。卵长0.3mm，椭圆形，初浅黄色，后变橙黄色。若虫共3龄。3龄若虫体长1．1mm，周缘的18对蜡丝已形成，触角7节。雄蛹长1．1mm，橙色，眼红色。茧椭圆形，白色。 生活习性 上海温室内年生3代，以受精雌成虫和部分带卵囊成虫于顶梢处或枝干分权处、裂缝中越冬。翌年4月中旬开始产卵，4月下旬?5月上旬进入产卵盛期，第1代若虫于4月中旬一6月下旬出现，1代雌成虫于5月下旬始见，6月中、下旬进入羽化盛期。2代以后发生期不整齐，至11月中下旬开始越冬。
防治方法 (1)加强检疫，防止该虫进入药圃或药园。 (2)加强管理，注意通风透光，防止该虫大量繁殖。 (3)必要时用40％乐果乳油1000倍液灌根有效。
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