Nitrogen deficiency is a deficiency of nitrogen in plants. This can occur when organic matter with high carbon content, such as sawdust, is added to soil. Soil organisms use any nitrogen available to break down carbon sources, making nitrogen unavailable to plants. This is known as "robbing" the soil of nitrogen. All vegetables apart from nitrogen fixing legumes are prone to this disorder.
Echinacea is a genus of herbaceous flowering plants in the daisy family. It has ten species, which are commonly called coneflowers. They are native only in eastern and central North America, where they grow in wet to dry prairies and open wooded areas. They have large, showy heads of composite flowers, blooming in summer. The generic name is derived from the Greek word ἐχῖνος, meaning "hedgehog", due to the spiny central disk. These flowering plants and their parts have different uses. Some species are cultivated in gardens for their showy flowers. Two of the species, E. tennesseensis and E. laevigata, were formerly listed in the United States as endangered species; E. tennesseensis has been delisted due to recovery and E. laevigata is now listed as threatened.
The London plane, or sometimes hybrid plane, Platanus × hispanica, is a tree in the genus Platanus. It is often known by the synonym Platanus × acerifolia, a later name. It is a hybrid of Platanus orientalis and Platanus occidentalis.
Solanum carolinense, the Carolina horsenettle, is not a true nettle, but a member of the Solanaceae, or nightshade family. It is a perennial herbaceous plant, native to the southeastern United States, though its range has expanded throughout much of temperate North America. The plant is an invasive in parts of Europe, Asia, Africa and Australia. The stem and undersides of larger leaf veins are covered with prickles.
Triadica sebifera is a tree native to eastern Asia. It is commonly called Chinese tallow, Chinese tallowtree, Florida aspen, chicken tree, gray popcorn tree, or candleberry tree.
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates through photosynthesis and may die unless the cause of its chlorophyll insufficiency is treated and this may lead to a plant disease called rusts, although some chlorotic plants, such as the albino Arabidopsis thaliana mutant ppi2, are viable if supplied with exogenous sucrose.
A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis. Symptoms can overlap across causal agents, however differing signs and symptoms of certain pathogens can lead to the diagnosis of the type of leaf spot disease. Prolonged wet and humid conditions promote leaf spot disease and most pathogens are spread by wind, splashing rain or irrigation that carry the disease to other leaves.
Rudbeckia is a plant genus in the Asteraceae or composite family. Rudbeckia flowers feature a prominent, raised central disc in black, brown shades of green, and in-between tones, giving rise to their familiar common names of coneflowers and black-eyed-susans. All are native to North America, and many species are cultivated in gardens for their showy yellow or gold flower heads that bloom in mid to late summer.
Centaurea solstitialis, the yellow star-thistle, is a species of thorny plant in the genus Centaurea, which is part of the family Asteraceae. A winter annual, it is native to the Mediterranean Basin region and invasive in many other places. It is also known as golden starthistle, yellow cockspur and St. Barnaby's thistle.
A frost flower or ice flower is formed when thin layers of ice are extruded from long-stemmed plants in autumn or early winter. The thin layers of ice are often formed into exquisite patterns, curling into "petals" which resemble flowers.
Echinacea purpurea, the eastern purple coneflower, purple coneflower, hedgehog coneflower, or Echinacea, is a North American species of flowering plant in the family Asteraceae. It is native to parts of eastern North America and present to some extent in the wild in much of the eastern, southeastern and midwestern United States, as well as in the Canadian Province of Ontario. It is most common in the Ozarks, the Mississippi Valley, and the Ohio Valley. Its habitats include dry open woods, prairies, and barrens.
Echinacea laevigata, the smooth purple coneflower, is a federally listed threatened species of plant found in the Piedmont of the eastern United States. Most populations are found on roadsides and other open areas with plenty of sunlight, often on calcium- and magnesium- rich soils.
Uromyces viciae-fabae var. viciae-fabae is a plant pathogen commonly known as faba-bean rust. The rust is distinguished by the typical rust-like marks on the stem and leaves, causing defoliation and loss of photosynthetic surface along with reduction in yield. The disease is fungal and is autoecious meaning it has one plant host. The rust of faba beans is macrocyclic, or contains 5 spores during its life cycle.
Strawberry foliar nematode, or strawberry crimp nematode, is a disease caused by Aphelenchoides fragariae, a plant pathogenic nematode. It is common in strawberries and ornamental plants and can greatly affect plant yield and appearance, resulting in a loss of millions of dollars of revenue. Symptoms used to diagnose the disease are angular, water soaked lesions and necrotic blotches. Aphelenchoides fragariae is the nematode pathogen that causes the disease. Its biological cycle includes four life stages, three of which are juvenile. The nematode can undergo multiple life cycles in one growing season when favorable conditions are present. The crowns, runners, foliage, and new buds of the plant via stylet penetration or through the stomata can be infected. The best management practices for this disease are sanitation, prevention of induction of the pathogen to the environment, and planting clean seed or starter plants.
Bangasternus orientalis is a species of true weevil known as the yellow starthistle bud weevil. It is used as an agent of biological pest control against the noxious weed yellow starthistle.
Linaria dalmatica is a herbaceous, short-lived perennial plant native to western Asia and southeastern Europe that has become a weed in other areas. The family this plant now belongs to is the Plantaginaceae Family. Previously, it belonged to the Scrophulariaceae (Figwort) family. Its common names include Balkan toadflax, broadleaf toadflax, and Dalmatian toadflax. Linaria dalmatica has unique yellow flowers with an orange center that draw individuals to purchase them to display in their gardens. The distribution of L. dalmatica to North America can be attributed to use as a fabric dye, folk remedies and as an ornamental plant. However, it is now classified as a weed in both Canada and the U.S.
Diabrotica balteata is a species of cucumber beetle in the family Chrysomelidae known commonly as the banded cucumber beetle. It occurs in the Americas, where its distribution extends from the United States to Colombia and Venezuela in South America. It is also present in Cuba. It is a pest of a variety of agricultural crops.
Botryotinia polyblastis is a fungal plant pathogen that causes Narcissus Fire of daffodils, genus Narcissus.
Verbesina alternifolia is a species of flowering plant in the family Asteraceae. It is commonly known as wingstem or yellow ironweed. It is native to North America.
