User talk:SarahNicoleTaylor-3

October 2012
Hello. There is currently a discussion at Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. Thank you. Amp71 (talk) 01:19, 25 October 2012 (UTC)

You have been blocked from editing for a period of 1 week for abusing multiple accounts, as you did at Ditylenchus dipsaci. Once the block has expired, you are welcome to make useful contributions. If you think there are good reasons why you should be unblocked, you may appeal this block by adding below this notice the text, but you should read the guide to appealing blocks first. Bbb23 (talk) 01:53, 25 October 2012 (UTC)

Someone at the administrators' noticeboard suggested that you might want to write your draft in a sandbox page (eg, User:SarahNicoleTaylor-3/Draft) and then move it to the main article when you're finished. That way the main article isn't left in a state of disruption while you work on the new content. Is this acceptable? There is also a second issue that there appears to be multiple people editing from usernames which are very similar (SarahNicoleTaylor, SarahNicoleTaylor-3 and SarahNC). This is slightly confusing and unhelpful, so it would be good for you to clarify how many of you there are and if any accounts are being operated by the same person. Thanks. – Steel 03:21, 25 October 2012 (UTC)
 * I have unblocked your friends SarahNicoleTaylor and SarahNC, but not this account because its username is misleadingly similar to SarahNicoleTaylor. You should be able to log out and create a new username without any problems. – Steel 12:17, 25 October 2012 (UTC)


 * Can you please clarify the following? Are you saying that the three accounts actually belong to different people? If so, all using usernames based on "Sarah Nicole Taylor" is highly misleading, as it gives the impression that you are all the same person. If Sarah Nicole Taylor is a real person and you are someone else, then you must not continue to edit using that name, as it infringes Wikipedia's WP:User name policy, which says "Do not edit under a name that is likely to imply that you are ... a specific, identifiable person, unless it is your real name." Even if the name "Sarah Nicole Taylor" is fictitious, the usernames fall foul of that policy, because usernames that are very similar to existing ones are unacceptable because of the risk of being misleading. If you are three different people, then make that fact clear, and suggest a new username that you are willing to use. You may then be unblocked to allow you to submit a request to have your username changed. JamesBWatson (talk) 11:57, 25 October 2012 (UTC)

Stem and Bulb Nematode - Ditylenchus dipsaci
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Summary
Ditylenchus dipsaci is a plant pathogenic nematode which primarily infects onion and garlic. It is commonly known as the stem nematode, the stem and bulb eelworm or onion bloat (in the United Kingdom). Symptoms of infection include stunted growth, discoloration of bulbs, and swollen stems. D. dipsaci is a migratory endoparasite that has a five stage life cycle and the ability to enter into a dormancy stage. D. dipsaci enter through stoma or wounds and create galls or malformations in plant growth. This allows for the entrance of secondary pathogens like fungi and bacteria. Management of disease is maintained through seed sanitation, heat treatment, crop rotation, and fumigation of fields. Stem and bulb nematode is economically detrimental because infected crops are unmarketable.

Hosts and Symptoms
The stem and bulb nematode Ditylenchus dipsaci has an extensive host range. Major damage occurs on garlic, onion, carrot, faba beans, alfalfa, oats, and strawberry. Ornamental plants can also be infected including hyacinth and tulip. It is estimated that this pathogen infects 400-500 plant species worldwide.

In Allium species (onions, garlic, and leeks), infected plants show characteristic symptoms including stunted growth, yellow spots, leaf curl, and foliage lesions. Stems often have swollen regions called “spikkles.” As adult nematodes migrate into the scales of the bulb, scales become soft, grey, and loosely packed. Highly infected bulbs can also split apart or show malformed bloating. The leaves of the plant become flaccid and may collapse. This can lead to defoliated plants. Garlic shows similar symptoms of leaf yellowing and stunted bulbs. When harvested, the infected garlic may be missing portions of the root system.

On faba beans, Vicia faba, symptoms of infection include reddish-brown stem lesions that can turn black in color. Young bean pods are dark-brown in color. Infected seeds are smaller and distorted compared to healthy beans. Speckles and spots are also commonly seen on infected faba beans.

There up to 30 biological races within Ditylenchus dipsaci that are mostly distinguished by their host preferences. There is very little morphological differences between the races which makes diagnosis difficult. Seed material samples from infected plants can be dissected and viewed under under a microscope to confirm the pathogen.

Life Cycle
Stem and bulb nematodes are migratory endoparasites. Their life cycle occurs in five stages with the first molt occurring in the egg and the 2nd and 3rd occurring in the soil. By the fourth stage juveniles have entered the plant through young tissue and/or seedlings. The fourth molt will then occur inside the plant. The adult female must mate with a male to reproduce and lay eggs. A complete reproductive life cycle of the stem and bulb nematode is 19-25 days (egg to egg). Reproduction takes place in succulent, rapidly growing tissues or in storage organs and continues throughout. A female can lay 200-500 eggs in her lifespan. However if conditions are unfavorable the nematodes can halt their life cycle. The life span of stem and bulb nematodes is approximately 70 days. Most generations are passed inside bulbs, stems and leaves. Eggs and larvae overwinter in dried infected host material. They are also found in weed hosts and seeds of composite. Stem and bulb nematode can survive up to 2 years in freezing or extremely dry environments in the soil. Nematodes can survive on or in plant tissue by entering cryptobiosis (hidden life) and survive for 3-5 years in this stage. During dormancy nematodes show no sign of life and the metabolic activity is almost at a standstill.

Disease Cycle
Stem and bulb nematodes are migratory endoparasites and can be spread through irrigation water, tools and animals. When the plants are covered in a film of moisture, it allows nematodes to move upwards to new leaves and stems. They enter through stomata or wounds. The nematodes feed on the parenchymatous cells of the cortex once inside the plant. They release an enzyme pectinase that dissolves the cell walls. Once the nematodes begin to feed on the plant, cells near the head of the nematodes lose all or a portion of their contents. The cells surrounding these begin to divide and enlarge. This develops into a gall or malformation of the seedling. This opening allows secondary pathogens to enter such as bacteria and fungi to enter. Favorable entry of young seedlings in the soil occurs through root cap or from inside the seed. The plant cells become enlarged due to the disappearance of chloroplasts and an increase of intercellular spaces in parenchyma tissue. Once the bulbs enlarge, the nematodes will migrate down the stem. This causes the stem to become puffy and soft due to cavities, which can lead to collapse. The nematodes will only enter the soil again if living conditions become unfavorable.

Distribution and Environment
This nematode is found in most temperate areas of the world including Europe and the Mediterranean region, North and South America, northern and southern Africa, Asia and Oceania, but is not usually found in tropical regions. The suitable environment for these nematodes is between 15-20°C and they require adequate moisture to move.

Morphology and biology
These nematodes are microscopic worms approximately 1.5 millimetres long. They penetrate into plants from either the soil or infested planting material and occasionally from seeds. They live between the cells of onion or garlic leaves and between the scales of the bulbs where they feed on cell sap and multiply. The female lays 250 eggs during a season and six generations may develop under optimum conditions when the temperature is in the range 15-20°C. As the number of nematodes increase, visual signs begin to occur. Onion leaves start to curl, garlic leaves become yellow and die, bulb scales are loosened and bulb necks become cracked. Development continues in infested bulbs during storage. This nematode is not restricted to onions and garlic. Its other plant hosts include peas, beetroot, vegetable marrow, pumpkin, rhubarb, and ornamental bulbs. Some weeds also act as hosts including Stellaria media, Linaria vulgaris, Polygonum aviculare, Fallopia convolvulus and Galium aparine.

Management
Several different methods are currently employed to reduce the presence and destruction of bulb and stem nematodes. Infection can be prevented by insuring that only clean seeds and bulbs are planted. Seeds and bulbs should be inspected for any signs of disease and rot before planting. Do not plant any that show signs of disease. When importing seeds or bulbs from other areas, ensure that the source is not infected with nematodes and the stock is clean. Bulbs and sets can be disinfected by hot water treatments. Soaking them in 110 to 115 degree Fahrenheit water with formalin, a formaldehyde solution, for two to three hours can successfully kill nematodes. Proper sanitation in fields and of tools is essential to preventing and controlling the spread of stem and bulb nematodes. Nematodes survive and reproduce in infected plants and residues. The fourth stage juvenile is the most resilient and can survive repeated desiccation or drying and recover upon rehydration. All infected tissues should be removed from growing sites and destroyed to control populations. To reduce the spread of nematodes, all farm tools and equipment should be cleaned of potentially contaminated soil before moving them to a new location. These nematodes are highly host specific so switching crops in three year rotations deprives them of a suitable host and starves the population. Because some weeds serve as hosts for nematodes, controlling weeds in fields decreases the number of susceptible hosts and the ability of the nematodes to survive and spread. The time a susceptible host crop is planted also infects the severity of nematode damage. Cooler temperatures and lower humidity can suppress the reproduction and infestation rates of nematodes.  Greco, Nicola. Epidemiology and Management of Ditylenchus Dipsaci on Vegetable Crops in Southern Italy. Institute of Nematologia Agraria, Bari, Italy. Nematropica 23:247-251. 1993. Avoid planting susceptible bulbs, seeds or seedling during seasons of peak nematode infection. Fumigation of soil in fields in the fall can control nematodes on a susceptible crop in the spring. A nematicide fumigant that is specific to the Ditylenchus species should be used. Selectively fumigate only the regions of the fields that are infected to ensure that the high cost of fumigating does not mitigate the economic gain from saving crops from nematode damage. Fumigants are usually applied before planting and subsequently after emergence.

Importance
Nearly 450 different plant species are susceptible to Ditylenchus dipsaci due to the vast number of races. Many of these plants are economically valuable food crops and ornamentals that cannot be sold if they are infected or damaged by stem and bulb nematodes. Due to the severity of the damage it causes, Ditylenchus destructor is one of the five nematodes listed on the European and Mediterranean Plant Protection Organization (EPPO) quarantine list to protect countries from the introduction and spread of harmful plant pathogens. These nematodes are especially important economically because they damage they cause renders the plants unmarketable. Crops such as onions and carrots cannot be sold because the vegetable product itself is infected and damaged. Other crops such as alfalfa, oats and tulips may not be sold for their roots, but the nematodes also cause necrosis and stunting that slowly destroy the plant. Seeds, bulbs or saplings infected with nematodes often do not survive to maturity and yield no economic potential.

Importance
Nearly 450 different plant species are susceptible to Ditylenchus dipsaci due to the vast number of races. Many of these plants are economically valuable food crops and ornamentals that cannot be sold if they are infected or damaged by stem and bulb nematodes. Due to the severity of the damage it causes, Ditylenchus destructor is one of the five nematodes listed on the European and Mediterranean Plant Protection Organization (EPPO) quarantine list to protect countries from the introduction and spread of harmful plant pathogens. These nematodes are especially important economically because they damage they cause renders the plants unmarketable. Crops such as onions and carrots cannot be sold because the vegetable product itself is infected and damaged. Other crops such as alfalfa, oats and tulips may not be sold for their roots, but the nematodes also cause necrosis and stunting that slowly destroy the plant. Seeds, bulbs or saplings infected with nematodes often do not survive to maturity and yield no economic potential.

Welcome!
Hello, SarahNicoleTaylor-3, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful: I hope you enjoy editing here and being a Wikipedian! Please sign your messages on talk pages using four tildes ( ~ ); this will automatically insert your username and the date. If you need help, check out Questions, ask me on my talk page, or ask your question on this page and then place  before the question. Again, welcome! Nathan Johnson (talk) 20:48, 27 October 2012 (UTC)
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