Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
Fertilisers like ammonium phosphate, calcium ammonium nitrate, urea can be supplied. Foliar spray of urea can be a quick method.
Diagnosis of clinical poisoning is generally made by documenting exposure, identifying the neurologic signs, and analyzing serum for alpha-mannosidase activity and swainsonine.
In mule deer, clinical signs of locoism are similar to chronic wasting disease. Histological signs of vacuolation provide a differential diagnosis.
Sub-clinical intoxication has been investigated in cattle grazing on "Astragalus mollissimus". As the estimated intake of swainsonine increased, blood serum alpha-mannosidase activity and albumin decreased, and alkaline phosphatase and thyroid hormone increased.
The visual symptoms of nitrogen deficiency mean that it can be relatively easy to detect in some plant species. Symptoms include poor plant growth, and leaves that are pale green or yellow because they are unable to make sufficient chlorophyll. Leaves in this state are said to be chlorotic. Lower leaves (older leaves) show symptoms first, since the plant will move nitrogen from older tissues to more important younger ones. Nevertheless, plants are reported to show nitrogen deficiency symptoms at different parts. For example, Nitrogen deficiency of tea is identified by retarded shoot growth and yellowing of younger leaves.
However, these physical symptoms can also be caused by numerous other stresses, such as deficiencies in other nutrients, toxicity, herbicide injury, disease, insect damage or environmental conditions. Therefore, nitrogen deficiency is most reliably detected by conducting quantitative tests in addition to assessing the plants visual symptoms. These tests include soil tests and plant tissue test.
Plant tissue tests destructively sample the plant of interest. However, nitrogen deficiency can also be detected non-destructively by measuring chlorophyll content.
Chlorophyll content tests work because leaf nitrogen content and chlorophyll concentration are closely linked, which would be expected since the majority of leaf nitrogen is contained in chlorophyll molecules. Chlorophyll content can be detected with a Chlorophyll content meter; a portable instrument that measures the greenness of leaves to estimate their relative chlorophyll concentration.
Chlorophyll content can also be assessed with a chlorophyll fluorometer, which measures a chlorophyll fluorescence ratio to identify phenolic compounds that are produced in higher quantities when nitrogen is limited. These instruments can therefore be used to non-destructively test for nitrogen deficiency.
The most widely used potassium fertilizer is potassium chloride (muriate of potash). Other inorganic potassium fertilizers include potassium nitrate, potassium sulfate, and monopotassium phosphate. Potassium-rich treatments suitable for organic farming include feeding with home-made comfrey liquid, adding seaweed meal, composted bracken, and compost rich in decayed banana peels. Wood ash also has high potassium content. Adequate moisture is necessary for effective potassium uptake; low soil water reduces K uptake by plant roots. Liming acidic soils can increase potassium retention in some soils by reducing leaching; practices that increase soil organic matter can also increase potassium retention.
Calcium deficiency can sometimes be rectified by adding agricultural lime to acid soils, aiming at a pH of 6.5, unless the subject plants specifically prefer acidic soil. Organic matter should be added to the soil to improve its moisture-retaining capacity. However, because of the nature of the disorder (i.e. poor transport of calcium to low transpiring tissues), the problem cannot generally be cured by the addition of calcium to the roots. In some species, the problem can be reduced by prophylactic spraying with calcium chloride of tissues at risk.
Plant damage is difficult to reverse, so corrective action should be taken immediately, supplemental applications of calcium nitrate at 200 ppm nitrogen, for example. Soil pH should be tested, and corrected if needed, because calcium deficiency is often associated with low pH.
Early fruit will generally have the worst systems, with them typically lessening as the season progresses. Preventative measures, such as irrigating prior to especially high temperatures and stable irrigation will minimize the occurrence.
Detecting phosphorus deficiency can take multiple forms. A preliminary detection method is a visual inspection of plants. Darker green leaves and purplish or red pigment can indicate a deficiency in phosphorus. This method however can be an unclear diagnosis because other plant environment factors can result in similar discoloration symptoms. In commercial or well monitored settings for plants, phosphorus deficiency is diagnosed by scientific testing. Additionally, discoloration in plant leaves only occurs under fairly severe phosphorus deficiency so it is beneficial to planters and farmers to scientifically check phosphorus levels before discoloration occurs. The most prominent method of checking phosphorus levels is by soil testing. The major soil testing methods are Bray 1-P, Mehlich 3, and Olsen methods. Each of these methods are viable but each method has tendencies to be more accurate in known geographical areas. These tests use chemical solutions to extract phosphorus from the soil. The extract must then be analyzed to determine the concentration of the phosphorus. Colorimetry is used to determine this concentration. With the addition of the phosphorus extract into a colorimeter, there is visual color change of the solution and the degree to this color change is an indicator of phosphorus concentration. To apply this testing method on phosphorus deficiency, the measured phosphorus concentration must be compared to known values. Most plants have established and thoroughly tested optimal soil conditions. If the concentration of phosphorus measured from the colorimeter test is significantly lower than the plant’s optimal soil levels, then it is likely the plant is phosphorus deficient. The soil testing with colorimetric analysis, while widely used, can be subject to diagnostic problems as a result of interference from other present compounds and elements. Additional phosphorus detection methods such as spectral radiance and inductively coupled plasma spectrometry (ICP) are also implemented with the goal of improving reading accuracy. According to the World Congress of Soil Scientists, the advantages of these light-based measurement methods are their quickness of evaluation, simultaneous measurements of plant nutrients, and their non-destructive testing nature. Although these methods have experimental based evidence, unanimous approval of the methods has not yet been achieved.
Physiological plant disorders are caused by non-pathological conditions such as poor light, adverse weather, water-logging, phytotoxic compounds or a lack of nutrients, and affect the functioning of the plant system. Physiological disorders are distinguished from plant diseases caused by pathogens, such as a virus or fungus. While the symptoms of physiological disorders may appear disease-like, they can usually be prevented by altering environmental conditions. However, once a plant shows symptoms of a physiological disorder it is likely that that season’s growth or yield will be reduced.
Boric acid (16.5%boron), borax (11.3% boron) or SoluBor (20.5% boron) can be applied to soils to correct boron deficiency. Typical applications of actual boron are about 1.1 kg/hectare or 1.0 lb/acre but optimum levels of boron vary with plant type. Borax, Boric Acid or Solubor can be dissolved in water and sprayed or applied to soil as a dust. Excess boron is toxic to plants so care must be taken to ensure correct application rate and even coverage. Leaves of many plants are damaged by boron; therefore, when in doubt, only apply to soil. Application of boron may not correct boron deficiency in alkaline soils because even with the addition of boron, it may remain unavailable for plant absorption. Continued application of boron may be necessary in soils that are susceptible to leaching such as sandy soils. Flushing soils containing toxic levels of boron with water can remove the boron through leaching.
This disease is hard to control because plants can carry the pathogen prior to showing any symptoms. It is important to be aware of where new plants are being planted so that they aren't exposed to disease.
The most effective method to avoid disease is to plant resistant cultivars that are specific to the location of planting. Some examples of resistant cultivars include Allstar, Cardinal, Delite, Honeoye, Jewel and Tennessee Beauty. Examples of susceptible cultivars that should be avoided include Sparkle, Sunrise, Raritan and Catskill.
Amongst the many different management strategies, cultural control practices play a significant role in prevention or reduction of disease. Some common cultural practices that have been used are as follows. In order to have more successful yields, strawberry plants should be planted in well-drained soil, in an area exposed to lots of available sunlight and air circulation. Presence of weeds may reduce air circulation for strawberry plants and create a shaded, moist environment, which would make the plants more wet and susceptible to disease. Therefore, weed growth needs to be prevented, either by chemical or cultural control methods. Immediately after harvest, any severely infected plants and plant debris should be raked, removed and burned completely to get rid of any remaining spores and reduce inoculum of the pathogen.
At the beginning of renovation, which occurs after harvest, one application of nitrogen fertilizers should be applied to help with canopy regrowth. About 4–6 weeks later, it is generally a good time to apply another application of nitrogen fertilization to the developing strawberry plants. This will allow for the plants to absorb nutrients provided by the fertilizer. However, applying too much nitrogen fertilizer throughout the spring, may result in an abundance of young foliage tissues that could be susceptible to disease.
Fungicides are not necessarily required, however if the strawberry grower decides to use fungicides, they should be applied during early in the spring and immediately after renovation. A fungicide spray schedule may also be put into place. It is recommended to spray in intervals of about 2 weeks. Examples of some recommended fungicides are Bulletin 506-B2, Midwest Commercial Small Fruit and Grape Spray Guide for commercial growers and Bulletin 780, Controlling Disease and Insects in Home Fruit Plantings for backyard home growers.
Because "O. sericea" is both frequently encountered and relatively palatable to livestock, it is an important cause of economic losses in livestock production. Keeping livestock away from locoweed infested pasture in spring and fall when grass and other forbs are not actively growing is recommended. Another suggested remedy is to provide palatable supplemental nutrients if animals are to be kept in infested pasture. These remedies take into account livestock preference for locoweed during seasons when grass is dry and not very nutritious. Conditioned food aversion has been used experimentally to discourage livestock from eating it. In horses, a small study has shown promising results using lithium chloride as the aversive agent.
Genetic resistance is the preferred disease management strategy because it allows farmers to minimize chemical intervention. Less pesticide and fungicide can encourage biological control agents, reduce production costs, and minimize the chemical residues in fruit. Some genetic varieties of raspberry are better than others for the control of leaf spot. Nova and Jewel Black are both resistant varieties, while Prelude and Honey Queen Golden Raspberry have some resistance, but can be susceptible depending on environmental conditions. Reiville, Canby, Encore and Anne are the most susceptible varieties.
Cultural practices are also important for the management of Raspberry Leaf Spot. Sanitation, which includes the removal of all plant debris and infected canes in the fall, reduces places for the pathogen to overwinter. Pruning the raspberry plants and planting in rows will allow for airflow to dry leaves, creating an uninviting environment for fungi. Furthermore, air flow circulation is important for reducing sporulation and successful infection. Lastly, avoid wounding the plants, as this may provide the fungus with an opportunity to infect.
Necrotic ring spot can be managed through chemical and cultural controls. Cultural control includes the use of ammonium sulfate or other acidifying fertilizers to suppress the pathogen by lowering the pH of the soil to between 6.0 and 6.2. The more acidic soil discourages the activity of "O. korrae" (9) When reducing pH to these levels, additional manganese applications should be undertaken to compensate for lower pH. As of now, there are only two resistant cultivars of bluegrass, which are ‘Riviera’, and ‘Patriot’ (9). One component of their resistance could be that they are tolerant to low temperature, because the grass is more susceptible to the pathogen under colder temperatures(8). In addition, reducing watering inputs and growing turf on well drained soils can lessen disease symptoms.
Many different fungicides are used to control the pathogen, Fenarimol, Propiconazole, Myclobutanil, and Azoxystrobin (8). Historically, Fenarimol and Myclobutanil were predominantly used (14). In a study where diluted pesticides were sprayed throughout infested test plots, Fenarimol was found to be the most effective with a 94.6% reduction of the disease. Myclobutanil also decreased the amount of disease, but only by 37.7% (8). Myclobutanil is generally recognized as a very weakly acting demethylation inhibitor (DMI) fungicide and fenarimol is no longer registered for turf so a number of other DMI fungicides have been employed successfully, including Propiconazole, Tebuconazole, Metconazole and others. Pyraclostrobin and Fluoxastrobin have also been used to control the pathogen.
Manganese deficiency is easy to cure and homeowners have several options when treating these symptoms. The first is to adjust the soil pH. Two materials commonly used for lowering the soil pH are aluminum sulfate and sulfur. Aluminum sulfate will change the soil pH instantly because the aluminum produces the acidity as soon as it dissolves in the soil. Sulfur, however, requires some time for the conversion to sulfuric acid with the aid of soil bacteria. If the soil pH is not a problem and there is no manganese actually in the soil then Foliar feeding for small plants and medicaps for large trees are both common ways for homeowners to get manganese into the plant.
There are a number of control methods to prevent and reduce the Banana Freckle disease. The paper bag method seems to be the most effective way to gain physical control of the pathogen. The infected leaves are the primary source of spores, and placing a bag over the bananas, once harvested, creates a barrier to prevent inoculum from spreading to the fruit.
Some cultural controls include pruning out infectious plant material, planting in pathogen-free fields, and practicing proper sanitation techniques. In the Philippines, pruning and cutting out patches of infected tissue have prevented the spread of the pathogen in the plant during disease outbreaks. General sanitation practices have also reduced the spread of inoculum. When planters failed to maintain sanitary equipment, seeds, and soil, they witnessed severe fruit infections. The more freckles seen on the leaves of the plant, the more the fruit develops symptoms of the disease. Inversely, less freckles corresponded to less disease.
In addition, multiple fungicides have been seen to reduce Banana Freckle disease. In Hawaii, spraying the leaves and fruit with maneb (1 lb./100 gal water plus 4 oz of sticker-spreader) every 2 weeks or once a month throughout the year has remarkably reduced the spread of inoculum. In Taiwan, spraying fungicides, such as phaltan, orthocide, chlorothalonil, dithiocarbamates, and propiconazole, biweekly have produced effective results against the disease. In the Philippines, chemical controls used against Black or Yellow Sigatoka disease have been helpful. These consist of mancozeb, triazoles, tridemorph, and strobilurin. Mancozeb seems to be the most effective fungicide against Banana Freckle disease in Hawaii and the Philippines . These fungicides do not eliminate the pathogen completely, but they reduce the inoculum levels and eventually reduce yield loss.
Lastly, eradication of infected plants can prevent further infection of other fruit around the area.
There are very few things that can be done to control the spread of bacterial soft rots, and the most effective of them have to do with simply keeping sanitary growing practices.
Storage warehouses should be removed of all plant debris, and the walls and floors disinfected with either formaldehyde or copper sulfate between harvests. Injury to plant tissues should be avoided as much as possible, and the humidity and temperature of the storage facility should be kept low using an adequate ventilation system. These procedures have proven themselves to be very effective in the control of storage soft rot of potato in Wisconsin.
It also helps if plants are planted in well-drained soils, at intervals appropriate for adequate ventilation between plants. Few varieties are resistant to the disease and none are immune, so rotating susceptible plants with non-susceptible ones like cereals is a practice positive to limiting soft rot infection.
The control of specific insect vectors is also a good way of controlling disease spread in the field and in storage. Soil and foliage insecticide treatment helps controls the bugs that frequently cause wounds and disseminate the bacteria.
There are several ways to manage turf melting out. They include both cultural and chemical.
The first strategy of management is the cultural practices for reducing the disease. It includes adequating row and plant spacing that promote better air circulation through the canopy reducing the humidity; preventing excessive nitrogen on fertilization since nitrogen out of balance enhances foliage disease development; keeping the relatively humidity below 85% (suitable on greenhouse), promote air circulation inside the greenhouse, early planting might to reduce the disease severity and seed treatment with hot water (25 minutes at 122 °F or 50 °C).
The best way to manage SDS is with a resistant variety. One issue is that most resistant varieties are only partially resistant so yield reductions may still occur. Another issue is that the plant needs resistance for SDS and SCN in order to gain true resistance because of their synergistic relationship and most varieties do not have resistance for both. Aside from resistance, the only other ways to control SDS are management practices.
These include:
- Avoid planting in cool, wet conditions
- Plant later when the soil has warmed up
- Try avoiding soil compaction as it creates wet spots in the soil that can increase plant stress and SDS infection rates
- Managing for SCN as this nematode often occurs alongside "F. virguliforme"
- Deep tillage to break up compaction and help the soil warm faster
One common management tactic used in other pathogen management plans is crop rotation. In some cases, disease severity can be reduced but most often it is not effective. This is because of chlamydospores and macroconidia as they can persist in soils for many years.
Fungicides are another common product used to control fungal pathogens. In-furrow applications and seed treatments with fungicides have some effect in decreasing disease instance but in most cases, the timing isn't right and the pathogen can still infect the plants. Foliar applications of fungicides have no effect on disease suppression for SDS because the fungi are found in the soil and mainly the roots of the plants. Most foliar fungicides do not move downward through plants, therefore having no effect on the pathogen.
Bacterial leaf streak of wheat is not easily prevented, but can be controlled with clean seed and resistance. Some foliar products, such as pesticides and antibiotic compounds, have been tested for effectiveness, but have proven to have insignificant outcomes on the bacterial pathogen.
Using clean seed, with little infection, has yielded effective results for researchers and producers. The pathogen, being seed-borne, can be controlled with the elimination of contaminated seed, however, clean seed is not always a sure solution. Because the pathogen may still live in the soil, the use of clean seed is only effective if both the soil and seed are free of the pathogen. Currently, there are no successful seed treatments available for producers to apply to wheat seed for the pathogen.
Variety resistance is another option for control of the disease. Using cultivars such as Blade, Cromwell, Faller, Howard or Knudson, which are resistant to BLS may reduce the impact of the disease and potentially break the disease cycle. Avoiding susceptible cultivars such as Hat Trick, Kelby, and Samson may also reduce the presence of the disease and reduce the amount of bacterial residue in the soil. Using integrated pest management techniques such as tillage to turn over the soil and bury the infection as well as rotating crops may assist with disease management, but are not a definitive control methods. Depending on conditions, the bacteria may survive for up to 81 months. Because the bacteria is moisture driven, irrigation may also increase the risks of BLS infection.
The second strategy of management is the sanitization control in order to reduce the primary inoculum. Remove and destroy (burn) all plants debris after the harvest, scout for disease and rogue infected plants as soon as detected and steam sanitization the greenhouse between crops.
Certain techniques can be used to determine which pathogen is causing disease. One standard technique for distinguishing strains is microscopy. Under a microscope, "M. pinodes" can be diagnosed by the presence of pseudothecia. "P pinodella" can be diagnosed by the size of conidia produced. "P. pinodella" produces conidia that are smaller than the conidia of "M. pinodes" or "A. pisi". "A. pisi" can be diagnosed by the color of the conidia. In comparison to the light colored, buff spore masses of "M. pinodes" and "P. pinodella" produced on oatmeal agar, "A. pisi" spores masses are carrot red.
Other techniques for diagnosis involve serological assays, isoenzyme analysis, restriction fragment length polymorphisms (RFLPs), random amplified polymorphic DNA (RAPD) assays, and by using monoclonal antibodies.
Diagnosis of the cause of a physiological disorder (or disease) can be difficult, but there are many web-based guides that may assist with this. Examples are: "Abiotic plant disorders: Symptoms, signs and solutions"; "Georgia Corn Diagnostic Guide"; "Diagnosing Plant Problems" (Kentucky); and "Diagnosing Plant Problems" (Virginia).
Some general tips to diagnosing plant disorders:
- Examine where symptoms first appear on a plant—on new leaves, old leaves or all over?
- Note the pattern of any discolouration or yellowing—is it all over, between the veins or around the edges? If only the veins are yellow deficiency is probably not involved.
- Note general patterns rather than looking at individual plants—are the symptoms distributed throughout a group of plants of the same type growing together. In the case of a deficiency all of the plants should be similarly effected, although distribution will depend on past treatments applied to the soil.
- Soil analysis, such as determining pH, can help to confirm the presence of physiological disorders.
- Consider recent conditions, such as heavy rains, dry spells, frosts, etc., may also help to determine the cause of plant disorders.
Strawberry foliar nematodes are difficult to manage due to their robust life cycle. While dormant, they are quite difficult to kill, and they remain viable in dry debris for more than one year. Adult nematodes can survive desiccation and lie dormant for several years. Eggs can stay dormant until survival conditions are optimal for growth. Once eggs or nematodes are present in the soil, they are nearly impossible to eradicate because they can move laterally in the soil to escape non-optimal conditions. They are found in most foliar tissue, including the leaves, stems, buds, and crowns, making it difficult to control the disease on the plant itself once it has been infected
Many plant diseases are managed chemically, but due to a ban of nematicides there are currently no nematicides available for any type of foliar nematode. Some insecticides, pesticides, and plant product extracts from plants such as Ficus and Coffee (of which many pesticides and nematicides are neem-based ) can be used to reduce the numbers of strawberry foliar nematode (a reduction of 67-85%), but none of these chemicals can completely eradicate the nematodes once they are present in the soil. These chemicals affect all stages of the life cycle because they target the nervous system. One chemical, ZeroTol, a broad-spectrum fungicide and algaecide, was shown be to 100% potent against nematodes living in a water suspension, but the study does not show how nematodes are affected in soil or outside of a laboratory environment.
An alternative method of control is a hot water treatment, which affects all stages of the life cycle and can be used on whole plants. This treatment has been used for 60 years with some effect in greenhouse plants, but not on a widespread agricultural level. The difficulty in this treatment is that exposure times to hot water and the temperature of the water must be optimized so that the nematodes are killed, but the cultivar remains undamaged. One study, which researched five California strawberry cultivars including Chandler, Douglas, Fern, Pajaro, and Selva, demonstrated that the minimum-maximum exposure times and temperatures that killed the nematodes but did not harm the cultivars were: 20–30 minutes at 44.4⁰C, 10–15 minutes at 46.1⁰C, and 8–10 minutes at 47.7⁰. The study also found that fruit production was more sensitive to the treatment than mere survival of the plant, so the minimum exposure times are recommended when using plants for fruit production, and the maximum time is recommended when using plants for propagation.
One of the best and most practiced forms of management to reduce the local and geographical spread of the disease is sanitation. Removing the infected leaves of the plant can reduce spread in the individual plant, but because the nematode is found in most foliar tissue the nematodes may already be present in other tissues before the leaf symptoms appear. The nematodes can also move on the outside of the plant surface when water is present, so the nematodes can move around the outside surface of the plant and infect new tissues. Therefore, once plants show any signs of infection, they should be removed and destroyed. Reducing or eliminating overhead irrigation can prevent dispersal of the nematode through water splashing, and keeping the foliage dry prevents the nematodes from moving on the outside of the plant. Plants should be placed further apart to allow water to dry quickly after irrigation. In the greenhouse or nursery, soils, containers, and tools should be sterilized on a regular basis, and the floor and storage areas should be free from plant debris.
The most important form of management is prevention of introduction of the nematode to the environment. One should avoid planting infected plants, and it is recommended that new plants (especially in a personal lawn or greenhouse) be planted in an isolated area to monitor the plant for the development of symptoms before transplanting the plant near established plants. This will prevent the established plants from getting infected from a new, infected plant. All symptomatic plants should be destroyed immediately. Dead plant material should also be handled with caution. Vermiform nematodes can survive and reproduce in compost piles of dead plant material by feeding on fungi that are commonly found in compost. As a result, infected plants should be burned and sterilized to prevent the nematodes from infecting soil (which results directly from burying the material), or other plants (from allowing the plant to remain rooted in the soil near other plants as it dies).
Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils, because potassium ions (K) are highly soluble and will easily leach from soils without colloids. Potassium deficiency is also common in chalky or peaty soils with a low clay content. It is also found on heavy clays with a poor structure.
Golf courses affect the United States economy with about 18 billion dollars annually. Turf melting out is an important disease economically for golf course superintendents. When turfgrass quality is affected on a golf course, the course has a potential to lose golfers, in turn, losing money. After a golf course has an outbreak of turf melting out, the damage needs to be assessed and the turf needs to be replaced. Mending these damaged areas cost money from the fungicide applications to rid the area of the disease to the replacement of turf. Simple cultural controls help reduce the risk of this disease, but when the methods are not used, it can be costly.