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.

There is no resistance to Citrus Black Spot and once a tree has been infected there is no known cure causing tree removal to be the best option. Both Federal and State governments have recommended the following preventative measures.

To control "Guignardia citriparpa" fungicides like copper and/or strobilurins should be applied monthly from early May to the middle of September (in the northern hemisphere). Applications of the fungicides are recommended in early April (northern hemisphere) if that month has experienced more rainfall than usual resulting in the ideal conditions for citrus black spot to form.

Table 1. Recommended Chemical Controls for Citrus Black Spot

1)Lower rates can be used on smaller trees. Do not use less than minimum label rate.

2)Mode of action class for citrus pesticides from the Fungicide Resistance Action Committee (FRAC) 20111. Refer to ENY-624, "Pesticide Resistance and Resistance Management," in the 2012 Florida Citrus Pest Management Guide for more details.

3)Do not use more than 4 applications of strobilurin fungicides/season. Do not make more than 2 sequential applications of strobilurin fungicides.

Another method of control is to accelerate the leaf litter decomposition under the trees in citrus groves. Accelerating this decomposition reduces the chance for ascospore inoculation which generally takes place in the middle of March. There are three possible methods to hasten this decomposition. One method is the increase the mircrosprinkler irrigation in the grove to half an hour for at least five days of the week. This form of control should continue for about a month and a half. The second method is to apply urea or ammonium to the leaf litter. The last and final method to accelerate leaf decomposition is to apply lime or calcium carbonate to the litter. Urea, lime, and calcium carbonate reduce the number of fungal structures and spore production. Since the fungus requires wet conditions to thrive, air flow in the citrus grove should be maximized to reduce leaf wetness.

Along with these methods it is also important to get rid of debris such as fallen fruit or twigs in a manner that reduces the chances of infecting other plants. Citrus Black Spot can colonize and reproduce on dead twigs. To dispose of citrus debris it should either be heated to a minimum of 180℉ for two hours, incinerated, buried in a landfill, or fed to livestock. Plant trash should be moved with caution if at all to avoid spreading the infectious ascospores. Any trees that are infected with citrus black spot should be removed from the grove and disposed of. These trees must be removed because those that are declining and stressed will often have off season bloom. If there is more than one age of fruit present on the tree, it is possible for the asexual spores on the fruit to be transferred to new fruit, intensifying the disease. This off season blooming is often more problematic with Valencia oranges when old and new crops overlap.

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.

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.

The amount of initial inoculum will be reduced when a crop other than corn is planted for ≥2 years in that given area; meanwhile proper tillage methods are carried out. Clean plowing and 1-year crop rotation in the absence of corn allows for greater reductions of the disease as well. Note that conventional tilling can reduce disease but can lead to greater soil erosion.

Thousand cankers disease can be spread by moving infected black walnut wood. Trees intended for shipment should be inspected for dieback and cankers and galleries after harvest. G. morbidia or the walnut twig beetle ("Pityophthorus juglandis") are not currently known to be moved with walnut seed . There is currently no chemical therapy or prevention available for the disease making it difficult to control the spread of the disease from the west to the eastern united states. Wood from infected trees can still be used for commercial value, but safety measures such as removing the bark, phloem, and cambium to reduce the risk of spreading the disease with shipment. Quarantines have been put in place in some states to reduce the potential movement of fungus or beetle from that region. On May 17th, 2010, the Director of the Michigan Department of Agriculture issued a quarantine from affected states to protect Michigan’s black walnut ecology and production. Contacting the appropriate entities about possible infections is important to stopping or slowing the spread of thousand cankers disease.

The most proficient and economical method to reduce yield losses from corn grey leaf spot is by introducing resistant plant varieties. In places where leaf spot occur, these crops can ultimately grow and still be resistant to the disease. Although the disease is not completely eliminated and resistant varieties show disease symptoms, at the end of the growing season, the disease is not as effective in reducing crop yield. SC 407 have been proven to be common corn variety that are resistant to grey leaf spot. If grey leaf spot infection is high, this variety may require fungicide application to achieve full potential. Susceptible varieties should not be planted in previously infected areas (see high risk table).

In a September 2008 study, a possible fungicide was tested. The abstract of the study reads as follows:

In this study, the systemic fungicide propiconazole completely inhibited mycelial growth of Raffaelea spp. in vitro at concentrations 0.1 parts per million (ppm) or greater and was fungitoxic at 1 ppm or greater, whereas the fungicide thiabendazole was less inhibitory. None of the ten mature redbay trees that received root-flare injections of propiconazole developed crown wilt symptoms for at least 30 weeks after being inoculated with Raffaelea spp., whereas nine of ten untreated control trees wilted in more than one-third of their crowns. Propiconazole was retained in the stem xylem for at least 7.5 months after injection but was more frequently detected in samples from trees injected 4.5 months earlier and was not well detected in small-diameter branches. Results suggest that propiconazole may be useful in preventing laurel wilt in redbay, but limitations and questions regarding duration of efficacy, rate of uptake, and efficacy under different levels of disease pressure remain.

In 2011, the EPA granted a Section 18 Emergency Exemption allowing the use of Tilt (a formulation of propiconazole) on commercial avocado trees to prevent laurel wilt disease. However, questions remain about the efficacy and cost-effectiveness of this treatment in commercial groves

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.

Some redbay trees may be resistant to the disease, and future research will investigate factors associated with resistance, in the hope that tolerant varieties can be identified and developed.

The genus Geosmithia (Ascomycota: Hypocreales) are generally saprophytic fungi affecting hardwoods. As of its identification in 2010, the species G. morbida is the first documented as a plant pathogen. The walnut twig beetle ("Pityophthorus juglandis") carries the mycelium and conidia of the fungus as it burrows into the tree. The beetle is currently only found in warmer climates, allowing for transmission of the fungus throughout the year. Generations of the beetle move to and from black walnut trees carrying the fungus as they create galleries, the adults typically moving horizontally, and the larvae moving vertically with the grain. As they move through the wood, the beetles deposit the fungus, which is then introduced into the phloem; cankers then develop around the galleries, quickly girdling the tree. The fungus has not been found to provide any value to the beetle. A study done by Montecchio and Faccoli in Italy in 2014 found that no fungal fruiting bodies were found around or on the cankers but in the galleries. Mycelium, and sometimes conidiophores and conidia were observed in the galleries as well. No sexual stage of the fungus has currently been found.

Citrus Black Spot is a fungal disease caused by Guignardia citricarpa. This Ascomycete fungus affects citrus plants throughout subtropical climates, causing a reduction in both fruit quantity and quality. Symptoms include both fruit and leaf lesions, the latter being critical to inter-tree dispersal. Strict regulation and management is necessary to control this disease since there are currently no citrus varieties that are resistant.

Apple scab is a disease of "Malus" trees, such as apple trees, caused by the ascomycete fungus "Venturia inaequalis". The disease manifests as dull black or grey-brown lesions on the surface of tree leaves, buds or fruits. Lesions may also appear less frequently on the woody tissues of the tree. Fruits and the undersides of leaves are especially susceptible. The disease rarely kills its host, but can significantly reduce fruit yields and fruit quality. Affected fruits are less marketable due to the presence of the black fungal lesions.

Common spot of strawberry is one of the most common and widespread diseases of strawberry. Common spot of strawberry is caused by the fungus Mycosphaerella fragariae (imperfect stage is "Ramularia tulasnei"). Symptoms of this disease first appear as circular, dark purple spots on the leaf surface. "Mycosphaerella fragariae" is very host specific and only infects strawberry.

Mycosphaerella fragariae is a species from family Mycosphaerellaceae.

Necrotic ring spot is a common disease of turf caused by soil borne fungi (Ophiosphaerella korrae) that mainly infects roots (4). It is an important disease as it destroys the appearance of turfgrasses on park, playing fields and golf courses. Necrotic Ring Spot is caused by a fungal pathogen that is an ascomycete that produces ascospores in an ascocarp (6). They survive over winter, or any unfavorable condition as sclerotia. Most infection occurs in spring and fall when the temperature is about 13 to 28°C (5). The primary hosts of this disease are cool-season grasses such as Kentucky bluegrass and annual bluegrass (6). Once turf is infected with "O. korrae", it kills turf roots and crowns. Symptoms of the disease are quite noticeable since they appear as large yellow ring-shaped patches of dead turf. Management of the disease is often uneasy and requires application of multiple controls. The disease can be controlled by many different kind of controls including chemicals and cultural.

In affected orchards, new infections can be reduced by removing leaf litter and trimmings containing infected tissue from the orchard and incinerating them. This will reduce the amount of new ascospores released in the spring. Additionally, scab lesions on woody tissue can be excised from the tree if possible and similarly destroyed.

Chemical controls can include a variety of compounds. Benzimidazole fungicides, e.g., Benlate (now banned in many countries due to its containing the harmful chemical benzene) work well but resistance can arise quickly. A number of other chemical classes including sterol inhibitors such as Nova 40, and strobilurins such as Sovran are used extensively; however, some of these are slowly being phased out because of resistance problems.

Contact fungicides not prone to resistance, such as Captan, are viable choices. Potassium bicarbonate is an effective fungicide against apple scab, as well as powdery mildew, and is allowed for use in organic farming. Copper and Bordeaux mixture are traditional controls but are less effective than chemical fungicides, and can cause russeting of the fruit. Wettable sulfur also provides some control. Timing of application and concentration varies between compounds.

An apple scab prognostic model called RIMpro was developed by Marc Trapman, which numerically grades infection risk and can serve as a warning system. It allows better targeted spraying. Parameter for calculation are wetness of leaves, amount of rain fall and temperature.

Fifteen genes have been found in apple cultivars that confer resistance against apple scab. Researchers hope to use cisgenic techniques to introduce these genes into commercial cultivars and therefore create new resistant cultivars. This can be done through conventional breeding but would take over 50 years to achieve.

Black pod disease is caused by many different "Phytophthora spp." pathogens all expressing the same symptoms in cocoa trees ("Theobroma cacao"). This pathogen if left untreated can destroy all yields; annually the pathogen can cause a yield loss of up to 1/3 and up to 10% of total trees can be lost completely. With the value of the cocoa industry throughout the world being so large there are much research and control efforts that go into these "Phytophthora spp." pathogens.

This pathogen can be located anywhere on the cocoa trees but is most noted for the black mummified look it will give to the fruit of the cocoa tree. Staying ahead of the pathogen is the best means of control, the pathogen can be greatly reduced if leaf litter is not allowed to stay on the ground and if the pathogen gets out of hand chemical control can be used. This pathogen is mostly found in tropical areas where the cocoa trees are located and need rainfall in order to spread its spores.

Raspberry Leaf Spot is a plant disease caused by Sphaerulina rubi, an ascomycete fungus. Early symptoms of infection are dark green spots on young leaves. As the disease progresses, these spots turn tan or gray in color. Disease management strategies for Raspberry Leaf Spot include the use of genetically resistant raspberry plant varieties and chemical fungicide sprays.

Raspberries are an important fruit, mainly grown in Washington, Oregon and California. Although they are also grown in the Midwest and northeastern states, the output is not nearly as great due to the colder weathers and shorter growing seasons. "S. rubi" prefers warmer and wetter conditions, which can make raspberry production very difficult in California.

Ascochyta blights occur throughout the world and can be of significant economic importance. Three fungi contribute to the ascochyta blight disease complex of pea ("Pisum sativum"). "Ascochyta pinodes" (sexual stage: "Mycosphaerella pinodes") causes Mycosphaerella blight. "Ascochyta pinodella" (synonym: "Phoma medicaginis" var. "pinodella") causes Ascochyta foot rot, and "Ascochyta pisi" causes Ascochyta blight and pod spot. Of the three fungi, "Ascochyta pinodes" is of the most importance. These diseases are conducive under wet and humid conditions and can cause a yield loss of up to fifty percent if left uncontrolled. The best method to control ascochyta blights of pea is to reduce the amount of primary inoculum through sanitation, crop-rotation, and altering the sowing date. Other methods—chemical control, biological control, and development of resistant varieties—may also be used to effectively control ascochyta diseases.

Velvet Blight is a disease that affects the stems, branches, leaves, fruits or trunks of plants and trees. This disease is primarily caused by three fungal species from the genus "Septobasidium": "S. bogoriense", "S. pilosum" and "S. theae".

It is known to affect mainly tea plants ("Thea" genus).

The most studied of these species is "S. bogoriense", most notably due to the work of Ernst Albert Gäumann. "S. bogoriense" is named after the Herbarium Bogoriense (Bogor, West Java, Indonesia) which is the place where it was first identified on the bark of an unspecified tree and named by E. Nyman on June 3, 1898. This species was also listed in Otto Warburg's Monsunia in 1900.

Several decades of research in several countries with many cultivars showed that moderate levels of bitter pit could be controlled with the spraying of the trees with calcium chloride or calcium nitrate during the growing season. However, in the southern hemisphere where highly susceptible fruit had to be harvested early for export to Europe, the problem remained. An attempt to increase the calcium content by applying calcium after harvest had resulted in severe injury to the fruit. Export of susceptible apples from New Zealand was under threat and new methods for controlling bitter pit were investigated. While it was shown that bitter pit was reduced as calcium levels rose, it was not possible to determine a minimum level of calcium that would ensure that the disorder was controlled. The most effective treatment found for closed calyx fruit was to submerge the fruit in the calcium chloride solution and to apply a vacuum and immediately rinsing in water. This overcame the injury problem and gave much better control of the disorder. The vacuum treatment was commercialized in New Zealand for the Cox's Orange Pippin cultivar in 1978 and was used for several years. However the treatment was expensive and could not be used for open calyx cultivars.

A simpler treatment was developed in Western Australia and was adopted in Australia and in New Zealand. This involved dipping the fruit in the calcium solution and rinsing in water after about 36 hours. This treatment has been confirmed by independent workers and has generally been adopted in Australia and New Zealand. Postharvest dipping in a calcium solution has been recommended in some other countries where bitter pit is severe. However the problem of fruit injury does not seem to have been addressed.

It appears that bitter pit can generally be reduced by using good horticultural practices. Usually spraying throughout the growing season with a calcium salt is also necessary for moderately susceptible cultivars. It is more difficult to control storage pit in highly susceptible cultivars as field spraying may not be able to apply sufficient calcium to the fruit. Improved control can be obtained by also dipping the fruit in a 2-3 per cent calcium chloride solution after harvest and rinsing the fruit in water after about 36 hours.

This disease is mainly found in tropical climates in Southern Asia, however some scattering exists:

To reduce the itching, an application of anti-itch cream containing hydrocortisone, calamine, or benzyl benzoate is often used (though calamine has been shown not to be effective). Hydrogen peroxide and capsaicin cream has also been effective. Another good way to relieve itching is to apply heat—either by using a hand held shower with water hot as one can stand, or by heating the bite with a hair dryer. The heat method will relieve itching for about four hours and will require repeating.

In some cases, the chigger is still present when the bite appears. A 10× magnifier can be used to see the chigger and it may be removed with fine-tipped tweezers. Once it is gone, covering the bite with nail polish, calamine lotion, vaseline or other petroleum jelly, baby oil, or anything else may help the pain and itching, but will neither suffocate the chigger nor help the bites heal any faster. Medication such as antihistamines or corticosteroid creams may be prescribed by doctors, and might help in some instances.

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.

A definitive diagnosis of health effects due to bed bugs requires a search for and finding of the insect in the sleeping environment as symptoms are not sufficiently specific. Other possible conditions with which these conditions can be confused include scabies, allergic reactions, mosquito bites, spider bites, chicken pox and bacterial skin infections. Bed bugs classically form a line of bites colloquially referred to as "breakfast, lunch, and dinner" and rarely feed in the armpit or behind the knee which may help differentiate it from other biting insects. If the number in a house is large a pungent sweet odor may be described.