The type of fungicides used to control various fungal diseases depends on the severity of the infection. Fungi cause more than 70 percent of the diseases affecting crops. Fungi are of huge economic importance in agriculture; they cause different crop diseases. Other disease-causing agents are bacteria, virus, and nematodes. Fungicide is one of the common pesticides used in agriculture.
Fungicides are types of pesticides that control fungal diseases by inhibiting or killing the fungus causing the disease. When we talk about weeds, we think of herbicides, same also for bacteria and rodents, we talk about bactericides and rodenticides respectively. Fungi are small microscopic non-green living organisms; they are highly prolific as they produce a large number of spores; this makes their dispersal very easy and very aggressive in action.
Fungi are responsible for different diseases in plants. Examples of fungal diseases are damping off of seedlings, seed decay, root rot, stem lesion, maize smut, and downy mildew to mention a few. Diseases caused by fungi are copious; this is why it is important you identify the disease affecting your plant to know the types of pesticide to use for effective action.
Why you need fungicides
I do tell farmers; do not engage in crop production parsimoniously. This is a bitter truth that most farmers do not want to believe. For you to enjoy your yield, you need to put in place every measure to avoid what will make you have a poor harvest. You should not wait for a disease symptom before you deploy preventive or control measures. the uses of fungicides are:
- To increase your yield, hence, improving the profitability of the enterprise
- To increase the storage life of the harvested crop
An attack on your crop will render these reasons irrelevant, hence you must ensure your crop is protected against any fungal diseases using the right fungicide.
Do you know…
Most fungal diseases are systemic; when your plant show a symptom, it means the disease has overcome the plant immunity, hence, the plant needs your swift response. Most fungicides need to be applied before the disease manifests or at first appearance of symptoms to enhance the effectiveness of the fungicides.
Applying fungicides cannot heal symptoms already present, even when the pathogen has been eradicated. What fungicide does is to protect new uninfected growth from that disease. What this implies is that you can actually control any fungal disease before it erupts if you include fungicide application as part of your routine managerial practices. Here, you are preventing and not controlling any fungal diseases. This is the most effective way of controlling any plant disease.
Types of Fungicides used in agriculture
There are different types of fungicides in the agro-industry today. There are organic fungicides, an example is neem oil as an organic fungicide for plants. However, for commercial purposes, chemical fungicides are commonly used. Examples of fungicide for plants are Mancozeb, Benomyl, Propiconazole, Tricyclazole, Carbendazim, Propiconazole, Metalaxyl, Difenoconazole, Hexaconazole etc.
These fungicides differ in mode of action; this is why fungicides are classified based on:
- Mode of action
- According to their activity
Types of fungicides based on their mode of action
1. Contact fungicides:
These are also called protectant. They are types of fungicides that have immediate action on the plant after application. Contact fungicides remain on the surface of the plant, waiting for an attack from any fungi; they are best used as a prophylactic measure. Examples of contact fungicides are:
- Copper sulfate fungicide: Examples are Cuprofiix Ultra 40, Cuproxat. They are used for various vegetables such as cucumber, tomato, pepper etc.; they are used to control several fungal diseases such as leaf spots, downy mildew, and late and early blights.
- Copper hydroxide fungicides: Examples are Champ Dry Prill, Kocide 2000 etc.; they are used to control fungal disease such as anthracnose, leaf spot, bacterial spots and blight in various crops.
- Copper oxychloride and Copper hydroxide fungicides: an example is Badge X2. They are used to control diseases such as bacterial and fungal leaf spots and blights in various fruit vegetables.
- Copper octanoate fungicide: Example is Camelot OOG; they are used in controlling fungal diseases such as bacterial and fungal leaf spot, powdery mildew, downy mildew, early and late blight in various vegetables such as lettuce, onion, tomato, pepper, and other leafy vegetables etc.
- Hydrogen-dioxide and peroxyacetic acid herbicides: Example is ZeroTol; used in controlling downy mildew, powdery mildew, root rots, leaf spot and blights of various fruit vegetables such as cucumbers, eggplant, tomatoes, and pepper.
- Mineral oil: Example is SuffOil XOG; used to control powdery mildew for vegetables.
- Pentachloronitrobenzene (PCNB) fungicide: Example is Terraclor 400; controlling fungal diseases such as root and stem rot, damping off in vegetables.
- Potassium bicarbonate fungicide: Example of these fungicides are Milstop OG and Kaligreen OG; they prevent powdery mildew in many vegetables
2. Systemic fungicides:
These are the types of fungicides that when applied are absorbed into the plants’ tissue to fight against the pathogens within the system of the plant. They are also called penetrants and mobile fungicide. They are best used when the disease has emerged, examples of systemic fungicides are:
- Copper sulfate pentahydrate fungicides: Example is Phyton 35. They are used to treat and control Botrytis blight, late blight on tomato, fungal and bacterial leaf spots, downy mildew, powdery mildews.
- Cyanamid fungicide: Example is Ranman. They are used to control and treat Pythium damping-off of tomato and downy mildew on a basil plant.
- Phosphorus acid Fungicides: Example is Fosphite. They are commonly used to treat and control root rots, downy mildew, powdery mildew in many fruit vegetables.
- Propamocarb hydrochloride Fungicides: Example is Previcur Flex. They are used to control and treat fungal diseases such as Root rot and Damping off in vegetables such as tomato, pepper, lettuce, cucurbits etc.
- Streptomycin sulfate fungicides: Example of these fungicides is Agri-mycin 17OG; they are used to control and treat fungal diseases such as Bacterial spot and speck in tomato and pepper.
- Thiophanate methyl fungicides: Example of this fungicide is 3336 F; they are very effective at controlling Anthracnose, botrytis blight and powdery mildew in vegetables and legumes.
This is the systemic fungicide list registered for agricultural uses.
Types of fungicides based on their degree of activity
Under this category, we have two types of fungicides; namely
1. Narrow spectrum fungicides:
These are the types of fungicides that effective against only a few pathogens, usually closely related pathogens. Narrow spectrum fungicides are pathogen-specific; they are often systemic herbicides. Examples of narrow spectrum fungicides (active ingredients and brand names) are:
- Triforine fungicides: Funginex and Saprol
- Mefenoxam metalaxyl fungicides: Apron XL, Ridomil Gold, Subdue Maxx
- Carboxin fungicide: Vitavax
- Fluxapyroxad fungicides: Merivon and Priaxor
- Penflufen: Emesto
- Penthiopyrad: Fontelis and Vertisan
- Fluopyram fungicides: Luna
- Cyprodinil fungicides: InspireSuper, Switch, Vanguard
- Quintozene fungicides: PCNB, Blocker
2. Broad-spectrum fungicides:
These are the types of fungicides that are effective at controlling a wide range of pathogens; they are usually contact fungicides. Examples of broad-spectrum fungicides (active ingredients and brand names) are:
- Thiabendazole fungicides: Mertect
- Triflumizole fungicides: Procure and Terraguard
- Difenoconazole fungicide: Inspire Super, Stadium etc.
- Flutriafol Fungicides: Rhyme, Preemptor
- Metconazole fungicides: Quash
- Myclobutanil fungicides: Eagle and Rally
- Propiconazole fungicides: Banner Maxx, Honor Guard, Procure, Quilt.
- Tebuconazole fungicides: Folicur and Toledo
- Tetraconazole fungicides: Mettle
- Prothioconazole fungicides: Proline, Prosaro, Stratego, YLD.
- Azoxystrobin fungicides: Abound, Quadris, Heritage, Stadium
- Fluoxastrobin fungicides: Evito
- Fenamidone fungicides: Reason
- Pyraclostrobin fungicides: Cabrio, Headline, Priaxor
- Fludioxonil fungicides: Cannonball, Maxim, Medallion, Scholar.
- Fluazinam fungicides: Omega
- Copper fungicides: Badge, Champ, Cueva, Kocide fungicide, Nordox
- Mancozeb fungicides: Dithane, Manzate
- Metiram fungicides: Polyram
- Thiram fungicides: Thiram
- Ziram fungicides: Ziram.
- Captan fungicides: Captan
- Chlorothalonil fungicides: Bravo, Daconil 2787, Echo, Initiate
These are the types of fungicides used in agriculture; they are registered in the United States for commercial crop production.
How to prevent fungal diseases
Apart from using fungicides to control fungal diseases, there are ways you can avoid fungal diseases; they are called cultural practices. These ways are:
- Proper ventilation around the farm by adopting the best spacing requirement.
- Applying water around the root zone of the plant instead of the leaves to avoid the spread of diseases or spores produced by the fungi.
- Clean up all fallen leaves of infected plants.
How to apply fungicides
Lastly, it is imperative you know how to apply fungicides so as to have the best result. You do not apply fungicides wholesomely; it has to be diluted with water at the recommended rate before application. Please adhere to the recommended rate. Ways of applying fungicides are:
- Seed dressing: This method of fungicide application is commonly used prior to planting. It involves mixing fungicides with planting materials such as seeds, suckers, corms, rhizomes etc.; this method is commonly used as a preventive measure.
- Foliage spray: This is the conventional method of applying pesticides. It involves spraying fungicides, at the recommended rate, on the foliar parts (leaves) of the plant. It could be used for either preventing or controlling a fungal disease.
- Injection via truck: This is the method of fungicide application used in agro-forestry. The fungicide is injected via the trunk where it is transported through the xylem to other parts of the tree where it resides.
In an intensive system of cultivation such as the greenhouse, fungicide powder should be applied as smoke, mist, fog or aerosol.
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