In the process of researching – advising farmers to take care of fruit trees and seeds, the research team has been very successful when combining a pair of nematodes – fungal diseases to treat and restore many seemingly ideal orchards. Can not salvage…
Nematode diseases:
Nematodes on pepper plants include ectoparasites and internal parasites. They attack the root system creating mechanical wounds, leaving many small holes in the roots, which are favorable conditions for fungi. Fusarium sp, Phytophthora sp penetrate the root system to cause rapid death and slow death in pepper plants.
Nesting nematodes create tumors on the roots
By observing the roots, it is easy to see that the nesting nematodes have formed large tumors (nodules) and blackened the roots. However, the mechanical wounds caused by the nematodes cause negligible damage, but most of the damage is because they pump saliva containing toxins into the plant when sucking the cell fluid, causing the plant to be stunted and depleted.
Nematodes are always present in the pepper root zone and are widely distributed at a depth of 5-40 cm.
On pepper, The nodular nematode Meloidogyme incognita causes root tumours (root tumors). The roots have big humps and have small holes, the roots are blackened and the leaves are bright yellow from the feet up, the plant grows poorly, absorbs water poorly and eventually dies with the whole plant, pull the tree up to observe the roots, especially the hairy roots are completely damaged.
The endoparasitic nematode Rotylenchulus reniformic mainly parasitic in the roots causing black rot, stunted growth, yellow leaves from the feet up, the root system is black rot, so the tree cannot live anymore.
The pepper plant’s roots have been mechanically wound by nematodes, Fusarium and Phytophthora fungi, following the wound, attack the root system, causing the plant to die faster.
Late leaf yellowing disease caused by Fusarium sp
Sometimes the disease is a combination of many other fungi such as Pythium sp, Rhizoctonia that invade the root system, causing slow death. When attacked by nematodes, it will be a good condition for the above-mentioned fungi to penetrate, making the roots weaker and less able to absorb water and nutrients to feed the plant.
Common symptoms are slow growth, leaves shrink, leaves turn yellow. Then the leaves, chains, burn gradually (die slowly) from the bottom up, not fall and wilt like dying quickly from the buds down, while the leaves have not yet yellowed.
Root rot, rapid wilt disease caused by fungus Phytophthora sp
Phytophthora sp is an aquatic fungus that lives in the soil, which can attack alone or in combination with other fungi such as Furarium sp, Rhizoctonia sp causing pepper plants to wilt and die quickly.
Observe the illustration
Locations commonly attacked by Phytophthora sp
The fungus Phytophthora sp usually attacks in four locations as illustrated: Leaves, string, root collar and roots. The most dangerous location is the root neck, the fungus destroys the vascular system, cuts off the transmission of water and nutrients, causing the plant to wilt and die very quickly.
Massively fallen green leaves, the main manifestation of rapid wilt disease
Phytophthora fungi are also known as aquatic fungi – due to their dormant and vigorous germinating spores, the mycelium thrives in rainy conditions. The fungus insidiously attacks the root system, when it appears on the tree, the fungus has attacked long before, causing serious damage to the roots. When the rain stops, the tree breathes strongly, so the tree wilts and dies. Rapid death is very difficult to treat because the signs only appear after the tree has been infected for a few months, so prevention is more effective than treatment. Aquatic fungi need water for fungal spores to germinate, so gardens must make drainage ditches to prevent water from entering other gardens.
The main causes of diseases caused by nematodes and fungi are:
- Imbalance of microbial flora in the soil
- The organic matter content in the soil has been depleted, the soil pH is low, and the drainage is not good
- Excessive use of fertilizers and pesticides
Measures to prevent fungi and nematodes:
- Chemical measures: Use the fungicides and nematodes on the market, then use organic fertilizers to stimulate the root system to grow again.
- Biological measures: Provide adequate organic fertilizers, attach importance to “soil health” to create optimal conditions for the biological struggle process in the soil. Using microorganisms against fungal diseases such as: Trichoderma .sp, Bacillus .sp, Pseudomonas .sp, Streptomyces .sp, symbiotic mycorrhiza…. Note, these antagonistic microorganisms will be very effective only when there is an abundant source of organic compounds available in the soil. Therefore, it is possible to combine with traditional organic fertilizers, compost of all kinds such as manure, coffee husks or agricultural by-products through composting, then water these microorganisms on this organic substrate.
Mechanism of action of Trichoderma .sp: Parasites on pathogenic fungi, secreting similar substances “antibiotic” to inhibit the growth of harmful microorganisms, compete for nutrients and living space with pathogenic fungi.
Mechanism of action of Bacillus .sp: Siderophere mechanism (Bacillus sp will secrete iron-retaining compounds, iron is an energy source for harmful microorganisms to multiply in number), parasitism on pathogenic microorganisms, secreting similar substances “antibiotic” to kill harmful microorganisms.
Mechanism of action of Streptomyces .sp: Actinomycetes Streptomyces sp secretes a large amount of enzyme chitinase, which is an enzyme that decomposes the cell membrane of pathogenic fungi, this same enzyme decomposes the membrane of nematode eggs and nematodes. So actinomycetes Streptomyces sp has a very high ability to control nematodes and fungal diseases.
After controlling nematodes and fungal diseases, it is necessary to apply organic fertilizers to stimulate the root system to thrive again.
Conclude :
In the process of cultivating crops in general, we must pay attention: The pair of nematodes and fungi always go hand in hand. When treating nematodes must always be combined with the prevention of fungal diseases. Nematodes make the ability to absorb water and nutrients poor, increase the cost of fertilizer investment and labor for farmers, creating conditions for pathogenic fungi to attack the root system. If only treating a single fungus or nematode, the farmer can only do half of the job, the other half “neglect” but the risk of harm is still there. According to the illustration, the prevention of fungus Phytophthora sp should actively perform in all four positions leaves, chain, root collar and roots. After being reassured that the density of fungi and nematodes is under control, the next step is to find a way for the root system to thrive so that pepper and other crops can grow normally and have enough energy. absorb nutrients to raise fruit, sprout branches… meet the expected yield and especially give high yields in the following years
All plants that grow on the soil, mainly fruit trees and seeds, are subject to damage by nematodes – fungal diseases. Farmers always have to take care of and protect the root system in the context of always being threatened by this couple, while “health of the earth” getting weaker…
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