Tired of facing crop diseases that never seem to end? Want to use less pesticides but afraid of more infections? Try chitosan --- a natural, non-toxic alternative that focuses on boosting plant defense instead of killing pathogens.
What is chitosan?
Chitosan is a polysaccharide derived from chitin, a substance found in the shells of shrimp, crabs, shellfish, insects, and fungal cell walls. Many chitosan products typically use crustacean waste as a chitin source because it is the most commercially available. This also makes chitosan a fully natural and non-toxic substance. To produce chitosan, chitin undergoes a chemical process known as deacetylation. This makes it more versatile and safe for humans and the environment.
Shrimp shell waste --- one of the chitin sources for chitosan production. (Chitosan Global, 2024)
What are the uses of chitosan?
Chitosan is widely used in many different fields. In agriculture, chitosan is used as a plant biostimulant, which means that it can stimulate plant growth. There are many plant biostimulants in the market, all of which stimulate plant growth in different ways. Chitosan does this mainly by boosting plant defense responses and through its antimicrobial properties. Besides that, it helps plants tolerate environmental stress better and promotes plant growth.
How does chitosan protect plants from diseases?
Chitosan can protect plants in two ways:
Antimicrobial properties
Chitosan directly acts on plants to trigger their defense responses. It functions as an elicitor, stimulating the production of antimicrobial compounds such as phytoalexins, phenolic compounds, secondary metabolites and pathogenesis-related proteins. These compounds are naturally produced by plants when they are infected to fight against pathogens. Chitosan also triggers the formation of physical barriers, for example making cell walls thicker with lignin and helping wounds heal faster.
Antibacterial activities of chitosan: altering pathogen cell membrane, damaging DNA and blocking metal ion absorption (Gritsch, 2019)
Chitosan can also act on pathogens such as fungi, bacteria and viruses. Due to its positive charge, chitosan interacts electrostatically with the negatively charged cell walls and membranes. This disrupts the cell wall and membrane structure, causing the cell contents to leak out and the pathogen to lose vital functions and protection. Since this mechanism of action works on pathogens which have cell walls and cell membranes, many diseases caused by fungi, bacteria and viruses can be controlled with chitosan.
By boosting plant immune systems and protecting them from diseases, chitosan helps to lessen the stress faced by plants due to diseases. This allows them to focus more energy on growth and production instead of fighting infections.
Why can't I just use pesticides to deal with it?
While pesticides are very effective, using them as a first resort is just a short-term solution. In professional cultivation, preventing disease infection is more sustainable than curing infected plants. Hence, alternative pest control methods such as chitosan should be prioritized first, and pesticides should be used as a last line of defense only when everything else does not work.
This is because overusing pesticides can lead to pathogen resistance. If pesticides are used frequently for a long time, the active ingredients can stop working. By replying on alternative pest control methods such as chitosan, you can ensure that pesticides remain effective for emergencies.
Using chitosan can help crops stay ahead of the disease cycle. It stimulates plant defenses to keep them in a state of heightened immunity against diseases. This way, plants detect diseases more easily and can deal with them before infection happens. Besides that, chitosan is also non-toxic and does not leave any harmful residue, making it safe for humans and the environment.
What type of diseases can I use chitosan for?
For growers, chitosan serves as a versatile, broad-spectrum shield against most destructive pathogens. Here are a few examples below:
In durian orchards, it helps in suppressing Phytophthora and Fusarium diseases by disrupting fungal membranes and preventing infections in roots.
Papaya fruits with anthracnose.
For fruity and leafy crops, it reduces anthracnose by preventing fungal spore germination, while also helping plants fight mildew infections.
What other benefits does chitosan have?
Other than boosting plant immunity and pathogen suppression, chitosan also improves environmental stress tolerance and promotes plant growth.
Environmental stress tolerance
Environmental stress such as heat, drought, and salinity can lead to water loss, chlorophyll degradation, protein denaturation, reactive oxidative species (ROS) accumulation and other detrimental effects. these will disrupt normal cell functions and slow down plant growth, eventually causing lower quality yields.
Chitosan alleviates plant stress by enhancing antioxidant activity for ROS scavenging. It also reduces water loss by retaining water and regulating transpiration. Chitosan increases chlorophyll content to maintain photosynthetic rates during stress, and stimulates production of stress-related proteins and metabolites.
By helping plants deal with stress better, they can focus on growth and fruit production instead of suffering in stressful conditions.
Promotes plant growth
Chitosan has been shown to improve water and nutrient availability and uptake, and increase photosynthetic rates. This allows plants to take in more nutrients and produce more energy, which in turn improves the vegetative growth, fruit production and fruit quality.
Another way that chitosan helps plant growth is through seed germination. Seeds applied with chitosan show better germination rates and more uniform seedling growth. chitosan does this by forming a film around seeds, increasing moisture absorption and retention in seeds.
When should I apply chitosan?
You may use chitosan in the following situations:
Disease prevention (early and routine):
The most effective use of chitosan is before infections happen. Regular application stimulates the plant's immune system and keeps it ready to naturally fight pathogens.
During disease outbreaks:
Apply chitosan when environmental conditions favor outbreaks (such as rainy seasons or humid conditions). It prevents major infections and restricts pathogen activity by triggering plant defenses, ensuring that infection levels do not cross economic injury level.
At the seed and seedling stage:
Use chitosan as a seed soak or soil drench during germination. This ensures uniform emergence, protects vulnerable young roots from damping-off, and establishes vigorous growth early on.
After pruning or harvesting (wound healing):
Open wounds from pruning or fruit harvesting encourage pathogen infection. chitosan triggers wound healing and accelerates tissue repair, restricting pathogens such as Phytophthora spp. from entering.
What makes WUXAL Chitosan different?
Unique formulation
unlike other chitosan product, WUXAL Chitosan also contains other nutrients to enhance chitosan function. Nutrients such as N and K support plant growth, while micronutrients such as B, Fe, Mn and Zn boost stress and pathogen tolerance. Applying WUXAL Chitosan gives the benefit of micronutrients without having to apply them separately.
Performance - enhancing additives
WUXAL Chitosan contains performance-enhancing additives that maximize nutrient delivery to leaves in a few ways listed below:
Create the optimal conditions for nutrient absorption: Buffering and chelating agents stabilize pH range and chelate heavy metal mirconutrients.
Maximize nutrient absorption: Surfactants and anti-evaporants increase droplet surface area and reduce nutrient loss from spray evaporation.
Suitable even in bad weather: Stickers prevent rain from washing the nutrients away and humectants re-wet nutrients dried in the sun.
Compatible for product mixing: These additives also make WUXAL Chitosan compatible with most WUXAL products and registered pesticides, reducing workload and improving efficiency.
WUXAL Chitosan is an excellent choice if you're thinking about adding chitosan into your fertililizer program. For more information, send us a message at +60 12-531 8161.