Trifloxystrobin is a broad-spectrum fungicide used to protect various crops from fungal diseases. It belongs to the strobilurin class of synthetic chemicals, known for their effectiveness in plant disease management, safeguarding plant health and contributing to crop yield.
How Trifloxystrobin Functions
Trifloxystrobin operates by inhibiting mitochondrial respiration within fungal cells. It is classified as a Quinone outside Inhibitor (QoI) fungicide, binding to the cytochrome b complex III at the Qo site in the fungal mitochondrial respiratory chain. This action disrupts the electron transfer process, which is how fungal cells generate energy. Without this energy, the fungus cannot grow or reproduce, effectively stopping the infection.
Beyond its direct inhibitory action, trifloxystrobin exhibits both systemic and translaminar properties. Systemic movement means the fungicide can be absorbed by the plant and transported through its vascular system to protect new growth. Translaminar activity allows the fungicide to penetrate the leaf surface and move to the other side, protecting both upper and lower leaf surfaces. These properties enhance its effectiveness against established infections and help prevent new ones.
Where Trifloxystrobin Is Used
Trifloxystrobin is applied across a wide array of agricultural and horticultural crops. It is commonly used on fruits such as grapes, apples, pears, cherries, and strawberries. Many vegetables also benefit from its application, including cucurbits, leafy greens, carrots, asparagus, and fruiting vegetables. Furthermore, it finds use in cereals like wheat and barley, as well as on ornamental plants.
This fungicide is effective against a range of fungal diseases that impact these crops. It controls powdery mildew, rusts, scab, leaf spots, and blights. Application methods vary depending on the crop and target disease, but common approaches include foliar sprays, where the fungicide is applied directly to the leaves. It can also be used as a seed treatment to protect seedlings from early infections or as a soil drench for diseases affecting roots.
Environmental and Health Profile
Trifloxystrobin’s environmental fate involves its behavior in soil and water systems. It has low aqueous solubility and low volatility, suggesting a low potential for leaching into groundwater. While not expected to be persistent in soil or water, runoff into aquatic environments can occur, particularly after heavy rainfall.
Trifloxystrobin is highly toxic to aquatic organisms such as fish and aquatic invertebrates. Necessary precautions prevent runoff into water bodies to mitigate these impacts. It is considered less toxic to beneficial insects like honeybees and earthworms.
Human health is addressed through strict regulatory oversight of residue levels in food. Regulatory bodies like the Environmental Protection Agency (EPA) in the U.S. and the European Food Safety Authority (EFSA) establish Maximum Residue Limits (MRLs) for trifloxystrobin. These MRLs are legally enforceable limits on pesticide residue in food products. Compliance ensures food safety for consumers. For individuals handling the fungicide, wearing protective equipment is recommended to minimize exposure during application.
Preventing Fungal Resistance
Fungal resistance to QoI fungicides like trifloxystrobin is a concern in agriculture. Resistance develops when fungi mutate, overcoming the fungicide’s action, often from repeated use of the same class. A single nucleotide polymorphism in the cytochrome b gene can lead to an amino acid substitution, rendering it ineffective. This can result in cross-resistance, making fungi resistant to all chemistries in the same FRAC group.
Several strategies mitigate or prevent resistance development. Rotating trifloxystrobin with fungicides from different chemical classes prevents fungi from adapting. Tank mixing trifloxystrobin with other fungicides from different Fungicide Resistance Action Committee (FRAC) groups, especially low-risk protectant fungicides, is also recommended. Adhering to recommended application rates and timings ensures effective disease control without promoting resistance. Integrating trifloxystrobin into an Integrated Pest Management (IPM) program, which combines various control methods, further supports its long-term effectiveness.