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    Natural Plant Compounds Provide UV Protection

    Plant UV Protection

    Scientists at the University of Malaga have identified a group of natural molecules in plants that act as natural sunscreens to protect against UV-B radiation, which can damage DNA and hamper growth. This protection is provided by the plant cuticle and comes from a suite of natural plant chemicals called phenolics.


    UVB is the medium-wavelength radiation from sunlight, with wavelengths between 280-315 nm. This type of radiation accounts for about 10% of the total solar UV radiation that reaches Earth’s surface. It is the most common form of UV radiation that affects plants.

    Depending on the species and experimental set-up, UVB exposure can have different effects on plant physiology. For example, it can increase the accumulation of secondary phenolic compounds such as quercetin and cyanidin in guar beans (Cyamopsis tetragonoloba) and urad beans (Vigna mungo L). However, the use of UV blocking covering materials can reduce the accumulation of these compounds.

    Exposure to UVB can also have positive effects on the plant’s defense against biotic agents. The interaction between ambient UVB and abiotic stress factors can trigger the formation of soluble proteins in the leaves that can protect the plant against pests and viral diseases. In particular, a recent study showed that high levels of ambient UVB can induce resistance to rice blast disease caused by the fungus Magnaporthe oryzae by stimulating the expression of the HY5 gene.


    The shortest UVC wavelengths are also the most dangerous. They penetrate the skin and cause damage to chromosomes. Fortunately, most of the UVC that reaches Earth is absorbed by the ozone layer. However, artificial UVC can still be used to kill bacteria and viruses. This type of UV is also known as germicidal UV.

    The most effective UV treatments include those that increase stomatal opening and photosynthesis. They can also stimulate the production of secondary plant compounds, such as anthocyanins and total phenolics. However, they must be delivered in a controlled manner to prevent burning of leaves and to avoid affecting the plant’s physiology.

    Studies of the effects of greenhouse covering materials on the agronomic performance of crops usually have pests and viral diseases as their primary objectives, but these materials have a range of other benefits, too. For example, they can increase crop yields and improve the quality of harvested produce. One study found that strawberries had a higher color, size, and weight when exposed to UVB. Another study found that lettuce plants had better shape and biomass production when exposed to UVB.


    UVA is a type of electromagnetic radiation that has a wavelength between 10-400 nanometers and is also known as UV light. It is one of the most common types of radiation that reach the Earth and can be found in sunlight, but it is less harmful than UVB and UVC.

    In contrast to the detrimental effects of UV-B and UV-C on microorganisms, UVA has a positive impact on them by upregulating certain specialized metabolites. These metabolites can help plants fight off pathogens and herbivores.

    Many studies have shown that UVA increases the production of plant hormones such as salicylic acid (SA) and jasmonic acid (JA). These hormones are involved in defense responses against biotrophic pathogens and herbivory. They also improve the vigor of the plant and increase its growth rate. In addition, UVA can also stimulate the production of resin in a plant, which is essential for its quality and potency. This can have a huge impact on the final product.


    Plants sense UVB and respond to it by deploying antioxidant defenses, increasing photosynthesis rates, and accumulating “sunscreen” flavonoids. Mutant screens have identified several factors that participate in the UV-B response, including the HY5 gene and the UVR8 monomer. UVR8 binds to COP1 and RUP2 in plants that are acclimated to high UV-B. This binding reduces the permeability of the photosynthetic membrane and prevents oxidative stress in plant cells.

    Phenylpropanoids, such as kaempferol-3,7-dirhamnoside from Achillea biebersteinii15 and Achillea millefolium16 and caffeic acid, epigallocatechin, epicatechin, and rosmarinic acid from Dalloa hebecarpa17 and Plectranthus ecklonii Benth18, also have anti-UV properties. These compounds can reduce oxidative damage and decrease penetration of UV radiation into the palisade and spongy mesophyll tissues.

    Many studies have found that the use of UV blocking materials has a positive effect on crop physiology and productivity, but other factors need to be taken into account as well. For example, a study conducted in the UK showed that the use of UV-blocking films reduced the amount of phenolics and anthocyanins in red lettuce crops.

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    Protection Measures for Invasive Pests and Endangered Species

    The Plant Protection Bulletin

    Plant protection bulletin is a peer-reviewed journal that publishes original research papers, rapid communications and reviews covering all aspects of modern plant protection. The journal focuses on issues that are of specific concern to National Plant Protection Organizations.

    APHIS works to protect agriculture, natural resources and the environment by preventing the entry into the United States of invasive pests and diseases. This is achieved through effective regulation and policy.

    Pest Reports

    Identifying pests is an important step in protecting plants and promoting trade. The information gathered by pest reports is used to determine the level of risk that exists for different commodities and areas. The CFIA tracks pests through a variety of methods, including scouting, using online reporting tools such as iNaturalist and EDDMaps, and collecting samples from suspicious plants or crops.

    Invasive plant pests are a serious threat to global agriculture, natural ecosystems and public health. They can wreak ecological havoc and require expensive eradication or management programs.

    To protect against them, PPQ has deployed an advanced quantitative tool called the Pest or Pathogen Spread (PoPS) forecast. This tool simulates the probability of an invasive pest or pathogen making its way from one place to another, giving regulators and growers an opportunity to take preventative measures. In addition, PPQ is testing a number of early warning systems that can predict the likelihood of an outbreak based on environmental factors.

    Pesticide Use Limitations

    A pesticide is considered a potential threat to federally listed endangered or threatened plants and animals when it is used in an area that has been designated as critical habitat for those species. The directions for use on the pesticide label will typically specify requirements to obtain a Bulletin in these cases. However, following the Bulletin does not excuse the pesticide applicator from legal responsibility if a species is killed or otherwise harmed by the application of a prohibited substance.

    A large body of European legislation regulates the marketing and use of plant protection products. In the EU, EFSA performs risk assessments of active substances and sets limits for residues in foods (maximum residue levels or MRLs) while Member States evaluate and authorise plant protection products at national level. In addition to MRLs, EFSA also evaluates consumer risks, including possible endocrine disruption. The process of modifying MRLs is complex, and involves the submission of an application by a Member State (EMS) to EFSA in order for EFSA to prepare a scientific opinion (reasonable opinion). EFSA’s consumer risk assessment is based on information from a wide range of sources, including published literature and government legislation.

    EPA Endangered Species Protection Bulletins

    When endangered species of plants or animals are at risk of becoming extinct, the Endangered Species Act requires that protective measures be put in place. Threats to the species could be caused by anything from habitat destruction, pollution, over-harvesting and vandalism.

    Once a risk assessment and/or formal consultations with the Services are completed, EPA will either change pesticide product labels or establish geographically specific “endangered species protection bulletins” for each individual pesticide active ingredient that may affect a listed species in its jurisdiction. This EPA program is a voluntary interim program until such time as the use limitations are enforceable on the pesticide product’s label.

    Pesticide products that require a bulletin check will contain a statement on the label directing the pesticide user to a EPA website called Bulletins Live! Two. The site allows the pesticide user to enter the geographic area and month for which the pesticide application will take place and then checks the database for any enforceable use limitations for that specific location at that particular time of year.

    EPA Registration Numbers

    EPA requires all companies that produce pesticides or pest control devices to register those products with the agency. Those who register pesticides are called “registrants.” A company must have a “company number” to become a registrant. Once a company has a company number, it can apply for an EPA establishment number. This number must appear on all product labels, including supplemental ones for distributors and special local need registrations.

    The EPA establishment number is a four-digit number that corresponds to the final pesticide production facility. State abbreviations typically appear after the establishment number, for example MO, which indicates that a product was produced in Missouri.

    EPA’s Endangered Species Protection Bulletins establish geographically specific pesticide use limitations to protect waterways, endangered fish and aquatic organisms, plants, insect and other animals, their critical habitats, and the ecosystems on which they depend. EPA issues the Bulletins as part of its regular registration review process. EPA’s registration review process is required by the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and its amendment, PRIA.

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