How can we be sure Biopesticides are safe?
Many people, understandably, have lots of concerns when they hear the word ‘pesticide’, especially in connection with things they might eat, like olives and almonds. The consortium partners in the BIOVEXO project share these concerns – we want to know that the end products we are developing will not harm humans and, importantly, also not harm the environment. For this reason, we have dedicated an entire project work package to testing the sustainability and toxicity of the formulae we are using.
The BIOVEXO project is helping to develop innovative biopesticides to target both the Xylella fastidiosa bacterium (X-biopesticides) and the main vector that spreads the bacterium, the spittlebug (V-biopesticides). On the occasion of World Environment Day, BIOVEXO would like to explain what we are doing to ensure that the fight against Xylella also contributes to maintaining a healthy environment. Because BIOVEXO’s solutions are being developed to fight against Xylella and its vector, it is necessary to assure that, in case they reach non-target organisms (such as aquatic organisms and arthropods) they are not going to induce any adverse effect.
The legal framework for pesticides
First of all, it is important to understand that there are legal requirements covering the introduction of new products to the market. Plant protection products cannot be placed on the market or used without authorisation from regulatory bodies. They may only be approved if a risk assessment shows that they undoubtedly have no unacceptable effects on the environment. A dual system is in place: the European Food Safety Authority (EFSA) evaluates active substances used in plant protection products, and then individual Member States evaluate and authorise the use of products at national level.
The requirements for demonstrating that new plant protection products pose no unacceptable risk are set out in various plant protection regulations, such as: REGULATION (EC) No 1107/2009 of the European Parliament and of the Council of 21 October 2009, concerning the placing of plant protection products on the market; and in COMMISSION REGULATION (EU) No 283/2013 of 1 March 2013, setting out the data requirements for active substances.
The former Regulation aims to ensure a high level of protection of both human and animal health and the environment whilst, at the same time, seeking to safeguard the competitiveness of agriculture in the European Union. The latter Regulation requires that different ecotoxicological studies are undertaken. For example, to ensure the product will be safe when it enters the water system, the effects on aquatic organisms, such as fish, aquatic invertebrates (Daphnia), and algae must be reported. The effects on other important organisms in the field, such as arthropods (like bees), must also be investigated and reported.
How is BIOVEXO ensuring its products are safe for the environment?
The BIOVEXO project is currently in the process of conducting experiments on algae. Green algae have very important functions in the environment. They have the ability to convert solar energy and carbon dioxide (CO2) into biomass and oxygen. They play a vital role in aquatic ecosystems by forming the energy base of the food web for all aquatic organisms. Actually, they are so good that even humans eat them! Given their importance to the food chain and the environment, it is quite right to test new plant protection products to ensure they do not have negative effects on algae. Experiments with honeybees are also on-going. Acute oral and contact toxicity to adult worker honeybees is being assessed. In addition, we are also studying whether there is any impact on the behaviour of adult worker honeybees.
Bees play an important role in the pollination of a wide range of crops and wild plants. The production of about 80% of the 264 crop species cultivated in the European Union depends directly on insect pollinators, mostly bees, and the global annual monetary value of pollination is estimated to be billions of dollars. However, there has recently been wide-spread concern over honeybee populations around the world. It is already known that some pesticides (such as neonicotinoids) represent a risk to wild bees and honeybees.
In addition to pollination, bees also provide us with foods and food services, such as: honey, wax for food processing, propolis (a resin-like material which can display bacteri-, viri-, and fungi-cidal, as well as anti-inflammatory properties), and royal jelly as a dietary supplement and ingredient in food.
Indeed, honeybees are so vital for crop pollination that some enterprising farmers have tried using some very creative methods to attract them! These methods include using loudspeakers in the fields to play recordings of buzzing bees. The idea is to trick bees into believing there is a significant quantity of nectar and pollen around attracting other bees. You could call it a ‘honey-trap’! Hard to believe, but such ideas really have been used in orchards and farms! It just goes to show the lengths that farmers will go to make sure that their crops receive adequate pollination. Again, this just underlines how important honeybees and other pollinators are to agriculture.
Preparations for tests on the effects of our products on Daphnia are currently being made in our laboratories. Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm in length, belonging to the order of Anomopoda. They are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the jumping movements of fleas! But there is no need to worry when you go swimming – they won’t bite you!
BIOVEXO’s experiments with fish have not started yet as all experiments with vertebrates require prior approval from the Ethics Committee on Animal Experimentation and from the regional government. But, as a bit of background information: one of the fish species more commonly used in research are the Zebrafish (Danio rerio). Actually, they are one of the few animals that have been flown into space! The zebrafish is named for the five blue stripes on the side of the body, which resemble a zebra’s stripes. If you’re planning to do product testing, be careful not mix your zebrafish and Daphnia in the same tank… otherwise you’ll swiftly find the small water fleas eaten by the fish!
How exactly is BIOVEXO making sure its biopesticides will be safe?
The algae tests currently being conducted consist of adding 1ml of BIOVEXO’s biopesticides to cell cultures of Raphidocelis subcapitata at 5×10^5 cells/mL. Various batches are being tested in reference to control samples. These are then subjected to 3 days (72 hours) of agitation at controlled temperatures of 21± 2ºC under continuous, uniform, fluorescent illumination. Cell counts of the algae are taken every 24 hours. After 3 days the batches are tested to check whether they meet specified criteria (average specific growth rate >0.92/day; day-by-day %CV<35%; average %CV<7%).
For the honeybee tests, acute contact toxicity tests are being performed (seeking to determine the median lethal doses (LD50)) for short time exposure of honeybees to the test item by performing dose/response designs. Caged honeybees are kept without feed for up to two hours and then provided with a 50% w/v sucrose solution. The sucrose solution contains the test item or dimethoate (as positive control) in carefully calculated concentrations. After feeding, the remaining sucrose solution is weighed to allow calculation of the real dose uptake. The bees are subsequently observed to measure any adverse effect of the product being tested.
For the testing on the water fleas, batches of young Daphnia will be placed into test vessels before being exposed to the plant protection products. They will be monitored for 2 days (48 hours) and immobilisation/death rates calculated to ensure they are within acceptable/normal boundaries.
Tests on fish will only be conducted once the results on algae and daphnia have been obtained and taken into account.
Final words
BIOVEXO is fighting Xylella and protecting olive and almond trees across Europe, but in the development of innovative biopesticides it is essential to make sure we are not having adverse effects on non-target species. The BIOVEXO project was designed with this important consideration in mind, dedicating an entire work package to the testing of its products. This will help ensure they are safe and are one step closer to the market when the project is concluded. If you’d like to follow the work of the BIOVEXO project and stay up to date on the fight against Xylella, please sign up to our Newsletter and follow us on Twitter, Instagram, LinkedIn, or Facebook.
