Did you know that the pre-harvest loss caused by insects in fruits and vegetables ranges from 37-55%? I find this quite amazing and that in addition to the direct damage caused by insects on different parts of the fruit trees, these insects can also transmit bacterial diseases further reducing the productivity (sometimes even death) of trees. Insect pests that transmit bacteria diseases cause losses in fruit production in Europe of half a billion Euros annually.
It is crucially important to reduce disease infections caused by insects and my IUPAC Next Generation project is specifically on this topic. I’m particularly interested in developing environmentally friendly alternatives that are safe to non-target organisms and keep chemical pesticides to levels that minimize risks to human health.
Plants produce natural odors (called volatile organic compounds or VOCs), which are used by insects to find food and reproduce. Those smells can be attractive and used as lures to trap insects and repellent for scaring off pest insects. A combination of attractive and repellent compounds can be an effective push-and-pull strategy in insect control. The idea of my IUPAC project is to explore how VOCs can be used as biologically active ingredients in crop protection and to also develop an efficient dispenser that ensures controlled release rates of VOCs, suitable for use in the field, through encapsulation in nanofibers made of biodegradable polymers. This approach will on one hand repel insects and on the other will attract them to traps – thus a more sustainable management of fruit trees from damaging insects.
One of the major drawbacks in this approach, especially in field conditions, is high volatility of the compounds so they aren’t very effective over longer periods. For that reason, it is important to improve the longevity of those substances so that they are less volatile and more effective.
With the grant I received from the IUPAC Next Generation Project I have been able to make some significant steps towards my goal of finding a sustainable and environmentally responsible solution to insect management.
Because clove oil has already been reported as repellent to several species, including the Asian citrus psyllid and the Asiatic pear psyllid I have used this in my first formulation of repellents. It presents a good repellency, masking the natural odors the pear trees emit and so may work in avoiding the insects from feeding and laying eggs on the trees. However, there are two other essential oil compounds I’m going to test.
During the spring and summer, I have sampled the volatiles from pear trees in the field, in order to investigate which odors they are emitting and then test what are the most relevant volatiles attractive to insects. Now I am analyzing the relative amounts of every component and will then start the behavioral experiments in the lab with several formulations or mixtures of components present in the plant odor bouquet. The final formulation will be used to mimic trees, attracting the insect to a sticky trap. The major challenge of that part of the project will be establishing the correct concentrations of each component to produce the perfect attractive compound.
Nano-winter is coming! Over the winter I will start the nano-formulations, and have selected several biodegradable polymers to formulate the dispensers. Thereafter I will analyze the release rates of VOCs from nanofibers, adjusting them to a constant discharge of odors and the most promising ones will be tested in the field next season.
All of this has been both exciting and challenging. I’ve faced some problems with equipment which is frustrating and yet have found opportunities I hadn’t expected. I have the opportunity to contribute a chapter about smart textiles for agriculture in a book about nanosensors and nanodevices. This is a positive spin off to my IUPAC Next Generation project that I am glad to be part of and contributes to the advances in agriculture technologies.
Bruna Czarnobai de Jorge