U.S. Department of Agriculture (USDA) scientists in Illinois, USA, are investigating the role of anthocyanins in pest-control. They believe that the plant pigment can adversely affect crop pests such as the corn earworm caterpillar and the cabbage looper caterpillar that feed on it.
Anthocyanins are a plant pigment which give blackcurrants and flowers, such as petunias, their blue and purple colour. They absorb blue-green and UV light, protecting plant cells from high-light stress.
In the experiments the scientists used corn earworm caterpillars (Helicoverpa zea). H.zea damage is usually serious and costly because of the larval feeding preference for the reproductive structures and growing points which are rich in nitrogen.
The caterpillars were forced to feed on blue areas of petunia petals which contained higher levels of anthocyanins than the white areas. It was found that these individuals gained less weight than other individuals which were fed on only the white leaf areas. Further experiments found that isolated anthocyanins slowed the caterpillar’s growth rate.
Researchers at the National Physical Laboratory (NPL) are currently exploring the use of microwaves as a potential pest control method. Unlike traditional chemical pesticides, which indiscriminately kill all insects, microwaves would be able to target specific insect pests and not affect other insects in the area. This new application of microwaves could benefit farmers in the developing world by providing a cheaper and more environmentally-friendly alternative to chemical pesticides.
This approach uses microwave frequencies that only affect the target insect pest whilst ignoring other insects. The specific insect pests are identified and affected by the microwaves based upon their size and structure, with the microwaves tailored to fit the specific insect pest. This is done on a trial and error basis on species individuals before entering the field. There is still the possibility of killing “useful” or “neutral” insects (such as pollinators), however the risk of this is reduced compared to chemical pesticides.
The researchers are not only looking to kill the insect pests immediately but are also looking to disrupt their reproduction and communication systems. By making them infertile or reducing the insect pests’ ability to effectively communicate with each other they could reduce their long-term survival prospects.
Efforts to help developing countries increase their food security and to empower women should be considered together as both are dependent on one another. The FAO has said that if women had the same resource access in agriculture as men then food output in developing countries would increase by enough to pull 100-150 million people out of hunger (FAO Report). By comparing the work by BirdLife and Plantwise’s own plant clinics (plant clinics around the world) you begin to see the first signs of how empowering women can lead to increased food security.
Recently a project in Paraguay by Nature Canada (partnered with BirdLife) helped 478 women farmers in efforts to promote sustainable agriculture in the region. They aimed to balance conservation objectives, such as preventing deforestation and monocultures, with benefiting farmers.
They were successful in this and were also able to improve the awareness of gender equality as well as the rights of women. It has led to some women actively demanding their rights be respected and the formation of 10 committees by the women farmers who have successfully obtained municipal recognition.
Certain maize landraces obtained from South America have been found to have developed sophisticated defence strategies to cope with insect pests such as the spotted stemborer, Chilo partellus, it was reported today. These findings could help to increase maize yields and improve food security.
The spotted stemborer, Chilo partellus, is now a major pest in eastern and southern Africa, as well as South Asia where it causes yield losses of up to 88%. Since establishing in east Africa in the 1950s, it has spread to southern and central Africa. The distribution map on Plantwise.org shows the current distribution in Africa and South Asia.
The larvae tunnel extensively into stems and maize cobs causing weaknesses that may lead to stems breaking. They can also cause damage known as “dead heart”; this is when larvae crawl inside the sheath and tunnel into the heart of young shoots, killing the growing point, which leads to browning and wilting of the youngest leaves.