Home Greenhouse Beast: the tobacco whitefly is every greenhouse grower’s nightmare

Beast: the tobacco whitefly is every greenhouse grower’s nightmare

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The louse uses genetic techniques to protect itself.

The tobacco whitefly is not a fly, but a louse related to aphids. It is originally a subtropical species, native to India and Pakistan. Like many other forms of life, it has benefited from globalization. She has traveled the world for decades, especially with ornamental flowers and leafy vegetables that are moved great distances between growers and buyers, which is very unsustainable. During the 1980s she also found herself in Belgium and the Netherlands.

The tobacco whitefly is not a fly, but a louse related to aphids. It is originally a subtropical species, native to India and Pakistan. Like many other forms of life, it has benefited from globalization. She has traveled the world for decades, especially with ornamental flowers and leafy vegetables that are moved great distances between growers and buyers, which is very unsustainable. During the 1980s she also found herself in Belgium and the Netherlands. The animal is a nightmare for greenhouse growers. It parasitizes over five hundred plant species, including tomatoes, cucumbers and begonias. Tobacco whitefly is said to have been introduced to us via ornamental plants such as Chinese rose and poinsettia. It’s a utopia to assume that we’ll ever get them completely under control, especially since critters can fly very well. Locally limiting the damage seems to be the most feasible. Tobacco yellow-white whiteflies are barely a millimeter long. They have a hunchbacked appearance, with white wings that they fold over their bodies. They live on the underside of the leaves, where they suck the juice from the phloem: the tissue responsible for transporting sugar-rich nutrients. Once the females emerge from their pupae, they begin to lay tiny eggs on a leaf, totaling between fifty and four hundred eggs. Quarter-millimeter larvae emerge, which move on the leaf until they have found a suitable place for their food. There, they suck each other full of juice for weeks. The length of the whitefly’s life cycle depends on the temperature: if it is above 20 degrees, it lasts 22 days – then adults live two weeks. At lower temperatures, a cycle can last 70 days and critters can live for up to two months. Everything then takes place a little more slowly. The main damage to the plant is not caused by the loss of sap, nor by the waste that aphids secrete on the assembly line in the form of “honey” – which makes the plants sticky and susceptible to fungi. The main problem is that the tobacco whitefly carries over a hundred viral species, which can be found in its host plant and cause disease. Insects are able to escape the defense mechanisms of a plant. They use exceptional tactics. The trade journal Cell reported the discovery of a scientific first: an insect that extracted a gene from a plant in order to escape the plant’s resistance to its presence. It is the gene that protects a plant against its own poison. The insect has also acquired resistance to plant poisons. Research has shown that disabling the gene makes whiteflies more vulnerable to plant poison, which offers a prospect for the development of an effective pesticide. Tobacco whiteflies have also developed resistance to chemical pesticides. Growers are now mainly focusing on biological control with predatory bugs and parasitic wasps in their greenhouses, which attack aphids. However, they do not control more than one population. Extermination is no longer an option. Globalization affects us in several ways.


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