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Alpha and Beta get Closer to the Whitefly Pest

A range of ergonomically superior microscopes from Vision Engineering are now being used by entomologists within the European Whitefly Studies Network to assist their studies into insect pests. The Tobacco Whitefly, Bemisia tabaci is one of the world's worst agricultural insect pests and poses a significant threat to agriculture.

To underpin research into this pest the European Whitefly Studies Network (EWSN) was established. EWSN involves scientists and industrialists from all over Europe who together lead the multi-disciplined research to find ways of combating this destructive insect pest. Using the ergonomically advanced microscopes from Vision Engineering, researchers are studying the effects of a range of crop protection products on whiteflies.

The Tobacco Whitefly (Bemisia tabaci) is perhaps the world's number one insect pest today, threatening agriculture worldwide. The damage caused by this tiny pest is twofold - not only can their infestation destroy individual plants by sucking out sap, but plant viruses that they can transmit can infect and destroy many different species of crops.

A suitable field crop can host billions of whitefly, with every female having the potential to lay up to 250 eggs. Of these, it only takes one insect to acquire a plant virus that can then be passed to each new plant that the adult sucks sap from. Once present in the plant, every subsequent whitefly that feasts on sap from that plant may become a carrier, transmitting the virus throughout the crop or even on to other plant species.

Prior to the early 1990's, whitefly infestations were a problem but not serious in comparison to other pests. Then, something alarming happened to the American whitefly population - they developed resistance to the commonly used insecticides. The insect was commonly referred to as a 'superbug' that could feed and breed, immune to most attempts to control it. In one year alone, this insect species cost US agriculture $500,000,000 in damage. The battle was on, to find ways to control these pests. Efforts to control the spread of this superbug were hampered by the discovery that infested ornamental plants, such as poinsettia were being shipped worldwide, spreading the insect to every continent.

The centre of the battle against whitefly pests such as these, is focused through the many scientists that comprise the European Whitefly Studies Network. As in any battle, the tactics used by both sides change and adapt to situations. To study whiteflies, colonies are usually established from field infestations then maintained inside controlled-environment rooms within purpose built facilities. Specimens from all over the globe are often collected, allowing the researchers to keep up to date with the rapid evolution of the whitefly and plant viruses they can carry. These facilities, which often include high containment laboratories, enable researchers to study the development of the pests under tightly controlled situations, investigating the effects of new pesticides, natural enemies and physical barriers such as nettings. Some of the entomologists within EWSN have recently been using a range of microscopes from Vision Engineering to get close to the whitefly.

These include the Mantis low magnification viewer to study adult specimens on infected plants. The Mantis allows a clear, bright stereo image of the subject to be viewed by the operator. Because the Mantis has such a large working distance, objects can easily be manipulated underneath the viewer. This allows for an all round view of the plant samples, taking full advantage of the stereoscopic image. The whitefly are anaesthetised with CO2, preventing them from moving around the plant and allowing them to be counted and studied in more detail without killing them.

Also being used are the new Alpha and Beta stereo zoom microscopes. These microscopes are used for detailed study of individual adults and larval stages. Alpha uses an expanded pupil eyepiece, offering enhanced levels of comfort and efficiency for long term operator use. Researchers have commented that Alpha is a great microscope for extended use and is comfortable to use all day without any operator discomfort. A floating stage allows plant samples and dishes to be easily moved under these microscopes, maintaining a constant working distance. As with the Mantis, this working distance is large enough to allow the operator room for sample manipulation. Beta's conventional eyepieces provide an extremely cost effective solution for stereo viewing at mid-range magnification.

Both the Alpha and Beta stereo microscopes can be fitted with a camera attachment which connects to a conventional digital camera. This camera allows the researchers to display live video to a monitor as well as capturing high resolution images of the whitefly. These digital images can be captured immediately the researcher notices something of interest and can be rapidly included in reports or filed electronically for future viewing.

For further information on whiteflies, please visit the website of the European Whitefly Studies Network.