Tiny predator that's protecting the Christmas crop.Byline: Bill Mouland IF you haven't made a list yet or even thought about what to give who, look away now. As this sea of poinsettias shows, Christmas is just around the corner. In regulation rows, they stretch as far as the eye can see, the layers of leaves gradually turning from green to a festive scarlet. The 20,000 poinsettias in this picture - nurtured from seedlings imported from Germany - are a fraction of the 150,000 being grown for Sainsbury's at a nursery in West Sussex West Sussex, nonmetropolitan county (1991 pop. 692,800), 768 sq mi (1,990 sq km), S England. A chalk ridge runs from the county's east to west edge. In the south the land flattens into a gentle plain. After early Roman invasions, the Saxons moved across Sussex. . 'The trick is to grow them all to the same height and the same width and the same colour at the same time,' said David Loy Dr. David R. Loy (born 1947) currently holds the Besl Family Chair of Ethics/Religion & Society, a visiting appointment at Xavier University in Cincinnati, Ohio[1]. He received his Ph.D. in philosophy from the University of Singapore. , who manages Roundstone Nurseries near Chichester. Each poinsettia poinsettia: see spurge. poinsettia Popular flowering plant (Euphorbia pulcherrima), best-known member of the diverse spurge family. Native to Mexico and Central America, it grows in moist, wet, wooded ravines and on rocky hillsides. is planted in a 4in pot - first placed together with leaves touching and then moved apart so that they have room. The nursery has also employed a special weapon in the war on whitefly, the natural enemy of the poinsettia. It has enlisted hordes of a fierce predator from Essex - the 0.6mm parasite wasp - which lays its eggs in the white fly larvae Larvae, in Roman religion Larvae: see lemures. to destroy them. Two types of wasp are used: the encarsia formosa These tiny wasps are parasites of greenhouse whitefly. The tiny females (about 0.6 mm long) are black with a yellow abdomen and opalescent wings. Males are somewhat larger than females and completely black, and are extremely rare. , which attacks glasshouse whitefly, and its cousin eretmocerus erernicus, which kills tobacco plant whitefly. 'It's a bit like a scene from the film Alien,' said a spokesman from Syngenta Bioline, the firm that supplies the insects. 'The wasps lay their eggs in the whitefly and their larvae then feed on them. The whitefly turn black after about a week, and a wasp emerges by eating a hole in the surface of it.' That microscopic horror aside, it's a delightful 20c in the greenhouse, although this is gradually reduced to 15c as the day the plants are taken to be sold approaches. Nursery staff patrol the rows twice daily, making sure the plants are not too dry and pinching out shoots to make sure each one has a regulation six layers of leaves. They should be on the supermarket shelves in a matter of weeks. FACT FILE Five million poinsettias are sold every year in Britain, almost all in November and December The British market is worth [pounds sterling]25million annually Poinsettia pot plants are descended from a shrub which is native to Mexico. In the wild they can grow to 12ft They are named after the first U.S. ambassador to Mexico, botanist Joel Roberts Poinsettia, who found one growing by a road in 1828 They wilt instantly if exposed to temperatures below 50f CAPTION(S): On patrol: An encarsia formosa wasp The red mist: Poinsettias in the greenhouse |
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