Leucaena under attack
Long considered virtually pest-free, leucaena is succumbing to a small bug from Cuba. The psyllid insect, Heteropsylla cubana is a small plant louse resembling a miniature cicada. It spreads both by jumping and by riding in high altitude air currents. It was first reported in Florida in 1983 and spread westwards via the Pacific, Philippines, Indonesia, Papua New Guinea Australia and Malaysia to Thailand. India, and then Africa, may be next. The pest is devastating in its effect on leucaena trees and causes widespread defoliation. Adults and nymphs feed on old and new growth but it is the nymphs that do most damage: although they consume only the young shoots, the nymphs excrete a sticky fluid which prevents the development of remaining foliage. Nymphs may also carry toxins in their saliva, which are injected when feeding. Trees infested with psyllids are more susceptible to disease if they are under drought stress or are heavily pruned and may die, especially if they are only a year or two old. Chemical control measures have not proved effective so far and scientists are looking at biological control agents: one is a ladybird beetle, the psyllid's main predator in Hawaii, and certain wasps are parasitic on Heteropsylla. However, since introducing exotic predators is risky, national efforts in several countries are focused on finding local predators, control by fungal pathogens is also a possibility. For more details, contact: Dr Jeffrey Waage CIBC Imperial College at Ascot Berks SL5 7PY UK or Leucaena Research Reports Nitrogen Fixing Tree Association PO Box 680 Waimanalo Hawaii 96795 USA
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| Format: | News Item biblioteca |
| Language: | English |
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Technical Centre for Agricultural and Rural Cooperation
1988
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| Online Access: | https://hdl.handle.net/10568/44882 http://collections.infocollections.org/ukedu/en/d/Jcta16e/ |
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