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已出版: 1993-10-19


ECHO's name symbolizes ideas, information and seeds "echoing" back and forth between ourselves and our overseas network.  We owe much of our effectiveness to you.  There are many examples in this issue.  The most difficult editing decision is always which material to delay.  We have enough material to print many issues of EDN.  The information you send may or may not make it "into print," but be assured that we have made use of it internally and greatly appreciate your calling it to our attention

Roland Lesseps, S. J., Zambia.  "Termites here make it very difficult to establish tree seedlings in the field.  In some places at Kasisi we have lost about 90% of our Leucaena leucocephala seedlings.  So we are always on the lookout for a tree that is termite resistant.  An excellent one is Senna (Cassia) siamea.  We planted four rows four years ago (about 70 trees per row) in a field terribly infested with termites.  Almost all the trees are alive and growing luxuriantly.  We have coppiced them three times and used the leaves in compost piles.  The cut branches make good poles or firewood.  We earlier fed the leaves to cattle, then we heard at an ICRAF meeting that the leaves, though eaten by goats, are not good for cattle."

TEPHROSIA VOGELII FOR GREEN MANURE AND INSECT CONTROL.  Three members of our network recently wrote us about the same plant for different reasons. 

Beth Adams writes from Malawi, "I planted several rows of leucaena trees on the edges of terraces, for green manure and erosion control.  They are doing well and beginning to flower.  I've found a shrub that seems to be much better though, fish bean or Tephrosia vogelii.  It produces an incredible amount of leaf matter, grows very quickly, and is very easy to establish..  I planted them about 2 feet apart and now, 7 months later, they are almost a solid wall.  They are not used as fodder."

"I have been very impressed with fish bean as an insecticide.  Some of my students told me they had used the leaves to kill caterpillars, so we tried it.  It killed every caterpillar overnight.  It was incredible since most natural insecticides don't seem to work that quickly.  We did an experiment on an okra crop that was full of aphids using Malathion, tephrosia bean extract, soap (1 teaspoon per liter) and a tephrosia/soap mixture.  The latter had the best results, tephrosia and Malathion were about the same, and soap was least effective.  We've not been able to use neem because the trees planted in 1992 keep dying back and then regrowing.  So I am encouraging students to plant tephrosia since it is much easier to establish here and can be used as a green manure as well.

Emmanuel Soko in Tanzania is an extensionist working with Fr. Rupper, who has frequently written and shared seeds.  Emmanuel shared how tephrosia is used for insect control in grain storage.  "Take fresh leaves and dry them under the sun.  Grind the dried leaves into a powder.  Mix 100 grams of powder with 100 kg of maize to control maize weevils and the larger grain boer; with 100 kg of beans to control the bean bruchids.  The chemical is effective up to three months.  After that time the process must be repeated. 

The plant has many other uses. 

"To control ticks, lice and flies, animals (cattle, sheep, goats, pets) are washed with the extract of the plant.  To make the extract, fresh leaves and branches are pounded in a mortar.  This is diluted with five times that volume of water before applying to the animals.  

"To make an insecticide, allow the above mixture to soak overnight or boil it for 30 minutes.  Add a bit of soap to help the spray stick to the leaves.  It can be used with garden vegetables, fruits and field crops, to control termites, ants, beetles, aphids, cutworms, various bugs and weevils, stalk boers, flies etc. 

"In the evening the walls of the room, especially corners, are beaten with fresh branches to repel mosquitoes, lice, ticks, cockroaches, etc.  It is fed to animals for intestinal problems.  "

Roland Lesseps sent a copy of a fact sheet written by his colleague Andy McDavid at the Kasisi Agricultural Training Center in Zambia, from which a few excerpts follow.

"It has been used as a fish poison for hundreds of years and an insecticide for over a hundred."  "Cattle deaths have been reported as a result of drinking water of poisoned fish ponds.  Also, reports have been made from one village of people getting sick after eating fish poisoned with the extract.  I do not advise its use as a fish poison.

"The shrub may grow as rapidly as 2-3 meters in 7 months.  The compound leaves contain the highest concentration of rotenoids, which are responsible for its insecticidal effectiveness.  ...Its compounds are effective against a number of different pests (tested at least 90% effective against termites, citrus aphids, red spider mites).  They break down in about 7 days (2-3 days in bright sunlight)."  Seeds should "be soaked in water for about 24 hours for good germination (about 90%).  Plant about 1 meter apart."  If very large numbers are planted, use 35,000 seeds per ha for greatest leaf yield. 

"In harvesting, only the leaves need to be taken off the shrub.  ... If removed carefully, the shrub will continue to produce leaves for ... extract or mulch.  The most effective concentration for killing insects was found to be 20 g of leaves for every 100 ml of water.  If a scale is not available, take the amount of leaves equal to the weight of an empty 300 ml coke bottle, then add 7 coke bottles full of water.  ...The crushing of leaves does not need to be done perfectly; a plastic feed bag and large rock can be used."  After soaking for 2 hours (NOT in direct sunlight) filter the suspension through a cloth and use directly in the sprayer. 

"It is important that the spray have contact with the pest.  If the pest is underneath the leaves, be sure to actually hit the pests.  ...If all the spray is not used immediately, it will still be approximately 70% effective 24 hours later, IF kept out of direct sunlight."  Beyond that its potency drops quickly.  The "used" leaves may be reused for a second extract.  Tests have not determined concentrations to use but have shown that effective chemicals are left.  "The leaves contain an antifeedant, so termites will not eat it.  In areas of heavy termite infestation this mulch can be very helpful."