Dr Abe V Rotor
Living with Nature - School on Blog [avrotor.blogspot.com]
Paaralang Bayan sa Himpapawid (People's School-on-Air) with Ms Melly C Tenorio
738 DZRB AM, [www.pbs.gov.ph] 8-9 evening class Monday to Friday
Are you looking for pesticides that are relatively safe to health and environment - that is, as compared with commercial chemical pesticides. Here are three locally growing plants in the tropic. Makabuhay (photo) is a perennial liana, neem is a small tree with pointed compound leaves, and botong is a large tree with broad leaves one may mistake it for talisay (Terminalia catappa).
Makabuhay and Neem tree extracts are effective in the control cockroach (Periplaneta Americana)
This is the finding of Tenorio RW, Nudo L, Roxas R and AC Uichanco from the UST Faculty of Pharmacy, based on the claims of old folks. Macabuhay (Tinospora rhumphii) is a liana that grows in the wild. Previous experiments proved that its extract is effective in controlling common rice insect pest and the golden kuhol.
Could it be effective in controlling the tough and elusive cockroach? The same question was raised on Neem (Aziderachta asiatica), known as insecticide tree that was introduced into the country from India in the sixties.
According to the researchers, extracts of both plants proved effective as direct spray on cockroach. Comparative effectiveness showed that the diluted extract of makabuhay gave a higher mortality that the pure extract, indicating the synergistic effect of water solvent, but only for makabuhay. Neem extract at low level dilution is more effective than that of makabuhay at the same level. While synthetic chemical sprays are more effective than these herbal extracts, the advantage of the latter is their being safe to humans and the environment and does not leave toxic residues.
Poison from the Seed of Botong (Barringtona asiatica) is used on rats.
If botong (Barringtona asiatica) is effective as fish poison, could it be effective as rat poison just as well? The researchers found it to be effective, but the problem to lure the rodents to eating the bait is a problem. This is because of the shy nature of rats and their oliphagous characteristic that is they eat a wide range of food under natural field condition. When starved rats may consume any available food and this may include poison baits. The advantage of using plant poison is its safe nature to humans and the environment. Presently used compounds include arsenicals, anticoagulants under the brand names Dethmor, Racumin, Dora, and the deadly “1081” a zinc phosphide compound which is now banned in the market. (Perez R, Dela Cruz K, Rivera M and J Santos, UST)
Nut-looking fruits of botong fall to the ground apon maturity. The fruit contains a large seed contains pesticidal properties. Fish poison is also derived from the seed of botong. This is the rational of an experiment: Is there a safer compound than synthetic pesticides to clean up fishponds in order to eliminate fish predators at seeding time? It is a known practice among fishpond owners to use Malathion, Endrin, and other chlorinated hydrocarbon, as well as phosphate compounds to eliminate fish such as tilapia, dalag, and Poecillia after harvesting a fishpond. These remaining fish pose danger as predator of bangus fries raised in the next season. The researchers found out that the extract of botong seeds (Barringtona asiatica) is an effective substitute. Like other plant extract, it is environment friendly and leaves non-toxic residue to the incoming fries and fingerlings. (Dequina MJ, Castro JC, Limtin R and J Patawaran, UST)
Closeup of neem (Aziderachta asiatica)Living with Nature, AVR
Crude extract from fresh mature leaves may be directly sprayed or watered to crops at varying dilution to control mostly common garden pest. Dried leaves placed under sleeping mat drive bedbugs and lice. Powdered dried leaves may are applied as dust in the garden to repel insects, land snail and slug.