Biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal applications and are considered biopesticides. At the end of 2001, there were approximately 195 registered biopesticide active ingredients and 780 products.
The use of commercial pesticides kill, not only the target insect pests, but also beneficial insects like spiders, grasshoppers and others. Besides this, it leaves residues in the plant where it is sprayed, and is harmful to the person spraying. If inhaled, pesticides can cause cancer in the long run.
Biopesticides fall into three major classes:
1. Microbial pesticides consist of a microorganism (e.g., a bacterium, fungus, virus or protozoan) as the active ingredient. Microbial pesticides can control many different kinds of pests, although each separate active ingredient is relatively specific for its target pest[s]. For example, there are fungi that control certain weeds, and other fungi that kill specific insects.
The most widely used microbial pesticides are subspecies and strains of Bacillus thuringiensis, or Bt. Each strain of this bacterium produces a different mix of proteins, and specifically kills one or a few related species of insect larvae. While some Bt’s control moth larvae found on plants, other Bt’s are specific for larvae of flies and mosquitoes. The target insect species are determined by whether the particular Bt produces a protein that can bind to a larval gut receptor, thereby causing the insect larvae to starve.
2. Plant-Incorporated-Protectants (PIPs) are pesticidal substances that plants produce from genetic material that has been added to the plant. For example, scientists can take the gene for the Bt pesticidal protein, and introduce the gene into the plant’s own genetic material. Then the plant, instead of the Bt bacterium, manufactures the substance that destroys the pest. The protein and its genetic material, but not the plant itself, are regulated by EPA.
3. Biochemical pesticides are naturally occurring substances that control pests by non-toxic mechanisms. Conventional pesticides, by contrast, are generally synthetic materials that directly kill or inactivate the pest. Biochemical pesticides include substances, such as insect sex pheromones, that interfere with mating, as well as various scented plant extracts that attract insect pests to traps. Because it is sometimes difficult to determine whether a substance meets the criteria for classification as a biochemical pesticide, EPA has established a special committee to make such decisions.
What are the advantages of using biopesticides?
- Biopesticides are usually inherently less toxic than conventional pesticides.
- Biopesticides generally affect only the target pest and closely related organisms, in contrast to broad spectrum, conventional pesticides that may affect organisms as different as birds, insects, and mammals.
- Biopesticides often are effective in very small quantities and often decompose quickly, thereby resulting in lower exposures and largely avoiding the pollution problems caused by conventional pesticides.
- When used as a component of Integrated Pest Management (IPM) programs, biopesticides can greatly decrease the use of conventional pesticides, while crop yields remain high.
- To use biopesticides effectively, however, users need to know a great deal about managing pests.
Pesticides chemically prepared are expensive; we have plants that naturally repel harmful insects at no cost, such as:
- Wild pepper (dried and pulverized) — spray on infected plants. When this becomes moist from dew, insect pests are repelled.
- Combination of 3 pieces garlic, 2 pieces pepper, and 2 pieces onions grind and pulverize these, soak overnight in water. By next morning, fill up the water to make 3 gallons. Strain and spray on affected plants.
- Ash and lime: spread around the plants to keep off snails or land leeches, put a basin of water beside the plant to attract and trap the snails
- Essence (oil) from oranges, calamansi, pomelo and other citrus — dispels and kills ants, flies, white crickets, etc.
- Damong Maria (dried) — when burned drives away insect pests
- Eucalyptus leaves
- Manzanilla flowers
Is a kind of white chrysanthemum that grows in high altitudes like the Mountain Province. It contains pyrethrin, a chemical, that drives insects away. The higher the altitude, the stronger is its pyrethrin content. The pyrethrin or pesticide content of this flower is not harmful to humans, and is beneficial to plants like potatoes. It also repels insect pests that feed on cultured plants. Pyrethrin comes from chrysanthemum leaves.
Marigold or amarillo contains a chemical that is toxic to some pests in the soil, like nematodes. Thus, it is good to plant marigold together with vegetables or in between farm crops. Nematodes are very tiny parasites or worms in the soil, river, sea, rotting wood or plants. They also thrive in other parts of the plant like the roots, and in animals and insects. Most nematodes are not harmful, but even helpful in fertilizing the soil. However, their danger lies in that they feed on roots, stems, or leaves of plants — they suck the nutrients.
Kalingag – Insect Repellant
The most damaging insect pest that preys on fruits is the fruit fly. Once it gets into the flesh of any fruit, it can reproduce and spread wherever that fruit may be brought. Thus, in efforts of importing countries to avoid the entrance of this pest into their territories, strict regulations are imposed on incoming fruits for instance our mango.
It was found out by a scientist from the Bureau of Plant Industry in Quezon that the bark of the Kalingag attracts, insects, especially the fruit fly, thus facilitates their entrapment.
- Pulverize the bark of the kalingag tree.
- Mix the powder in 2% water solution that is, 2 grams per liter of water.
- Put this in containers with traps.
The fruit flies will approach it, especially early in the morning and late afternoon.
Makabuhay (Tubli) – Excellent Source of Insecticides
In a research conducted by the Philippine Council for Agriculture, Forestry and Natural Resources Research & Development (PCARRD) at the U.P. Los BaÃƒÂ±os, it was found out that the juice of 50 grams of makabuhay for 1.25 liters water can control rice green leafhoppers, insects that bring the virus of the disease in palay.
There are various ways of using makabuhay. One is by soaking the roots of the palay seedlings in the makabuhay solution 24 hours before planting. Another is by broadcasting the juice of the makabuhay on the palay seedlings.
The effect of these is almost the same as that of carbofuran, a chemical insecticide against leafhoppers.
Two kilograms of ground makabuhay can also be broadcast in a square meter of field 10 days after plowing. This is the same as broadcasting carbofuran which is effective 5-7 days after application. Besides its use as insecticide, makabuhay is also used in the relief of stomachache, indigestion, diarrhea, ulcer, parasites and malaria.
source: www.dost.gov.ph, www.da.gov.ph, www.epa.gov, photo from vmsrf.org