Going Green with Biopesticides

By Dr. Rafael D. Guerrero III

Crop production in agriculture requires effective control of plant pathogens, weeds, and invertebrates like insects that can reduce yields up to 50%. There are about 67,000 species of plant pests. The conventional pesticides (compounds for controlling pests) used contain chemicals that are not only toxic to target species but can also be toxic to beneficial organisms and persist in the environment for a long time. Biopesticides (biological pesticides) that are produced from natural materials from animals, plants, bacteria, and minerals are an alternative to chemical pesticides.

Biopesticides are classified into: microbial (e.g., bacteria and fungi); biochemical (e.g., pyrethrins); and plant-incorporated protectants (PIPs) such as the sulfur in onion and allicin in garlic. Organic pesticides have the advantage of being less toxic than chemicals; are biodegradable; are easier and cheaper to produce; are highly specific in effect; and do not persist long in the environment. Their disadvantage is that they work slowly and can have variable efficacy. According to the Biopesticide Industry Alliance (www.bpia.org/history-ofbiopesticides/), biopesticides inhibit “…the growth, feeding, development or reproduction of a pest or pathogen.”

In field trials conducted on two biopesticides—fermented fruit juice (FFJ) and lactic acid-based
pesticide (LAP)—by researchers of the Department of Agriculture’s (DA) Regional Field Office in the Cagayan Valley headed by Executive Director Lucrecio Alavar, Jr., it was found that the FFJ controlled 9-32% of rice insect pests (leaf hopper and leaf folder) while the LAP was 50% effective against the bacterial leaf blight of rice. The yields of rice sprayed 3-5 times with FFJ and 2-5 times with LAP were 6% and 14%, respectively, more than the yield of unsprayed rice. The returns on investment (ROI) on crops grown using the biopesticides were 7-15% more than those grown without their use. 

The DA researchers recommend the following for making and using FFJ for one hectare:
(1) Grind or blend 100 grams of red onion, 100 grams of garlic, and 100 grams of siling labuyo in 200 milliliters (ml) or 0.2 liter of water.
(2) Add 0.8 liters of water to the prepared mixture and store in a closed plastic or glass container for 2-3 days in a cool, dry place.
(3) Before using in the field, stir the fermented juice and filter the solution with a fine mesh cloth to avoid clogging the sprayer.
(4) Use 20-30 ml of FFJ per liter of water for spraying. A hectare will need 3.68 liters of FFJ.

(Note: Cover mouth and nose when spraying to prevent irritation of the eyes and skin.)

The procedure for making and using LAP are:
(1) Wash a cup of rice thoroughly with two cups of water.
(2) Decant the rice water and keep this in a container with half of the space empty, to allow for air. Cover with a paper towel or cloth and keep at room temperature away from direct sunlight for 1-2 weeks.
(3) When the rice wash smells acidic with fermentation, mix 0.1 liters of it with one liter of milk. Cover the container with mesh cloth for 7-10 days or until a ‘cheesy’ layer forms on the surface.
(4) Remove cheesy layer and set aside. Filter the liquid with a cheesecloth and keep in a tightly sealed container in the refrigerator for up to one year. Without a refrigerator, mix the liquid with molasses or brown sugar with a 1:1 ratio by weight. This mother stock solution can stay for three years.
(5) To prepare the base solution, use one part of the mother stock solution with 20 parts of water. This mixture can stay active for six months without refrigeration.
(6) When spraying, use one tablespoon of the base solution for every liter of water.

This appeared in Agriculture Monthly’s August 2016 issue.