Evaluation of Various Botanical Insecticides to Control Insect Pests of Pechay ( Brassica chinensis )
Introduction :
Many plants and minerals have insecticidal properties which are toxic to insects. Botanical insecticides are naturally occurring chemicals (insect toxins) extracted or derived from plants or animals. They also called natural insecticides.http://landscapeipm.tamu.edu/types-of-pest-control/chemical-control/organic/botanical/
As a response to such health concerns, the use of botanical pesticides is now fast gaining wider acceptance among farmers.Eric Vinje of Planet Natural wrote that natural pest controls like the botanicals are safer to the user and the environment because they break down into harmless compounds within hours or days in the presence of sunlight. According to Gaby Stoll a german agrobiologist and author of Natural Crop Protection that botanical pesticides is one answer to the pest problem in developing countries, He also says the move from chemical to botanical pesticides is, an important step in the search for a balanced, self-regulating agricultural system.”http://www.gaiadiscovery.com/agriculture-industry/organic-botanical-pesticides-cheaper-effective-pest-control.html
Botanical insecticides are derived from plants which have been shown to have insecticidal properties. Natural pest controls like the botanicals are safer to the user and the environment because they break down into harmless compounds within hours or days in the presence of sunlight and relatively safe form of pest in most cases (Magday , 2013)
Botanical pesticides have the following outstanding advantages: first, because they contain the active ingredients are natural substances, instead of synthetic chemicals, after application of the degradation of nature has its way smoothly, environmental pollution or pollution; second , due to larger proportion of plant pesticides insecticide, a unique mode of action, resistance to pests is more difficult; third, they generally have a selectivity of people, animals and natural enemies of low toxicity, the development and use of relatively low-cost characteristics. http://resources.alibaba.com/topic/800113046/Advantages_and_disadvantages_of_plant_pesticides.htm
Reliance on synthetic chemicals to control pests has also given rise to a number of problems such as destruction of beneficial non-target organisms (parasitoids and predators) thereby affecting the food chain and impacting on biological diversity.The injudicious use of synthetic pesticides can lead to secondary outbreaks of pests that are normally under natural control resulting in their rapid proliferation. As well as they are expensive in the market nowadays and poisonous to some forms of life. (http://ARC_Efficacyofthebotanicalpesticide.pdf)
In 2006, pechay contributed around P1.08B to the local economy.generally grown in the high and mid-elevation areas although it can also be grown in the low elevation during the cool dry months of November to February the popular variety type in CAR is the barrel type while in the southern Philippines the michihili type is preferred.organic pechay is being produced in limited quantities production was 37,171 t in 2006, up by 0.30% from the output of the previous year at 37,062 t major producer was the Cordillera Administrative Region (89.4%)area harvested in 2006 was 3,444 ha, up by 10% from 3,133 ha in 2005 yield per hectare was 9.05 t in 2006, 23.5% lower than the 11.8 t posted in 2005 http://www.pcaarrd.dost.gov.ph/home/joomla/index.php?option=com_content&task=view&id=828&Itemid=582.
Review of literature:
Pechay ( Brassica chinensis ) also known as leafy Chinese cabbage, is one of the popular vegetable in mainland China, Philippines, Vietnam and other East-Asian regions. At the same time, this humble Brassica family leafy-vegetable has captured attention of the western world for its sweet, succulent nutritious leaves and stalks. It is also recognized by several local dialects in the East Asian countries as pe-tsai, pak choi, petsay, white-celery mustard, Chinese white cabbage. The leaves of the pechay vary in length from 10 to 30 cm. The leaves are green and mild flavored and less crisp than other cabbages. It is often used in stews and soups.
Pechay is a shallow rooted plant that requires loose, highly fertile , and well drained soil for its growth and development. A light and loamy soil with high moisture retention is recommended for pechay. It needs additional supply to supplement nutrients for plants ( Sagarino, 2009 ).
Certain butterflies and moths (Lepidoptera spp.) lay their eggs on pechay, where the eggs hatch into leaf-feeding caterpillars. Aphids colonize pechay, where they suck juices from the leaves and exude honeydew, which can result in a sooty black mold on leaves. Leafminers (Liriomyza sativae and Liriomyza trifolii) puncture holes in pechay leaves and lay their eggs, where the larvae feed between the upper and lower leaf surfaces, creating a tunnel in the leaf. Flea beetles (Phyllotreta spp.) are hard-shelled insects that chew holes in leaves. http://homeguides.sfgate.com/pesticides-used-pechay-101245.html
Chili pepper ( Capsicum frutescens ) are high in vitamin A and C, but low in calories and sodium. Chilies contain potassium, magnesium and folic acid. But capsaicinoids are responsible for the pungency and are considered as active compounds in chilies. Capsaicin accounts for about 50 to 70% of the total capsaicinoids. In contrast, many studies reveal substantial antioxidant, antigenotoxic and anticarcinogenic effects of chili extracts and capsaicin .http://scholarsrese(htarchlibrary.com/archive.html)
The spiciness is a defense mechanism that some peppers develop to suppress a microbial fungus that invades through punctures made in the outer skin by insects. The fungus, from a large genus called Fusarium, destroys the plant's seeds before they can be eaten by birds and widely distributed.However, the researchers found that the pungency, or heat, in hot chilies acts as a unique defense mechanism. The pungency comes from capsaicinoids, the same chemicals that protect them from fungal attack by dramatically slowing microbial growth. https://www.sciencedaily.com/releases..html
Makabuhai ( Tinospora rumphii Boerl ) , on the other hand, belongs to the family of menispermepemia. This can grow or climb up to fifteen meters long. The leaves are thin sheets and heart-shaped, flowers are numerous , bisexual and have three petals. This plant may propagated by planting its stem . This stem contains fixed oil, 33% ; with triolein 87.7%, triplamitin 8.41%, tristearin 3.89%, a glycoside and samaderin. There are also traces of 2.22% columbine, picroretine, berberine and an alkaloid that can kill insects like blackbug rice, green green leafhopper, rice stemborer, leafhopper and rice stemborer .
Neem Tree ( Azadirachta indica ) is a tree in the mahogany family Meliaceae. It is one of two species in the genus Azadirachta, and is native to India. Its fruits and seeds are the source of neem oil.The neem tree is noted for its drought resistance. Neem trees are grown commercially in plantations to produce azadirachtin, a chemical extracted from the seeds and leaves. Azadirachtin has been promoted as a new insecticide that is considered more ‘environmentally friendly’ than synthetic insecticides. ( http://IPA-NEEM-TREE-ASSESSMENT.pdf )
Each botanicals killed pests like diamondback moth, rice blackbug ,rice green leafhopper, rice stemborer, leafhopper and rice stemborer in Makabuhai.Chili peppers killed pests ants, aphids, caterpillars ,flies and mealybugs. Neem leaves killed pests like ants, aphids, caterpillars, flies and mealybugs.
Objectives:
The study will be conducted to determine the most effective in botanical insecticides against pest of pechay .
Materials and Methods
Materials
The materials that will be used in this study are the following : pechay seeds , polyethylene plastic pot, sandy-loam soil, makabuhai stem extract, chili pepper extract, neem tree leaves extract and other important materials.
Methods
Experimental Design and Treatments. A Completely Randomized Design (CRD) will be used in study with (4) treatments and (5) replications.
The treatments to be used are the following :
T1 - Control ( water only )
T2 - Chili Pepper extract ( Capsicum frutescens )
T3 - Makabuhai stem extract ( Tinospora rumphii Boerl )
T4 - Neem leaves ( Azadirachta indica )
Preparation of the concoction.
Makabuhay Stem Extract
Cut the Makabuhai stem using knife . Collect before sunrise and avoid collecting after excessive rain. Chop into small vines and pound it thoroughly using mortal and pestle. Weigh up to 200 grams of chops makabuhay stem and add 1 liter of water . Stir with bamboo or wooden stick.
Chili Pepper Extract
Prepare 4 cups of ripe hot peppers or 5 cups of chili seeds. In a pot, boil ripe pods or chili seeds in water for 15-20 minutes . Take the pot from the fire and add 3 liters of water. Let the concoction cool in a couple of minutes . After cooling, filter the materials. Add 30 grams of soap in a concoction and stir well.
Neem Leaf Extract
Collect fresh neem leaves using knife.Mash the neem leaves in the mortar and pestle then place the mashed neem leaves in the container or pot. Add the water and cover the container/pot with a lid. Allow the mixture to steep for at least three days. After 3 days use the strainer to remove the leaves from the mixture. The liquid or extract should be clear. Dilute one-half or 1 L of the liquid with approximately 8 L of water in another container, then add the liquid soap. Pour the mixture into a spray bottle. Store the extract in a dark bottle in the refrigerator.
POTTING MATERIALS: The potting materials will be using a polyethylene bag and soil will be prepared by gathering top soil as potting soil and each pot will be weighed ten kilograms. PLANTING: WEEDING AND CULTIVATION: Potted soil will be cultivated after the plants have established vegetative growth by putting the soil towards to the sides of the plants. This will be followed by hand weeding to remove the weeds within the pot of the plants.
PEST AND DISEASE MANAGEMENT: Disease development will monitored for the duration of the entire study to control pathogens that may attack the crop.Proper pest and disease management was implemented until the plants were ready for harvesting.
IRRIGATION:Watering will be done daily to maintain proper soil moisture. FERTILIZATION: Fertilization will be done in all treatments during planting and side-dressing 15 days after planting (DAP) .
HARVESTING: Harvesting will be done manually when the pechay reach physiological maturity.
