Published on January 7, 2008
Slide1: MINIMIZING OFF-SITE IMPACT OF PESTICIDES FROM AGRICULTURAL SYSTEMS - A RISK BASED APPROACH Slide2: PROJECT SITES AND CROP PROTECTION MANAGEMENT OF FARMERS WITHIN THE PROJECT AREAS L. E. FABRO, G.A. PERALTA, L. M. VARCA, C. M. BAJET, MF. P. NAVARRO & B. B. QUINTANA Slide3: Laguna Lake Slide4: This is the largest body of fresh water in the Philippines. It has a surface area of about 90,000 hectares with an average depth of 2.8 meters. It contains roughly 3.2 B m3 of water and a shoreline of 220 km. Some 21 tributaries drain into the lake. Slide5: Uses of the lakes and its major tributaries Uses of the lake and its major tributaries takes in the form of consumptive and non-consumptive uses. Consumptive uses are consumption of water without necessarily returning it back to its sources. Water is either absorbed by the soil or form parts of the wastewater discharge. This includes irrigation and domestic consumption. Rice and vegetable farmer-irrigators use up to 405.21 m3/year while domestic water users spend about 52.5 million m3/year. Ayala Land Inc. draws from the lake drinking water for its concessionaires and clients in their real estate business. Non-consumptive users plowed back water to its source with minimal or negligible change in quantity and quality. Petroleum industries located near the lake extract water to cool their machineries. The National Power Corporation passed through its turbines about 527.04 M m3 to generate electricity. Slide12: Five (5) towns in the province of Laguna were chosen namely, Lumban, Pagsanjan, Liliw, Calauan and Bay. Specific rivers for each town were monitored for the presence of pesticides in both water and sediments. Three (3) sampling sites were identified for each river and designated as upstream, midstream and downstream. Distance between sampling points ranged from about 100 to 1000 m. However, sites for downstream were close or at the edge of the lake. Project Sites Slide20: Rice farmers of Lumban, Pagsanjan and Bay used several pesticides in their farming system. Based from survey and interview, pesticides used were herbicides ( pre and post-emergence) , insecticides, molluscicides and a little of fungicides. Herbicides include butachlor, pretilachlor, piperophos, 2,4-D and some other ready- to- use combination (RTU). Popular insecticides were the pyrethroids such as cypermethrin, deltamethrin, -cyhalothrin and other carbamates and organophosphate insecticides were also commonly used. Molluscicides were that of niclosamide and metaldehyde. Farmer’s Pesticide Management Practices Slide24: Vegetable farmers of Liliw and Lumban used mainly insecticides, fungicides and foliar fertilizers to ensure high and good quality harvest. Bittergourd (ampalaya) received insecticide spray two weeks after planting. Frequency of insecticide application increased towards fruiting stage. Spraying of insecticides and fungicides plus foliar fertilizer is done every 4 to 5 days. This is after every harvest. Farmer’s Pesticide Management Practices Slide25: Pyrethroids such as cypermethrin and deltamethrin are the most commonly used compounds although some usage of methamidophos, profenophos and chlorpyrifos were also noted. Monitoring of pesticide residue from pineapple was made in Calauan. Diuron was used by all farmers interviewed while some indicated using fluazifop-butyl. Minimal to no insecticide application was learned from the farmers. Pineapple planted in between rows of rambutan are not the direct recipient of insecticide spray made on rambutan especially during the reproductive stage of the fruit trees. Commonly used insecticides on rambutan were the pyrethroid compounds. Farmer’s Pesticide Management Practices Slide26: Taal Lake Slide29: This is the second largest fresh water body in the country. It has an area of about 127 km2 wherein 23 km2 is occupied by the volcano island. It is the world’s lowest volcano with about 200 m of the deepest portion. It has 47 craters but only nine of them are presently active. Water is supplied by permanent and intermittent streams and rivers. Taal Lake Slide30: Uses of the lake and its tributaries include fish production, irrigation, domestic use such as washing , drinking and eco-tourism to mention a few. The Tagaytay Highlands Golf and Country Club draws water from the lake for drinking and irrigation needs on its golf courses. Uses of the Lake and Its Tributaries Slide36: Project Sites Towns of Laurel and Talisay were chosen wherein rice/vegetables and fish hatcheries and plant nurseries were the main agroecosystems, respectively. Slide40: Results of the survey on pesticide used in Laurel revealed that rice farmers do not use much of pesticides today because of possible toxic effect on fish fingerlings that are raised in ponds as well as those that are grown in fish cages in the lake. Although use of butachlor has been indicated, very few farmers are involved. The use of 2,4-D in rice has been mentioned but this was prior to the establishment of fish ponds. This period was about ten years ago. The use of molluscicide in fish ponds prior to stocking is common. In some areas nearer the foot of the mountain, vegetable growers used insecticides as well as those planted along the rice paddy dikes. Pyrethroid compounds were the most commonly used insecticides. Slide43: In Talisay where plant nurseries abound, insecticide application was high. Farmers and plant propagators start to apply insecticides as soon as the young leaves of the scions start to emerge. Spraying two to three times per week on the young grafted seedling is made just to protect them from leaf damaging insects. This is so because the price of the seedlings depend on the appearance of the whole plant especially the leaves. Pyrethroid compounds are the most popular insecticides used by the farmers.