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Control Number55740
Date and Time of Latest Transaction20120503221916.PM
General Information120503s |||||||||b ||00|||
Cataloging SourcePCARRD
Local Call NumberSB 608 S7 G37
Main Entry - Personal NameGaspar, Manuel G.
Title StatementInfluence of host plants and management practices on the populations of arthropod pests and natural enemies of soybeans (Glycine max L.) in corn-based agroecosystems in Cagayan Valley. Manuel G. Gaspar
Physical Description192 leves3
Summary, Etc.This study provides information and basic knowledge on the relative richness and abundance of arthropods and alternative sustainable management options for arthropods in corn-based agroecosystems of Cagayan Valley. The study was conducted in the riverflood plains of Ilagan, Isabela from October 1996 to October 1997. Effects of cropping systems (corn-corn, soybean-corn and corn soybean intercrop-corn cropping systems), fertilizer sources (unfertilized, poultry manure and recommended synthetic fertilizer source) and insect control methods (untreated, Helicoverpa armigera, nuclear polyhedrosis virus and recommended insect control methods) on arthropod populations, including herbivores natural enemies and soil arthropods, and crop productivity and profitability were compared. The influence of climate, soil quality and alternate hosts/habitat to arthropods' density were assessed. The abundant herbivores of corn were Atherigona oryza Malloch, Ostrinia furnacalis Guenee, Spodoptera spp. and Aphis craccivora Koch while soybeans were Empoasca sp., Cerotoma sp., Nezara viridula L, Spodoptera spp. and Homona coffearea. H. armigera was not considered a serious pest because of its low populations. The availability of alternate hosts contributed only a little to its population increase. The important natural enemies of corn and soybean herbivores were Menochilus sexmaculatus Fab. and Cyclosa insulana Copta, and araneid spider. The alternate habitats significantly increased the natural enemy populations. Twenty-one species of soil arthropods were extracted from soybean and cornfields. The most dominant was the detritivorous family Scheloribatidae consisting of three species. The wet season had relatively higher populations of arthropods than the dry season. Relative humidity (40-77%) and wind velocity (0.70-2.70 km/hour) were favorable to the populations of herbivores in the different cropping systems. The prolonged dry spell caused by uneven distribution of rainfall (2-132 mm/week) and air temperature (18.27?C) had negative effects. The recommended insect control practices for soybean and corn, which were chemical-based, decreased arthropod richness and densities. This was translated into yield advantage over untreated and HaNPV applied corn but not soybeans. However, such practices also reduced the densities of beneficial arthropods (natural enemies and soil arthropods) over the other treatments, which indicated the extent of disruption it caused to the agroecosystem stability especially in the long run. The synthetically fertilized plants had more abundant herbivores and natural enemies than the other fertilizer sources. However, this led to reduced richness of arthropods in general. Likewise, the soil applied with synthetic fertilizer was less favorable to the abundance of soil arthropods than poultry manure and unfertilized soils. The synthetically fertilized plants had higher yields in corn over the other fertilizer treatments, but not in soybeans. Corn soybean intercrop had higher species diversity (richness) of herbivores than the soybean and corn monocrop but not the species richness of other arthropods. In terms of abundance, soybean-corn and corn soybean intercrop-corn cropping systems had higher populations densities of arthropods than corn-corn cropping. The richness was associated with the species richness of crops. Soybean and corn had specialist herbivores, which contributed to the richness of the arthropods in soybean intercrop over the soybean and corn monocrop. Planting soybean, either as monocrop or intercrop without added fertilization and pesticide usage, therefore, was a more self-sustaining pest management strategy. This was because the cropping systems themselves enhanced natural enemy populations, which in turn would regulate herbivores. The soils in these cropping systems applied with the above management practices were conducive to soil arthropods that hasten decomposition of dead organic matter, which contributed to soil fertility and soil health. The contributions to soil fertility increased crop productivity and profitability.04
Subject Added Entry - Topical Termsoybeans, Glycine max04
 maize04
 corn -- pest control -- pests of plants -- Cagayan Valley04
 soybeans -- pest control -- pests of plants04
 arthropoda -- natural enemies
LocationDOST PCARRD SB 608 S7 G37 THESES PCARRD/SLS PCR-11-0034 1 Others 0000-00-00
  
     
 
Physical Location
Department of Science and Technology
Philippine Council for Agriculture, Forestry and Natural Resources Research and DevelopmentSB 608 S7 G37
  
     
 
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