Search results for "Crop"
showing 10 items of 3837 documents
Influence of biotic variables on invertebrate size structure and diversity in coastal wetlands of Southeastern Spain
2016
Abstract Biomass and size-based estimations provide relevant information regarding ecosystem functioning and biotic interactions. Our aims were to study the effect of fish and macrophytes on the size structure of invertebrate assemblages (from rotifers to insects) in a set of coastal water bodies, estimating the biomass (total and main invertebrate groups), the biomass-size spectra (model of Pareto) and size diversity. In fishless ponds, cladoceran and ostracod biomass were higher, and they presented greater size diversity. In fish ponds, rotifer biomass presented greater proportion; while in fishless ponds, cladocerans were usually the most abundant taxa and the largest organisms. The biom…
Response of zooplankton to nutrient enrichment and fish in shallow lakes: a pan-European mesocosm experiment
2004
1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 1999 by carrying out parallel mesocosm experiments in six lakes across Europe. 2. Zooplankton community structure, biomass and responses to nutrient and fish manipulation showed geographical and year-to-year differences. Fish had a greater influence than nutrients in regulating zooplankton biomass and especially the relative abundances of different functional groups of zooplankton. When fish reduced the biomass of large crustaceans, there was a complementary increase in the biomasses of smaller crustacean species and rotifers. 3. High abundance of submerged macrophytes provided refuge for zooplank…
Efficacy of sea fennel (Crithmum maritimum L., Apiaceae) essential oils against Culex quinquefasciatus Say and Spodoptera littoralis (Boisd.)
2017
The effective management of insect pests and vectors still represents a major challenge in current entomology. Culex quinquefasciatus Say is a key vector of lymphatic filariasis, Rift Valley fever, West Nile, St. Louis encephalitis and Western equine encephalitis virus. Recently, the importance of the eco-friendly control of C. quinquefasciatus larval population using plant-borne biopesticides, including essential oils (EOs), has been stressed. Spodoptera littoralis (Boisd.) also known as tobacco cutworm, is one of the most destructive moth agricultural pests in tropic and sub-tropic regions. Despite the fact that sea fennel (Crithmum maritimum L., Apiaceae) is considered as a promising bio…
Ectomycorrhizal fungi in wood-pastures : Communities are determined by trees and soil properties, not by grazing
2019
Traditional rural biotopes such as wood-pastures are species-rich environments that have been created by low-intensity agriculture. Their amount has decreased dramatically during the 20th century in whole Europe due to the intensification of agriculture. Wood-pastures host some fungal species that prefer warm areas and are adapted to semi-open conditions, but still very little is known about fungi in these habitats. We studied how management, historical land-use intensity, present grazing intensity, time since abandonment, and stand conditions affect the species richness and community composition of ectomycorrhizal fungi. We surveyed fruit bodies on three 10 m × 10 m study plots in 36 sites…
Genetic relationships between Sicilian wild populations of Brassica analysed with RAPD markers
2001
Brassica comprises very variable species, both morphologically and genetically. Among these species, the Sicilian populations of Brassica sect. Brassica, species related to kale crops form a complex group. The genetic relationships among 15 populations occurring in Sicily and one from Calabria, representing the existing diversity, have been investigated using random amplified polymorphic DNA (RAPD) markers. This assay, carried out with 22 arbitrary primers, generated 236 polymorphic fragments, 21 of which were specific for single populations (mainly Brassica insularis, Brassica incana and Brassica macro-carpa). Jaccard's genetic distances were computed and the phylogenic tree was establishe…
Biology and Behaviour of Cirrospilus diallus and Cirrospilus pictus, Parasitoids of Phyllocnistis citrella
2005
International audience; Studies were carried out on some biological and behavioral aspects of Cirrospilus diallus Walker and Cirrospilus pictus (Nees) (Hymenoptera: Eulophidae) in relation to their host, the citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Adults of both species fed with sugar lived on average 4.45 +/- 0.19 days, whereas adults provided with honey survived on average 40.62 +/- 1.97 days. Rates of host mortality due to parasitoid stings without oviposition were as high as 31.25 and 37.73% for C. pictus and C. diallus, respectively. Both species showed arrhenotokous parthenogenesis. Sex ratios of parasitoids emerging from the 2nd and 3rd …
The potential of nonpathogenic Fusarium oxysporum and other biological control organisms for suppressing fusarium wilt of banana
2006
Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; The aim of this study was to evaluate the ability of nonpathogenic F. oxysporum and Trichoderma isolates from suppressive soils in South Africa to suppress fusarium wilt of banana in the glasshouse. Several biological control agents and commercial biological control products were included in the study. The isolates were first screened in vitro on potato dextrose agar. In glasshouse evaluations, the fungal and bacterial isolates were established on banana roots before they were repla…
Defoliation of two-wire vertical trellis: effect on grape quality
2017
ABSTRACTBasal leaves were removed from Cabernet Sauvignon vines trained to a two-wire vertical trellis at fruit set and at veraison. Leaf removal did not modify total soluble solids and titratable acidity at harvest. Defoliation at fruit set of lower cordon recovered the grape anthocyanin composition gap between upper and lower cordons and that produced a positive effect on anthocyanin synthesis. Hence, control of the upper cordon and defoliation of fruit set of the lower cordon treatments showed comparable values of anthocyanins. Defoliation at veraison did not produce any appreciable effect. This study shows that skin anthocyanin composition in a two-wire vertical trellis can be modified …
The Effect of Soil Volume Availability on Opuntia ficus-indica Canopy and Root Growth
2020
The study investigated the effect of soil volume restriction on the below- and above-ground growth of Opuntia ficus-indica through understanding the limit imposed by root confinement via different soil volumes on root and canopy architecture and growth. In 2014, one-year-old O. ficus-indica cladodes were planted in five different soil volumes (50, 33, 18, 9 and 5 L). The cladode and roots of each sampled plants were measured and weighed every six months
Behaviour of alkyl oleates following foliar application in relation to their influence on the penetration of phenmedipham and quizalofop-P-ethyl
1997
Summary The foliar penetration of four alkyl oleates (methyl to butyl) and their influence on the penetration of phenmedipham and quizalofop-P-ethyl was studied in barley (Hordeum vulgare L.), cleavers (Galium aparine L.) and pea (Pisum sativum L.). Loss of alkyl oleates from glass and plant surfaces was inversely related to the length of the alkyl chains and was assumed to be due to volatilization. All four alkyl oleates after application alone, readily penetrated into pea and barley leaves but much less into G. aparine. Penetration of methyl oleate appeared to be faster than that of butyl oleate. Both alkyl oleates were completely metabolized in barley and pea in 27 h, but not in G. apari…