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Beet Fields (beet + field)
Kinds of Beet Fields Selected AbstractsSpatio-temporal pattern of Pentastiridius leporinus migration in an ephemeral cropping systemAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2010Alberto Bressan 1Cixiid planthoppers (Hemiptera: Fulgoromorpha: Cixiidae) are considered to be important economic pests because of their ability to transmit phloem-restricted prokaryotes causing emerging plant diseases worldwide. However, little information is available on the biology and ecology of such species. This is the case for Pentastiridius leporinus (Linnaeus), a cixiid planthopper reported to live on common reed across Countries of Central and Northern Europe. However, in the east of France, the same planthopper species appears to complete its life cycle in the sugar beet-wheat cropping system and has been repeatedly shown to transmit prokaryotic plant pathogens that are associated with an emerging disease of sugar beet called syndrome ,basses richesses'. 2To gather evidence on the biology of the planthopper in the cropping rotation, we analysed the flight activity of adults. We used transparent sticky traps for sampling migrating adults and quantified nymphs as well as emerging adults on the roots of wheat plants. 3Results showed a significant correlation between disappearance of nymphs and emerging adults from wheat roots and the occurrence of migrant adults in nearby sugar beet fields. Planthoppers migrated more abundantly and colonized sugar beet for longer periods than any other crop available. Flight activity was very pronounced during the migratory phase that was extended from the middle of June to the middle of July. A geographic information system and geostatical analysis revealed that planthoppers flew and colonized the centre of the sugar beet field rather than the borders. 4Overall, results obtained in the present study suggest that the ecology and biology of the planthopper vector in the cropping rotation is a primary factor that leads to the emergence of the syndrome ,basses richesses' disease of sugar beet. [source] Transgenic weed beets: possible, probable, avoidable?JOURNAL OF APPLIED ECOLOGY, Issue 4 2002Benoît Desplanque Summary 1Weed beets pose a serious problem for sugar beet Beta vulgaris crops. Traditionally, the only efficient method of weed control has been manual removal, but the introduction of transgenic herbicide-tolerant sugar beets may provide an alternative solution because non-tolerant weed beets can be destroyed by herbicide. We evaluated the possibility that new, transgenic, weed beets may arise by gene flow between wild and crop plants. 2In a study area in northern France, weed beets were present in variable densities in sugar beet fields of up to 80 weed beet plants m,2. Weed beets arise from a long-lived seed bank, with seeds germinating from depths of 5 cm or less. In addition, diploid F1 crop,wild hybrids and triploid variety bolters (individuals with a low vernalization requirement) were present in low densities in virtually all sugar beet fields. We found gene flow to be possible between all forms, illustrated by both overlapping flowering periods in the field and successful controlled cross-pollinations. 3The F1 crop,wild hybrids result from pollination in the seed-production region by wild plants possessing the dominant bolting allele B for flowering without experiencing a period of cold. In the case of a transgene for herbicide tolerance incorporated into male-sterile seed-bearer plants, such hybrids will contain both the herbicide-tolerance and the bolting allele. Contamination of the fields by transgenic weed beets will be the result unless bolters are removed manually. The same will apply in the case of a cytoplasmically inherited transgene. 4Incorporation of the transgene into the pollinator plants will prevent the immediate formation of transgenic weed beets. However, in sugar beet fields, variety bolters may successfully cross-pollinate with weed beets in neighbouring fields. The use of diploid pollinator plants instead of tetraploids will considerably enhance gene flow towards wild beets, and is not, therefore, an attractive option. 5In conclusion, the appearance of transgenic weed beets is possible but can best be retarded if the transgene for herbicide tolerance is incorporated into the tetraploid pollinator breeding line. [source] Spatio-temporal pattern of Pentastiridius leporinus migration in an ephemeral cropping systemAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2010Alberto Bressan 1Cixiid planthoppers (Hemiptera: Fulgoromorpha: Cixiidae) are considered to be important economic pests because of their ability to transmit phloem-restricted prokaryotes causing emerging plant diseases worldwide. However, little information is available on the biology and ecology of such species. This is the case for Pentastiridius leporinus (Linnaeus), a cixiid planthopper reported to live on common reed across Countries of Central and Northern Europe. However, in the east of France, the same planthopper species appears to complete its life cycle in the sugar beet-wheat cropping system and has been repeatedly shown to transmit prokaryotic plant pathogens that are associated with an emerging disease of sugar beet called syndrome ,basses richesses'. 2To gather evidence on the biology of the planthopper in the cropping rotation, we analysed the flight activity of adults. We used transparent sticky traps for sampling migrating adults and quantified nymphs as well as emerging adults on the roots of wheat plants. 3Results showed a significant correlation between disappearance of nymphs and emerging adults from wheat roots and the occurrence of migrant adults in nearby sugar beet fields. Planthoppers migrated more abundantly and colonized sugar beet for longer periods than any other crop available. Flight activity was very pronounced during the migratory phase that was extended from the middle of June to the middle of July. A geographic information system and geostatical analysis revealed that planthoppers flew and colonized the centre of the sugar beet field rather than the borders. 4Overall, results obtained in the present study suggest that the ecology and biology of the planthopper vector in the cropping rotation is a primary factor that leads to the emergence of the syndrome ,basses richesses' disease of sugar beet. [source] Surveys for Beet Necrotic Yellow Vein Virus (the Cause of Rhizomania), other Viruses, and Soil-borne Fungi Infecting Sugar Beet in SyriaJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002A. M. Mouhanna Abstract Production of sugar beet, the most important source of sugar in Syria, has suffered from many problems in the past, especially from diseases. No previous surveys have been made in Syria for viral diseases and soil-borne fungi of sugar beet. In 1998, samples were collected from plants showing symptoms of virus infection (yellowing, wilting, necrosis and mosaic). Root samples (341) were collected from crops of autumn-sown seed from 115 localities in seven provinces, 173 root samples from spring-sown crops and 39 leaf samples were collected during both seasons. The root samples were tested for the presence of viruses by double antibody sandwich-enzyme-linked immunosorbent assay (ELISA) and triple antibody sandwich-ELISA, and for soil-borne fungi by red plate (Rose Bengal) dishes. We have shown for the first time the presence of Beet necrotic yellow vein virus, Beet soil-borne virus, Beet yellows virus and Beet mild yellowing virus in Syrian sugar beet fields in which Rhizoctonia sp. and Fusarium sp. were also widely distributed. [source] Tracing back seed and pollen flow within the crop,wild Beta vulgaris complex: genetic distinctiveness vs. hot spots of hybridization over a regional scaleMOLECULAR ECOLOGY, Issue 6 2004Frédérique Viard Abstract Hybrids between transgenic crops and wild relatives have been documented successfully in a wide range of cultivated species, having implications on conservation and biosafety management. Nonetheless, the magnitude and frequency of hybridization in the wild is still an open question, in particular when considering several populations at the landscape level. The Beta vulgaris complex provides an excellent biological model to tackle this issue. Weed beets contaminating sugar beet fields are expected to act as a relay between wild populations and crops and from crops-to-crops. In one major European sugar beet production area, nine wild populations and 12 weed populations were genetically characterized using cytoplasmic markers specific to the cultivated lines and nuclear microsatellite loci. A tremendous overall genetic differentiation between neighbouring wild and weed populations was depicted. However, genetic admixture analyses at the individual level revealed clear evidence for gene flow between wild and weed populations. In particular, one wild population displayed a high magnitude of nuclear genetic admixture, reinforced by direct seed flow as evidenced by cytoplasmic markers. Altogether, weed beets were shown to act as relay for gene flow between crops to wild populations and crops to crops by pollen and seeds at a landscape level. [source] Fate of the herbicides glyphosate, glufosinate-ammonium, phenmedipham, ethofumesate and metamitron in two Finnish arable soilsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 6 2006Pirkko Laitinen Abstract The fate of five herbicides (glyphosate, glufosinate-ammonium, phenmedipham, ethofumesate and metamitron) was studied in two Finnish sugar beet fields for 26 months. Soil types were sandy loam and clay. Two different herbicide-tolerant sugar beet cultivars and three different herbicide application schedules were used. Meteorological data were collected throughout the study and soil properties were thoroughly analysed. An extensive data set of herbicide residue concentrations in soil was collected. Five different soil depths were sampled. The study was carried out using common Finnish agricultural practices and represents typical sugar beet cultivation conditions in Finland. The overall observed order of persistence was ethofumesate > glyphosate > phenmedipham > metamitron > glufosinate-ammonium. Only ethofumesate and glyphosate persisted until the subsequent spring. Seasonal variation in herbicide dissipation was very high and dissipation ceased almost completely during winter. During the 2 year experiment no indication of potential groundwater pollution risk was obtained, but herbicides may cause surface water pollution. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||