Evaluation of Foliar-Applied Insecticides on Abundance of Parasitoids of Bemisia argentifolii (Homoptera: Aleyrodidae) in Vegetables2

2000 ◽  
Vol 35 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Alvin M. Simmons ◽  
D. Michael Jackson
Keyword(s):  
Relative Abundance ◽  
Kansas City ◽  
The Other ◽  
Bemisia Argentifolii ◽  
Vegetable Crops ◽  
Sticky Traps ◽  
Bayer Corporation ◽  
Field Plots

The relative abundance of parasitoids of Bemisia argentifolii Bellows & Perring was studied in insecticide-treated and untreated field plots of cantaloupe, collard, cucumber, and tomato. Treatments were made using foliar-applied chlorpyrifos (Lorsban®, DowElanco, Indianapolis, IN) in 1994, and foliar-applied imidacloprid (Provado®, Bayer Corporation, Kansas City, MO) in 1995 and 1996. Yellow sticky cards were used to monitor parasitoids associated with B. argentifolii in plots untreated or treated weekly in 1994 and bi-weekly in 1995 and 1996 with insecticide over 10 wks. The abundance of parasitoids varied among fields and across years. Five species of parasitoids were captured: Eretmocerus sp., Encarsia nigricephala Dozier, E. pergandiella Howard, E. quaintancei Howard, and E. strenua (Silvestri). The first three species comprised approximately 95% of the captured parasitoids. Parasitoids persisted in all field locations and crops whether the vegetables were treated or not. Parasitoids were captured in the treated plots throughout the study, although in fewer numbers than in the untreated plots. Overall, about 60 to 70% of parasitoids captured were from plots without insecticide. Whitefly captures on the sticky traps were relatively high in collard compared with the other crops studied. In addition, more E. nigricephala and E. pergandiella were collected in collard than in the other vegetable crops.

In vitro measurements of the competitive interactions between two saprobic basidiomycetes on Typha latifolia

2005 ◽  
Vol 83 (11) ◽  
pp. 1523-1527 ◽  
Author(s):  
Michael J. Schulz ◽  
James F. Cahill, ◽  
Randolph S. Currah
Keyword(s):  
Relative Abundance ◽  
Typha Latifolia ◽  
The Other ◽  
Competitive Interactions ◽  
In Vitro Measurements ◽  
Leaf Tissues ◽  
Leaf Segments

Psathyrella typhae (Kalchbr.) Pearson & Dennis forms small basidiomata (mushrooms) and Sclerotium hydrophilum Saccardo in Rothert numerous minute sclerotia at the base of senescent shoots of Typha latifolia L. To assess how the two might compete in nature, isolates of these fungi were paired on autoclaved leaf segments of T. latifolia and incubated at 15 and 25 °C. The relative abundance of each species in the segments was determined by macerating the leaf tissues and then transferring fragments of macerate to microplates containing two types of media: one conclusively demonstrated the presence of P. typhae while the other demonstrated the presence of S. hydrophilum. Relative numbers of microplate wells showing positive reactions for each species on each medium indicated the proportion of the segment occupied following single and paired inoculations. These data demonstrated that competition was asymmetric, with P. typhae the stronger competitor at both temperatures, and uninhibited by the presence of S. hydrophilum. In contrast, S. hydrophilum was competitively excluded by P. typhae.

scholarly journals Angolan vegetable crops have unique genotypes of potential value for future breeding programmes

2016 ◽  
Vol Volume 112 (Number 3/4) ◽  
Author(s):  
José P. Domingos ◽  
Ana M. Fita ◽  
María B. Picó ◽  
Alicia Sifres ◽  
Isabel H. Daniel ◽  
...  
Keyword(s):  
Strong Dependence ◽  
The Other ◽  
Vegetable Crops ◽  
Cucurbita Maxima ◽  
Capsicum Chinense ◽  
Local Markets ◽  
Potential Value ◽  
Wide Range ◽  
Different Types ◽  
Breeding Programmes

Abstract A survey was carried out in Angola with the aim of collecting vegetable crops. Collecting expeditions were conducted in Kwanza-Sul, Benguela, Huíla and Namibe Provinces and a total of 80 accessions belonging to 22 species was collected from farmers and local markets. Species belonging to the Solanaceae (37 accessions) and Cucurbitaceae (36 accessions) families were the most frequently found with pepper and eggplant being the predominant solanaceous crops collected. Peppers were sold in local markets as a mixture of different types, even different species: Capsicum chinense, C. baccatum, C. frutescens and C. pubescens. Most of the eggplant accessions collected belonged to Solanum aethiopicum L. Gilo Group, the so-called ‘scarlet eggplant’. Cucurbita genus was better represented than the other cucurbit crops. A high morphological variation was present in the Cucurbita maxima and C. moschata accessions. A set of 22 Cucurbita accessions from Angola, along with 32 Cucurbita controls from a wide range of origins, was cultivated in Valencia, Spain and characterised based on morphology and molecularity using a set of 15 microsatellite markers. A strong dependence on latitude was found in most of the accessions and as a result, many accessions did not set fruit. The molecular analysis showed high molecular variability and uniqueness in the collected accessions, as shown by their segregation from the set of global controls. In summary, the material collected is quite valuable because of its uniqueness and the potential of the breeding characteristics it possesses.

Response of some vegetable crops to soil-applied halides

1992 ◽  
Vol 72 (4) ◽  
pp. 555-567 ◽  
Author(s):  
S. C. Sheppard ◽  
W. G. Evenden
Keyword(s):  
Key Words ◽  
Soil Surface ◽  
Competitive Interaction ◽  
The Other ◽  
Vegetable Crops ◽  
Tissue Concentrations ◽  
Industrial Pollutants ◽  
High Concentrations ◽  
Corn Kernels ◽  
Key Words Fluoride

The halide elements are environmentally important and share some common attributes. The heaviest, I, and the lighest, F, are quite toxic and are important industrial pollutants. They are also effectively retained in soils. The others, Cl and Br, can be accumulated to high concentrations in plants, are used in agriculture and are highly mobile in soils. This study investigated the behaviour of the halides in plots, outdoor lysimeters, and laboratory sorption and excised-root experiments. Sorption on soil was ordered as F > I > Br > Cl. Concentrations in plants were generally ordered as CI ≥ Br > > F ≥ I, the inverse of the sorption ordering, as expected. Older tissues, which were also closest to the soil surface, had higher concentrations, and sequestered tissues, such as corn kernels and cabbage heads, had lower concentrations. There was evidence of competitive interaction among the halides and with soil anions such as phosphate and sulfate. This competition reduced the toxicity of I and modified tissue concentrations of the halides, P and S. Another interesting interaction was an increase in Cl and I sorption on soil solids when there were elevated levels or the other halides. Overall, the study of the halides in combination enhanced our understanding of their individual behaviours. Key words: Fluoride, chloride, bromide, iodide, vegetable

scholarly journals Population Dynamics of Released Potato Psyllids and their Bacteriliferous Status in Relation to Zebra Chip Incidence in Caged Field Plots

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1762-1767 ◽  
Author(s):  
F. Workneh ◽  
L. Paetzold ◽  
A. Rashed ◽  
C. M. Rush
Keyword(s):  
Disease Incidence ◽  
Sticky Trap ◽  
Research Station ◽  
Zebra Chip ◽  
Sticky Traps ◽  
Monitoring Tools ◽  
Candidatus Liberibacter ◽  
Yellow Sticky Trap ◽  
Successive Generations ◽  
Field Plots

Potato psyllids vector ‘Candidatus Liberibacter solanacearum’ (Lso), the putative causal agent of potato zebra chip (ZC). Currently, sticky traps are the primary psyllid monitoring tools used by growers for making management decisions. However, the reliability of sticky traps in predicting psyllid numbers in potato fields has always been questioned. In 2013 and 2014, experiments were conducted in covered field plots at the Texas A&M AgriLife Research Station at Bushland to investigate the relationships among initial psyllid numbers, psyllids captured on sticky traps and their Lso status, and zebra chip incidence. Three densities of Lso-positive psyllids (5, 15, or 30/cage) were released under 2-week-old potato canopies with four replications in plot sizes of 7.6 to 9 m by 5 rows. Psyllids were released under the first plant in the center row and monitored weekly with a yellow sticky trap from the opposite end. Number of plants with zebra chip symptoms also was counted weekly beginning one month after infestation with psyllids. The total number of psyllids captured on sticky traps and disease incidence levels generally corresponded to the levels of psyllid density treatments (5 < 15 < 30), but the differences became more apparent toward the end of the experiments. Psyllid numbers in the different density treatments fluctuated more or less in synchrony over time, which appeared to reflect periodic emergence of new generations of psyllids. Initially, all captured psyllids tested positive for Lso. However, the proportions of psyllids testing positive declined dramatically after a few weeks, which suggested that the new generations of psyllids were devoid of Lso. Over all, less than 50% of captured psyllids tested positive for the pathogen. The decline in proportions of psyllids testing positive for Lso following successive generations has significant relevance to field situations and may partly explain why there are generally low percentages of Lso-positive psyllids under field conditions.

scholarly journals Cretaceous amniote integuments recorded through a taphonomic process unique to resins

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sergio Álvarez-Parra ◽  
Xavier Delclòs ◽  
Mónica M. Solórzano-Kraemer ◽  
Luis Alcalá ◽  
Enrique Peñalver
Keyword(s):  
The Other ◽  
Characteristic Scale ◽  
Sticky Traps ◽  
Fossil Records ◽  
Mammalian Hair

AbstractFossil records of vertebrate integuments are relatively common in both rocks, as compressions, and amber, as inclusions. The integument remains, mainly the Mesozoic ones, are of great interest due to the panoply of palaeobiological information they can provide. We describe two Spanish Cretaceous amber pieces that are of taphonomic importance, one bearing avian dinosaur feather remains and the other, mammalian hair. The preserved feather remains originated from an avian dinosaur resting in contact with a stalactite-shaped resin emission for the time it took for the fresh resin to harden. The second piece shows three hair strands recorded on a surface of desiccation, with the characteristic scale pattern exceptionally well preserved and the strands aligned together, which can be considered the record of a tuft. These assemblages were recorded through a rare biostratinomic process we call “pull off vestiture” that is different from the typical resin entrapment and embedding of organisms and biological remains, and unique to resins. The peculiarity of this process is supported by actualistic observations using sticky traps in Madagascar. Lastly, we reinterpret some exceptional records from the literature in the light of that process, thus bringing new insight to the taphonomic and palaeoecological understanding of the circumstances of their origins.

Mass Spectra of Some Carbamates and Related Ureas. II

1968 ◽  
Vol 51 (2) ◽  
pp. 347-365 ◽  
Author(s):  
W R Benson ◽  
J N Damico
Keyword(s):  
Spectral Data ◽  
Relative Abundance ◽  
Mass Spectra ◽  
The Other ◽  
Methyl Isocyanate ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Sulfur Containing

Abstract Mass spectral data for fourteen carbamates, live dithiocarbamates, one thiocarbamate, and eight phenylureas are given with some interpretations. Among the compounds examined were some sulfur-containing aliphatic oxime carbamates; these lost the sulfur moieties more easily than the methyl isocyanate moiety. In the aryl IV-methylcarbamate series, the CH3NCO moiety appears to be lost most easily, as it is in pyrolysis. When l-(2-chlorophenyI)-3- methylurea is fragmented, unexpectedly the [HNC0]+ ion is found in high relative abundance. However, the remaining ureas undergo fragmentation in a manner similar to their related carbamates. Although the two ethylene bisdithiocarbamates give essentially identical fragmentation patterns, the spectra of the other four thio- and dithiocarbamates show sufficient differences so that they may be distinguished from one another.

Yield improvement in high lysine barley

1981 ◽  
Vol 32 (3) ◽  
pp. 425 ◽  
Author(s):  
RN Oram ◽  
H Doll
Keyword(s):  
Crude Protein ◽  
Seed Protein ◽  
Unit Area ◽  
Energy Content ◽  
The Other ◽  
Seed Composition ◽  
High Lysine ◽  
Seed Yield Components ◽  
Field Plots ◽  
Barley Genotypes

Twenty-three barley genotypes were grown in field plots and the seed-yield components and seed composition were investigated. Ten malting and feed cultivars and waxy endosperm selection lines had the standard concentration of lysine in their seed protein. The other genotypes were five different natural or induced high-lysine mutants and/or selection lines developed from them. High-lysine lines were lower yielding than the most productive normal lysine cultivars because of a decrease in weight per seed, accompanied by a reduced content of the carbohydrates extractable with dimethyl sulfoxide. Ris� mutant no. 7 was exceptional in having fewer seeds per unit area and a normal carbohydrate content. Within the group of lys 3 homozygotes derived from Ris� no. 1508, the higher yielding lines had more seeds per unit area, higher concentrations of extractable carbohydrates, and lower concentrations of crude protein. Similar trends with yield also occurred among the lines homozygous for the lys gene from Hiproly. The yields of the most productive lys and lys 3 homozygotes approached that of Clipper, the leading Australian malting cultivar, but were 25% lower than that of the most productive feed barley, Cutter. The other mutants, Ris� no. 7, Ris� no. 29 and Clipper 500, were lower yielding than the better lys and lys 3 selections. The possibilities for improving the yield and energy content of the latter two high-lysine types by selection are discussed.

Five decades of research on phytoplasma-induced witches' broom diseases.

2021 ◽  
Vol 16 (002) ◽  
Author(s):  
Chamran Hemmati
Keyword(s):  
Plant Species ◽  
Ornamental Plants ◽  
Fruit Trees ◽  
The Other ◽  
Economic Losses ◽  
Common Disease ◽  
Vegetable Crops ◽  
Management Options ◽  
Disease Symptoms ◽  
Broom Disease

Abstract Phytoplasmas, prokaryotic wall-less microorganisms, are important pathogens of several plant species in most parts of the world. Phytoplasmas have been reported associated with various symptoms on hundreds of plant species. Witches' broom disease (WBD) is one of the most common disease symptoms, which is caused by phytoplasma strains belonging to different phytoplasma groups. Symptoms of the disease differ from one host to the other as well as from one phytoplasma strain to the other. However, WBD symptoms are usually characterized by the production of a large number of small leaves, accompanied in some host plants by the production of several branches/shoots. Phytoplasma strains belonging to more than 13 groups and 39 subgroups have been reported associated with WBD in more than 116 plant species. Most of the phytoplasma strains causing WBD symptoms in plant species belong to the 16SrII and 16SrI groups, mainly 16SrII-D and 16SrI-B subgroups. The current review provides information on the different types of phytoplasma strains associated with WBD symptoms in ornamental plants, medicinal plants, forest trees, weeds, vegetable crops, field crops, and fruit trees. Emphasis is on WBD on acid limes, almonds, peanuts, jujube, and cassava that have resulted in significant economic losses in different countries. Description of the symptoms, phytoplasma groups, and management options is also provided for some of the diseases.

Widowhood in Elderly Women: Exploring its Relationship to Community Integration, Hassles, Stress, Social Support, and Social Support Seeking

1992 ◽  
Vol 35 (4) ◽  
pp. 253-264 ◽  
Author(s):  
Julie Pellman
Keyword(s):  
Social Support ◽  
Kansas City ◽  
Elderly Women ◽  
Community Integration ◽  
Daily Hassles ◽  
The Other ◽  
Social Support Seeking ◽  
Seeking Behavior ◽  
Experience Of Stress ◽  
Support Seeking

This study examined the degree to which widows were integrated in their community, the daily hassles and stress they may have experienced, and their social networks and support-seeking behavior. A sample of 160 women, sixty years of age or older, eighty widows and eighty non-widows were interviewed. Half the sample participated in senior centers in Kansas City, Missouri, while the other half belonged to other organizations or were obtained through a truncated snowball technique. The findings indicated that widowhood in and of itself does not appear to be a predictor either of community integration or the lack of it or the experience of stress and hassles. Those who experienced hassles were not the same persons as those who experienced stress. It was surprising to find that those who sought social support did not seem most in need of it. Age and education, along with community integration, were better predictors of the variables studied than was widowhood.

Étude des relations entre les communautés piscicoles et les différents habitats d'une rivière nordique: notion d'habitat optimal

1982 ◽  
Vol 60 (12) ◽  
pp. 3344-3352
Author(s):  
Louise Savard ◽  
Guy Moreau
Keyword(s):  
Relative Abundance ◽  
Condition Factor ◽  
Northern Pike ◽  
Abundant Species ◽  
The Other ◽  
Coregonus Clupeaformis ◽  
Habitat Types ◽  
Linkage Cluster ◽  
Complete Linkage Cluster ◽  
Satellite Species

A complete linkage cluster analysis using the physical characteristics of the sampling sites has revealed the existence of five groups corresponding to five habitat types nonequally distributed in a northern Quebec river. According to the results of discriminant analysis using the relative abundance of the fish species present, these habitats support populations which differ by the relative abundance of species and not by the presence or absence of some particular species. A habitat is first characterized by a species living preferentially in this habitat, then by the other species inhabiting the area in an opportunistic way, and finally by some satellite species which do not seem to have any marked requirements. A habitat is considered as optimal for a species first if this species inhabits this area preferentially to others and secondly if this use is more advantageous for growth or condition factor. This seems to be confirmed for two of the most abundant species, northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis), both of which have a higher condition factor and a better growth in the part of the river where their optimal habitat is more frequently found.

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