scholarly journals Spissistilus festinus (Hemiptera: Membracidae) susceptibility to six generalist predators

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242775
Author(s):  
Cindy R. Kron ◽  
Mark S. Sisterson
Keyword(s):  
Petri Dish ◽  
Field Testing ◽  
Biocontrol Agents ◽  
Bean Plant ◽  
Sugar Accumulation ◽  
Generalist Predators ◽  
Wine Quality ◽  
Greenhouse Study ◽  
Spissistilus Festinus ◽  
Significant Mortality

Spissistilus festinus (Say) (Hemiptera: Membracidae) was shown to transmit Grapevine red blotch virus (GRBV) in a greenhouse study. Grapevines infected with GRBV exhibit reduced sugar accumulation, altered secondary metabolite production and delayed berry maturation that negatively impacts wine quality and economics. Augmentative biocontrol may be a useful integrated pest management (IPM) tool for suppressing S. festinus populations in vineyards, but minimal research has been conducted on testing potential predators against the different life stages of S. festinus. The susceptibility of S. festinus adults and nymphs (1st through 5th instar) to predation by six commercially available biocontrol agents in petri dish and bell bean plant arenas was determined under greenhouse conditions. No significant mortality of S. festinus nymphs or adults occurred when exposed to Cryptolaemus montrouzieri adults, C. montrouzieri larvae and Sympherobius barberi adults in petri dish or bell bean plant arenas. Significant mortality of 1st and 2nd instar nymphs of S. festinus in the presence of Zelus renardii nymphs was observed in petri dish but not in bell bean arenas. Hippodamia convergens adults and Chrysoperla rufilabris larvae both consumed a significant number of S. festinus nymphs in petri dish and bell bean arenas. No significant predation of S. festinus adults was documented in this experiment. Results of this study aid in identifying predators that may be suitable candidates for additional field testing to determine their potential efficacy as biocontrol agents of S. festinus in a vineyard setting.

Timing the Implementation of Cultural Practices for Spissistilus festinus (Hemiptera: Membracidae) in California Vineyards Using a Stage-Structured Degree-Day Model

2020 ◽  
Vol 113 (5) ◽  
pp. 2558-2562
Author(s):  
Emily N Bick ◽  
Cindy R Kron ◽  
Frank G Zalom
Keyword(s):  
Emerging Adults ◽  
Cover Crops ◽  
Cultural Practices ◽  
Cultural Control ◽  
Control Measures ◽  
Late Winter ◽  
Wine Quality ◽  
Degree Day ◽  
Greenhouse Study ◽  
Spissistilus Festinus

Abstract The three-cornered alfalfa hopper, Spissistilus festinus (Say), was shown to transmit Grapevine red blotch virus (GRBV), the causative agent for Grapevine red blotch disease, in a greenhouse study on grapes. GRBV is a major concern of wine grape growers due to its economic impact on wine quality. Plants in the family Fabaceae are preferred hosts of S. festinus and are commonly planted as cover crops or present in a vineyard’s native vegetation. In late winter, during grapevine dormancy, S. festinus migrate into vineyards to feed and reproduce on these cover crop and weed hosts. Tilling vineyard floor vegetation provides growers an opportunity to disrupt the life cycle of early instars that are relatively immobile, reducing the S. festinus first-generation population. Nymphal presence is difficult to detect. First through third instars were not detected in sweep net samples in a 2-yr weekly sampling study, whereas fourth and fifth instars were first found on the same sample date as emerging adults. A degree-day model was developed and successfully predicted when early S. festinus instars are present in the vineyard to aid in exploiting the time period when S. festinus is most susceptible to cultural control measures.

TOXICITY OF INSECTICIDES TO THE ALFALFA LEAFCUTTER BEE, MEGACHILE ROTUNDATA F. (HYMENOPTERA: MEGACHILIDAE), ESTABLISHED BY THREE EVALUATION METHODS

1988 ◽  
Vol 120 (4) ◽  
pp. 297-305 ◽  
Author(s):  
W. A. Charnetski
Keyword(s):  
Petri Dish ◽  
Evaluation Methods ◽  
Laboratory Evaluation ◽  
Evaluation Procedure ◽  
Megachile Rotundata ◽  
Field Cage ◽  
Male And Female ◽  
Significant Difference ◽  
Leafcutter Bee ◽  
Significant Mortality

AbstractThree methods—tube chambers (ventilated and unventilated), petri dish chambers, and field cages—were used to evaluate the toxicity of deltamethrin, trichlorfon, and methoxychlor deposits on alfalfa, Medicago sativa L., to 1- to 7-day-old alfalfa leafcutter bees, Megachile rotundata (F.), 24 and 48 h after exposure. In unventilated tube chambers, all three insecticides were significantly toxic to male bees after 24 and 48 h, but only deltamethrin and trichlorfon were significantly toxic to female bees after 24 h. In ventilated tube chambers, only deltamethrin was significantly toxic by contact and then only to male bees at 24 h. Significant vapor action was observed only for trichlorfon and only in unventilated tube chambers. By the petri dish method, only deltamethrin caused significant mortality to male and female bees. However, bee mortality increased significantly between 24 and 48 h. By the field cage method, there was no significant difference in mortality among treatments and controls within the 24- and 48-h evaluations. Bee mortality in the controls was much higher in the petri dish and field cage methods than in either of the two variations of the tube chamber method. The three evaluation methods are compared and the need for a standardized laboratory evaluation procedure is discussed.

scholarly journals Terroir - Myth and/or Reality - Outstanding Marketing Idea? A Review

2017 ◽  
Vol 45 (2) ◽  
pp. 332-342
Author(s):  
Klaus SCHALLER
Keyword(s):  
Production Systems ◽  
Heat Budget ◽  
Quality Parameters ◽  
Sugar Accumulation ◽  
Soil Parameters ◽  
Wine Quality ◽  
Production Chain ◽  
Juice Extraction ◽  
Marketing Activities ◽  
Human Skills

In former times the term terroir was connatated negatively. “Le goût du terroir” concerned wines, which could not be sold outside a region, because of quality defects. Later, “terroir products” included agricultural goods produced in specific areas. French scientists developed during the last 3 decennials a scientific base for the system “terroir”. All agricultural production systems adhere to a “unité terroir de base (UTB)”. An interaction with viticulture, changes it to a “unité terroir viticole (UTV)”. An UTV together with a farm or an AOC creates an identifiable typicity of wines. Other groups of scientists in esp. in Germany tried to find out the influences of meso- and microclima on quality parameters of grapevines as well as soil, nutrients, water and soil heat budget. Mesoclimatic, geomorphological, and soil parameters can explain approximately 60-70% of the yield formation as well as the sugar accumulation in berries.  The unexplained variability adheres to human skills, soil management, harvesting techniques etc.. Following the production chain from bunches to wine increasing interventions occur: juice extraction systems, spontaneous or controlled fermentation with defined yeast strains. Temperature control, filtration systems will exert an influence on the final wine quality. In contrast to the limited intervention during production of grapes, wine making exceed by far the first mentioned and terroir turns to a “quantité negligeable” in the final wine. Nonetheless, on the consumers’ side terroir is still in discussion. Producers have to respect these movements and have to develop strategies how to incorporate those ideas in their production schemes and their marketing activities.

Can Generalist Predators be Effective Biocontrol Agents?

2002 ◽  
Vol 47 (1) ◽  
pp. 561-594 ◽  
Author(s):  
W. O. C. Symondson ◽  
K. D. Sunderland ◽  
M. H. Greenstone
Keyword(s):  
Biocontrol Agents ◽  
Generalist Predators

scholarly journals Seasonal differences in Vitis vinifera L. cv. Pinot noir fruit and wine quality in relation to climate

OENO One ◽  
2019 ◽  
Vol 53 (2) ◽  
Author(s):  
Magali Blank ◽  
Marco Hofmann ◽  
Manfred Stoll
Keyword(s):  
Climate Change ◽  
Vitis Vinifera ◽  
Weather Conditions ◽  
Pinot Noir ◽  
Sugar Accumulation ◽  
Vitis Vinifera L ◽  
Maturity Stage ◽  
Wine Quality ◽  
Micro Scale ◽  
The Impact

Aims: A better understanding of the relationship between weather conditions and wine quality would provide tools for assessing the impact of climate change and the potential for adaptation. Most studies rely on assessing wine quality by the price per bottle or by an overall ranking and then establishing general relations to weather conditions. However, such an approach may imply the addition of bias by variable winemaking techniques overcoming vintage effects. The aim of our study was therefore to implement a controlled conditions approach using grape samples from a single vineyard and a standardized micro-scale winemaking technique to produce wines in similar conditions for each vintage over more than a decade. We hope that this data will allow new insights into responses to climatic differences.Methods and results: From 2005 to 2015, data was collected from a vineyard of Hochschule Geisenheim University planted with Vitis vinifera L. cv. Pinot Noir grafted on rootstock SO4 in four field replicates. Weather conditions were recorded together with the major phenological stages, yield, infection of the bunches by Botrytis cinerea bunch rot, and pruning weight. Key primary juice compounds were analyzed and berry phenolics in skins and seeds were determined before harvest. Micro-scale winemaking was developed to produce wines in standardized conditions. The repeatability of the method to assess the extraction of anthocyanins and tannins was shown to be 2–10% and 8–12%, respectively, depending on grape maturity stage. Sugar accumulation was coupled to warmer conditions during the maturation period, and high temperatures after véraison decreased the concentration of malic acid in the juice. The accumulation of primary amino acids (N-OPA) in the juices seemed positively related to warmer conditions between bud break and flowering. Increased temperature, especially before véraison, accompanied by a lack of precipitation was related to an accumulation of tannins in fruit and wine, with a higher accumulation in skins than seeds. The temperature-sensitive anthocyanin accumulation in grapes was coupled to warmer conditions after véraison. These differences in anthocyanin concentration could also be observed in the wine.Conclusions: High-quality vintages were linked to warmer than normal growing seasons and below normal precipitation.Significance and impact of the study: The use of a micro-scale winemaking technique represents an innovative tool to provide detailed information in a controlled and reproducible way. A better understanding of the interaction between weather conditions and berry/wine compounds will help with developing improved winemaking techniques and better adapting to future impacts of climate change.

scholarly journals A whole canopy gas exchange system for the targeted manipulation of grapevine source-sink relations using sub-ambient CO2

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Jason P. Smith ◽  
Everard J. Edwards ◽  
Amanda R. Walker ◽  
Julia C. Gouot ◽  
Celia Barril ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Area ◽  
Canopy Structure ◽  
Experimental System ◽  
Soda Lime ◽  
Sugar Accumulation ◽  
Wine Quality ◽  
Gas Exchange System ◽  
Berry Composition ◽  
Source Sink

Abstract Background Elucidating the effect of source-sink relations on berry composition is of interest for wine grape production as it represents a mechanistic link between yield, photosynthetic capacity and wine quality. However, the specific effects of carbohydrate supply on berry composition are difficult to study in isolation as leaf area or crop adjustments can also change fruit exposure, or lead to compensatory growth or photosynthetic responses. A new experimental system was therefore devised to slow berry sugar accumulation without changing canopy structure or yield. This consisted of six transparent 1.2 m3 chambers to enclose large pot-grown grapevines, and large soda-lime filled scrubbers that reduced carbon dioxide (CO2) concentration of day-time supply air by approximately 200 ppm below ambient. Results In the first full scale test of the system, the chambers were installed on mature Shiraz grapevines for 14 days from the onset of berry sugar accumulation. Three chambers were run at sub-ambient CO2 for 10 days before returning to ambient. Canopy gas exchange, and juice hexose concentrations were determined. Net CO2 exchange was reduced from 65.2 to 30 g vine− 1 day− 1, or 54%, by the sub-ambient treatment. At the end of the 10 day period, total sugar concentration was reduced from 95 to 77 g L− 1 from an average starting value of 23 g L− 1, representing a 25% reduction. Scaling to a per vine basis, it was estimated that 223 g of berry sugars accumulated under ambient supply compared to 166 g under sub-ambient, an amount equivalent to 50 and 72% of total C assimilated. Conclusions Through supply of sub-ambient CO2 using whole canopy gas exchange chambers system, an effective method was developed for reducing photosynthesis and slowing the rate of berry sugar accumulation without modifying yield or leaf area. While in this case developed for further investigations of grape and wine composition, the system has broader applications for the manipulation and of study of grapevine source-sink relations.

scholarly journals Must characteristics of selected grapevine varieties used for local wine production

2010 ◽  
Vol 46 (Special Issue) ◽  
pp. S82-S84
Author(s):  
P. Vrána ◽  
O.M. Jandurová
Keyword(s):  
Environmental Conditions ◽  
Pinot Noir ◽  
Sugar Accumulation ◽  
Wine Quality ◽  
Wine Production ◽  
Wine Making

The must characteristics of some old varieties (present on the list of varieties allowed for land wine making) were compared with their commercial relatives, in order to estimate their specific benefits and advantages for wine processing. In the case of Portuguese blue and Pinot noir pr飯ce, we additionally identified the influences of environmental conditions on their must composition and wine quality. Clear differences in sugar accumulation among varieties were detected, as well as differences in earliness.

scholarly journals The Salinity Effects on Germination and Early Seedling Growth of Bean Plants (Bean Phaseolus)

2020 ◽  
Keyword(s):  
Seedling Growth ◽  
Germination Rate ◽  
Petri Dish ◽  
Normal Weight ◽  
Bean Plant ◽  
Control Group ◽  
Early Seedling Growth ◽  
Bean Plants ◽  
Root And Shoot Length ◽  
Early Seedling

The study was conducted at Dilla University, in the laboratory of Biological sciences to see the effects of salinity on germination and early seedling. Objectives:Background: It is estimated that the world 20% of farming land and 50% of cropland is salt stressed and salinity decreases the germination of seed, retards the growth of plant and so it reduces the yield of crop. Objectives: The major objective of this research was to evaluate the effects of salinity on the germination and early seedling growth of bean plants. Specifically, to investigate salt tolerant efficiency, salt effect on seed germination and its rate and growth of bean plant at different concentration of NaCl. Methodology: The experiment required 21 groups, of which 20 of them were experimental with different salt concentrations ranging from 0.05M to 1.00M with 0.05M difference and one control group. Each group contain three bean seed measuring its weight using electronic balance machine, sterilized with 70% Alcohol solution for 15 seconds, rinsed with distilled water, placed in separate Petri dish using a forceps, 50ml of solution were added to each Petri dish with different concentration, all Petri dishes were covered with lids and kept into incubator at room temperature for 17 days, germinated seed were counted, seedlings root and shoot length were measured using a ruler. Finally, the Bean was transferred to non-saline condition, weight of germinated Bean were measured to compare with their normal weight and to determine the effects of salt on seed weight, which was conducted in triplicates. All necessary data was taken, analyzed and interpreted in the form of percentage, graph, tables and figures. Result: When the concentration of salt increased the Bean plant is extremely affected, germination rate decreased and the terminal weights of seed were become lower than the initial weight due to the absorption of water by seed. Conclusions: The rate of germination decrease when the salt concentration increased and late growth of length of root and shoot when the salt dosage is highest and also the weights of seed reduced as concentration of salt is raised. Generally, as the concentration of salt is increased the Bean plant is extremely affected.

scholarly journals Exotic predators are not better biocontrol agents: the harlequin ladybird is not the most voracious in Mexico

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12503
Author(s):  
Morelia Camacho-Cervantes ◽  
Wendy Mendoza-Arroyo ◽  
Daniela Arellano-Sánchez ◽  
Ek del-Val
Keyword(s):  
Native Species ◽  
Harmonia Axyridis ◽  
Biocontrol Agents ◽  
Foraging Efficiency ◽  
Generalist Predators ◽  
Harlequin Ladybird ◽  
Ecological Requirements ◽  
Exotic Invasive ◽  
Aphid Biocontrol ◽  
Eggs And Larvae

The use of exotic species for pest biocontrol has been a common pathway for introduction and dispersal of invasive species that may have undesired outcomes. Biocontrol agents are believed to be a less damaging alternative than pesticides, but some species may also prey on or parasitize native species or outcompete them for resources. The harlequin ladybird (Harmonia axyridis) is a well-known biocontrol agent originally from Asia that has established invasive populations in 59 countries around the globe. Harlequin ladybirds are generalist predators that in addition to pests prey on an array of different species including other coccinelids’ eggs and larvae. In Mexico, native ladybirds that share ecological requirements with harlequin ladybirds are at risk of being outcompeted and predated upon. The aim of our study was to compare the foraging efficiency of harlequin ladybirds against three species of native coccinelids when preying on aphids. We investigated the foraging behaviour of ladybirds alone and in pairs with a conspecific, a native heterospecific or an exotic heterospecific. We found that the native Cycloneda sanguinea was the species that consumed the most aphids, while Hippodamia convergens was the fastest to find and consume each aphid. Harlequin ladybirds and H. convergens consumed the same number of aphids while P. vittigera consumed less. Conspecific competition was stronger than heterospecific competition. We discuss the suitability of using the exotic invasive harlequin ladybird for aphid biocontrol in comparison with native coccinelids.

scholarly journals The potential of entomopathogenic nematodes as biocontrol agents for clover root weevil (Sitona lepidus)

2000 ◽  
Vol 53 ◽  
pp. 48-53 ◽  
Author(s):  
N.L Bell ◽  
T.A. Jackson ◽  
T.L. Nelson
Keyword(s):  
Adult Development ◽  
Entomopathogenic Nematodes ◽  
Petri Dish ◽  
Biocontrol Agents ◽  
Controlled Environment ◽  
Pot Experiments ◽  
Sitona Lepidus ◽  
Survival And Development ◽  
Clover Root ◽  
Potential Use

The efficacy of the entomopathogenic nematodes Heterorhabditis zealandica H bacteriophora Steinernema carpocapsae and S feltiae against clover root weevil (CRW) larvae and pupae was determined in petri dish and pot experiments Field collected third instar (L3)pupal CRW immature stages were used and experiments were conducted in a controlled environment room at 18C Weevil survival and development was assessed 7 and 10 days after nematode inoculation for petri and pot experiments respectively All nematodes significantly reduced CRW survival and all except S feltiae prevented adult development Under the conditions used in this study Heterorhabditis spp were generally more effective than Steinernema spp Results are discussed in terms of the potential use of entomopathogenic nematodes as biocontrol agents for this clover pest

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