scholarly journals Photoperiod Effect on Megachile rotundata (Hymenoptera: Megachilidae) Female Regarding Diapause Status of Progeny: The Importance of Data Scrutiny

2020 ◽  
Vol 49 (2) ◽  
pp. 516-527
Author(s):  
Theresa L Pitts-Singer
Keyword(s):  
Regulatory Mechanism ◽  
Adult Emergence ◽  
Field Studies ◽  
Outcome Data ◽  
Western North America ◽  
Megachile Rotundata ◽  
Medicago Sativa L ◽  
Maternal Exposures ◽  
And Control ◽  
Long Photoperiod

Abstract Megachile rotundata F. populations are managed to pollinate alfalfa, Medicago sativa L. (Fabaceae), for seed production in western North America. Some progeny produced in summer by overwintered M. rotundata females enter diapause as prepupae to overwinter and become adults the following year. Other offspring avert diapause to undergo adult emergence in summer. The regulatory mechanism(s) of diapause induction or aversion is unknown; the process apparently involves multiple and integrated factors. This 4-yr study sought to determine effects of the exposure of mother bees to short, long, very long, and natural photoperiods on their production of non-diapausing and diapausing progeny. Just-emerged adult bees from both Utah and Canada sources were exposed to different photoperiods for 3 d in incubators and then released into field enclosures placed over blooming alfalfa. Control bees were those exposed to only outdoor conditions. Reproduction was monitored for each female bee, and offspring diapause outcome was recorded. Progeny outcome data were informative for only two of the four study years. Generally, progeny of Utah mothers exposed to long and very long photoperiods were more likely to be non-diapausers compared to progeny of mothers exposed to short and control photoperiods. Short and long (but not very long) photoperiod maternal exposures increased the likelihood of diapause aversion in Canada progeny. Performing multiyear field studies on geographically distinct populations is imperative for revealing environmental challenges and inconsistent bee performance that can impair analyses and interpretation. Future similar studies are needed to more fully evaluate photoperiod effects on diapause.

Nectar sugar production in alfalfa fields treated with several herbicides

1995 ◽  
Vol 75 (2) ◽  
pp. 521-524
Author(s):  
P. S. Curry ◽  
J. Waddington ◽  
N. Malik ◽  
G. G. Bowes
Keyword(s):  
Field Studies ◽  
Early Spring ◽  
Sugar Production ◽  
Winter Dormancy ◽  
Megachile Rotundata ◽  
Cocoon Production ◽  
Leafcutter Bee ◽  
Nectar Sugar ◽  
Medicago Sativa L ◽  
Herbicide Effects

Field studies were conducted at three sites in northeastern Saskatchewan to determine the effects of several herbicides applied in late fall or early spring on nectar sugar production in alfalfa (Medicago sativa L.) grown for seed. In general, sugar production was not affected detrimentally by the herbicides, but at one site alfalfa treated annually with metribuzin for 4 yr at the break of winter dormancy produced flowers in early July containing significantly less nectar sugar than flowers of plants not treated with herbicide. Increases in nectar sugar production sometimes occurred. At one site, chlorsulfuron at 0.11 kg ha−1 or more, hexazinone at 1.0 kg ha−1 and dichlobenil at 2.4 kg ha−1 increased nectar sugar production in early August. Herbicide effects were not consistent among sites, and it seems unlikely that leafcutter bee (Megachile rotundata Fabr.) cocoon production will be affected significantly by these weed control practices. Key words: Metribuzin, hexazinone, chlorsulfuron, terbacil, dichlobenil, imazethapyr

Evaluation of weed control in acetyl coA carboxylase-resistant rice with mixtures of quizalofop and auxinic herbicides

2019 ◽  
Vol 34 (4) ◽  
pp. 498-505
Author(s):  
Tameka L. Sanders ◽  
Jason A. Bond ◽  
Benjamin H. Lawrence ◽  
Bobby R. Golden ◽  
Thomas W. Allen ◽  
...  
Keyword(s):  
Weed Control ◽  
Rice Yield ◽  
Field Studies ◽  
Growth Stages ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Herbicide Treatments ◽  
Herbicide Mixture ◽  
Sequential Treatments ◽  
And Control

AbstractRice with enhanced tolerance to herbicides that inhibit acetyl coA carboxylase (ACCase) allows POST application of quizalofop, an ACCase-inhibiting herbicide. Two concurrent field studies were conducted in 2017 and 2018 near Stoneville, MS, to evaluate control of grass (Grass Study) and broadleaf (Broadleaf Study) weeds with sequential applications of quizalofop alone and in mixtures with auxinic herbicides applied in the first or second application. Sequential treatments of quizalofop were applied at 119 g ai ha−1 alone and in mixtures with labeled rates of auxinic herbicides to rice at the two- to three-leaf (EPOST) or four-leaf to one-tiller (LPOST) growth stages. In the Grass Study, no differences in rice injury or control of volunteer rice (‘CL151’ and ‘Rex’) were detected 14 and 28 d after last application (DA-LPOST). Barnyardgrass control at 14 and 28 DA-LPOST with quizalofop applied alone or with auxinic herbicides EPOST was ≥93% for all auxinic herbicide treatments except penoxsulam plus triclopyr. Barnyardgrass control was ≥96% with quizalofop applied alone and with auxinic herbicides LPOST. In the Broadleaf Study, quizalofop plus florpyrauxifen-benzyl controlled more Palmer amaranth 14 DA-LPOST than other mixtures with auxinic herbicides, and control with this treatment was greater EPOST compared with LPOST. Hemp sesbania control 14 DA-LPOST was ≤90% with quizalofop plus quinclorac LPOST, orthosulfamuron plus quinclorac LPOST, and triclopyr EPOST or LPOST. All mixtures except quinclorac and orthosulfamuron plus quinclorac LPOST controlled ivyleaf morningglory ≥91% 14 DA-LPOST. Florpyrauxifen-benzyl or triclopyr were required for volunteer soybean control >63% 14 DA-LPOST. To optimize barnyardgrass control and rice yield, penoxsulam plus triclopyr and orthosulfamuron plus quinclorac should not be mixed with quizalofop. Quizalofop mixtures with auxinic herbicides are safe and effective for controlling barnyardgrass, volunteer rice, and broadleaf weeds in ACCase-resistant rice, and the choice of herbicide mixture could be adjusted based on weed spectrum in the treated field.

Collaborative WHO xylitol field studies in Hungary II. General background and control of the dietary regimen

1985 ◽  
Vol 43 (6) ◽  
pp. 349-357 ◽  
Author(s):  
Jolán Bánóczy ◽  
Arje Scheinin ◽  
Róbert Pados ◽  
Gyöngyi Ember ◽  
Palma Kertész ◽  
...  
Keyword(s):  
Field Studies ◽  
Dietary Regimen ◽  
And Control

scholarly journals First Report of Colletotrichum truncatum on Alfalfa in Turkey

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 100-100 ◽  
Author(s):  
C. Eken ◽  
E. Demirci
Keyword(s):  
Morphological Characteristics ◽  
Conidial Suspension ◽  
Colletotrichum Truncatum ◽  
First Report ◽  
Clear Area ◽  
Granular Cytoplasm ◽  
Symptomatic Tissue ◽  
Medicago Sativa L ◽  
Stem Lesions ◽  
And Control

During the summer of 1997 and 1998, a pathogen identified as Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore was isolated from lesions on stems of alfalfa (Medicago sativa L.) plants in Erzurum, Turkey. Typical symptoms on stems of mature plants were large, sunken, irregularly shaped black lesions. Twenty-eight cultures of C. truncatum were isolated from stem lesions. Acervuli containing spores and dark setae were observed within lesions. Conidia were hyaline, one-celled, falcate to nearly straight with a prominent clear area in the center of highly granular cytoplasm, and measured 16.3 to 20.6 × 3.1 to 4.5 μm. These morphological characteristics were consistent with the description of C. truncatum (1). The pathogenicity of two isolates was determined on alfalfa cv. Bilensoy. Alfalfa seedlings (6-week-old) were inoculated with a conidial suspension of the fungus (1.4 × 107 conidia per ml), incubated in a moist chamber for 3 days, and subsequently transferred to growth chambers maintained at 25°C with a 12-h photoperiod. Ten plants were inoculated with each isolate. Symptoms first appeared on stems 12 days after inoculation. Sunken, irregularly shaped black lesions occasionally girdled stems of plants inoculated with C. truncatum. Symptoms did not appear on stems of control plants inoculated with sterile distilled water. C. truncatum was reisolated from symptomatic tissue. This is the first report of C. truncatum on alfalfa from Turkey. Reference: (1) B. C. Sutton. 1992. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, U.K.

Studies in Ovipositional Behaviour and Control of Sex in Aphytis Melinus Debach, a Parasite of California Red Scale, Aonidiella Aurantii (Mask.).

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
I Abdelrahman
Keyword(s):  
Sex Ratio ◽  
Host Density ◽  
Adult Emergence ◽  
The Body ◽  
Maturation Stage ◽  
Aphytis Melinus ◽  
Egg Maturation ◽  
Mean Size ◽  
Accepted Practice ◽  
And Control

The growing adult female red scale was the most preferred stage for A. melinus, followed by the second growing instar and lastly the male prepupa. The numbers of scale parasitized, the total of eggs laid, the number of eggs per scale, sex ratio and size of the parasites produced were all ranked in the same order. The mean size of parasites produced within the third instar decreased as the number of parasites per host increased. In the absence of the preferred host stages, female A. melinus laid readily in the unpreferred stages. In both A. melinus and A, chrysomphali it was noted that in multi- parasitism pupation, pupal development and adult emergence of all parasites in one host were synchronized. In A. melinus the sex and number of eggs laid per host are influenced by the host's size and quality. When A. melinus laid more than one egg in one host, it laid female eggs first and male eggs later; apparently the spermatheca goes through a period of fatigue, and is incapable of delivering sperm to the eggs descending the oviduct. Sex ratio decreases with increase in number of parasites per host and density of parasite population relative to hosts. The deposition of parasite eggs in a host by one female was observed during a short cycle of oviposition. A. melinus laid its eggs both 'above' and 'below' the body of the scale, whereas A. chrysomphali did so exclusively 'below'. In young mated A. melinus, eggs laid above the body of the scale were females and those below were males, but in old mated females all eggs, wherever laid, were male. Host development stops as soon as a parasite egg is laid. A. melinus avoids laying eggs in already parasitized hosts. The stages of red scale were ranked according to the percentage of mutilated individuals as: first moult (most mutilated), second instar, first instar, third instar, male prepupa and male pupa; second-moult females, egg-maturation stage and crawler-producing stage were unmutilated. A. melinus sometimes partitions her clutch of eggs into two hosts, particularly when host density is high. Partitioning in A. melinus may substitute for the generally accepted practice of super- parasitism, which would not be appropriate because the parasite is able to distinguish between parasitized and unparasitized hosts, is able to sense host density and to distribute her progeny on available hosts. Partitioning is advantageous for biological control. Behaviour of oviposition, mutilation and mutilation feeding in A. melinus are described in detail.

Studies on the biology and control of Lachnosterna consanguinea (Blanch.), a pest of sugarcane in Bihar (India)

1961 ◽  
Vol 52 (3) ◽  
pp. 577-587 ◽  
Author(s):  
A. N. Kalea ◽  
J. P. Kulshreshtha
Keyword(s):  
Adverse Effect ◽  
Adult Emergence ◽  
Field Trials ◽  
Bufo Melanostictus ◽  
Grass Roots ◽  
Large Numbers ◽  
Acridotheres Tristis ◽  
Flight Season ◽  
Dry Out ◽  
And Control

The larvae of the Melolonthid beetle, Lachnosterna. consanguinea (Blanch.), have been found to be very destructive to sugarcane in the Dalmianagar area in Bihar, India, since 1956 when they were first recorded there. The pest has since been found to occur in serious numbers in certain adjoining areas and also in Bihta in Patna district. Damage is done by the larvae by feeding on cane roots. Heavily infested cane clumps dry out completely and in severe infestations as much as 80 per cent, of the crop is lost. The infestation occurs only on light sandy soils; crops on clay soils are not affected. The February-planted crop suffers more seriously than that planted in October. The adults have not so far been observed doing any damage to sugarcane.The emergence of adults starts in the last week of April, but a rush of emergence occurs only after the first shower of rain. The adults are nocturnal in habit and feed on leaves of certain bushes and trees during the night. They hide themselves in loose moist soil in day-time. Mating takes place after dusk during the flight season, and eggs are laid in the soil at a depth of 5 to 10 cm. The incubation period varies from 8 to 10 days. The young larvae move to cane roots after some initial feeding on grass roots. They are fully grown in 8 to 10 weeks' time when they move deeper into the soil and pupate in earthen cells at a depth of 0·3 to 1·5 m. The pupal period varies from 12 to 16 days and the pest overwinters in the adult stage. There is only one brood a year.The adults are active at night and are attracted to artificial light and can be destroyed in large numbers with the help of light-traps. Collections from the foliage of trees and shrubs at night is an easier and better method of destruction. Trials with insecticides applied as sprays to the foliage of shrubs in cages to which adults were immediately introduced showed that a suspension containing 0·5 per cent. DDT was effective and was superior to one of BHC.Replicated field trials carried out for the control of the larvae with various insecticides showed that BHG applied to the soil in a dust at the rate of 22·4 Ib. toxicant per acre was the most effective. This treatment, when applied-at planting time (February) had an adverse effect on germination; this effect was not observed when the application was made at the end of May. In subsequent replicated experiments, when BHC in a dust was applied in two instalments at the rate of 10 Ib. per acre at the end of May at the time of the rush of adult emergence, and in July, respectively, much better results were obtained without any adverse effect on the crop. BHC and other insecticides applied to the soil in sprays at 10 Ib. per acre at the end of May were ineffective.Amongst varieties of cane grown at the Bank Farm, Dalmianagar, Co.935 and B.O.3 showed a greater tolerance of injury by the larvae than the others.A Scoliid, Scolia aureipennis Lep., was observed to parasitise the grubs during September. The rate of parasitisation was only about 5 per cent.A disease caused by a fungus, Metarrhizium. anisopliae, was also observed to occur in the adults. Affected beetles died within 4 to 6 days.The common Indian toad (Bufo melanostictus) and the gecko (Gecko gecko) were seen preying on the adults in the evening when these were active. A number of birds, particularly the Indian crow (Corvus splendens) and mynah (Acridotheres tristis), also feed on the larvae when these are exposed during tillage operations.

scholarly journals Efficacy of Silver Dihydrogen Citrate and Steam Vapor against a Human Norovirus Surrogate, Feline Calicivirus, in Suspension, on Glass, and on Carpet

2018 ◽  
Vol 84 (12) ◽  
Author(s):  
David Buckley ◽  
Muthu Dharmasena ◽  
Angela Fraser ◽  
Charles Pettigrew ◽  
Jeffery Anderson ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Field Studies ◽  
Feline Calicivirus ◽  
Human Norovirus ◽  
Disease Symptoms ◽  
Hard Surface ◽  
Color Changes ◽  
The Government ◽  
And Control ◽  
A Current

ABSTRACTCarpets and other soft surfaces have been associated with prolonged and reoccurring human norovirus (HuNoV) outbreaks. Environmental hygiene programs are important to prevent and control HuNoV outbreaks. Despite our knowledge of HuNoV transmission via soft surfaces, no commercially available disinfectants have been evaluated on carpets. Our aim was to adapt a current standardized method for virucidal testing by assessing two disinfection technologies, silver dihydrogen citrate (SDC) and steam vapor, against one HuNoV surrogate, feline calicivirus (FCV), on wool and nylon carpets. First, we evaluated the effect of both technologies on the appearance of carpet. Next, we evaluated the efficacy of SDC in suspension and the efficacy of SDC and steam vapor against FCV on a glass surface, each with and without serum. Lastly, we tested both technologies on two types of carpet, wool and nylon. Both carpets exhibited no obvious color changes; however, SDC treatments left a residue while steam vapor left minor abrasions to fibers. SDC in suspension and on glass reduced FCV by 4.65 log10and >4.66 log10PFU, respectively, but demonstrated reduced efficacy in the presence of serum. However, SDC was only efficacious against FCV on nylon (3.62-log10PFU reduction) and not wool (1.82-log10PFU reduction). Steam vapor reduced FCV by >4.93 log10PFU on glass in 10 s and >3.68 log10PFU on wool and nylon carpet carriers in 90 s. There was a limited reduction of FCV RNA under both treatments compared to that of infectivity assays, but RNA reductions were higher in samples that contained serum.IMPORTANCEHuman noroviruses (HuNoV) account for ca. 20% of all diarrheal cases worldwide. Disease symptoms may include diarrhea and vomit, with both known to contribute to transmission. The prevention and control of HuNoV are difficult because they are environmentally resilient and resistant to many disinfectants. Several field studies have linked both hard and soft surfaces to HuNoV outbreaks. However, many disinfectants efficacious against HuNoV surrogates are recommended for hard surfaces, but no commercially available products have demonstrated efficacy against these surrogates on soft surfaces. Our research objectives were to evaluate liquid and steam-based technologies in suspension and on hard surface carriers in addition to adapting and testing a protocol for assessing the virucidal effects of disinfection technologies on carpet carriers. These results will inform both the government and industry regarding a standard method for evaluating the virucidal effects of disinfectants on carpet while demonstrating their efficacy relative to suspension and hard-surface tests.

Herbicide selection to terminate grass, legume, and brassica cover crop species

2019 ◽  
Vol 34 (1) ◽  
pp. 48-54
Author(s):  
Kara B. Pittman ◽  
Charles W. Cahoon ◽  
Kevin W. Bamber ◽  
Lucas S. Rector ◽  
Michael L. Flessner
Keyword(s):  
Active Ingredient ◽  
Cover Crops ◽  
Cover Crop ◽  
Field Studies ◽  
Weed Suppression ◽  
Hairy Vetch ◽  
Crop Species ◽  
Rating Data ◽  
Crimson Clover ◽  
And Control

AbstractCover crops provide a number of agronomic benefits, including weed suppression, which is important as cases of herbicide resistance continue to rise. To effectively suppress weeds, high cover crop biomass is needed, which necessitates later termination timing. Cover crop termination is important to mitigate potential planting issues and prevent surviving cover crop competition with cash crops. Field studies were conducted in Virginia to determine the most effective herbicide options alone or combined with glyphosate or paraquat to terminate a range of cover crop species. Results revealed that grass cover crop species were controlled (94% to 98%) by glyphosate alone 4 wk after application (WAA). Overall, legume species varied in response to the single active-ingredient treatments, and control increased with the addition of glyphosate or paraquat. Mixes with glyphosate provided better control of crimson clover and hairy vetch by 7% to 8% compared with mixes containing paraquat 4 WAA. Mix partner did not influence control of Austrian winter pea. No treatment adequately controlled rapeseed in this study, with a maximum of 58% control observed with single active-ingredient treatments and 62% control with mixes. Height reduction for all cover crop species supports visible rating data. Rapeseed should be terminated when smaller, which could negate weed suppressive benefits from this cover crop species. Growers should consider herbicide selection and termination timing in their cover crop plan to ensure effective termination.

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