EFFECTS OF MITICIDES ON THE LIFE STAGES OF THE EUROPEAN RED MITE, PANONYCHUS ULMI (KOCH) (ACARI: TETRANYCHIDAE)

1991 ◽  
Vol 123 (1) ◽  
pp. 77-87 ◽  
Author(s):  
D.B. Marshall ◽  
D.J. Pree

AbstractIn laboratory tests, many miticides affected more than one life stage of the European red mite but most showed greater toxicity to one specific stage. Most were more toxic to nymphs and adults than to eggs. Cyhexatin was more toxic to nymphs whereas fenbutatin-oxide was more toxic to adults than to nymphs. Propargite, formetanate HCl, and dinocap were more toxic to nymphs than to adults. Dicofol and oxythioquinox were more toxic to adults than to nymphs. Dienochlor was the least toxic miticide tested, and was more toxic to nymphs and adults than to eggs. Amitraz, permethrin, and fenpropathrin were repellent to motile stages at low concentrations, but amitraz was also highly ovicidal. Clofentezine and hexythiazox were toxic to eggs and nymphs but not to adults. Affected nymphs developed into the deutochrysalis or teleiochrysalis stages but were unable to eclose from these quiescent stages.In field trials, applications timed to coincide with a predominance of sensitive stages were successful. Early season applications suppressed mite numbers for much of the growing season. Populations exhibiting considerable synchrony occurred into August suggesting that susceptible stages could be targeted for control throughout the season.

1971 ◽  
Vol 103 (12) ◽  
pp. 1663-1669 ◽  
Author(s):  
F. T. Lord

AbstractSix species of predacious Miridae, common to apple trees in Nova Scotia, were used to develop laboratory rearing and feeding techniques for comparing the abilities of predators to consume prey. The test prey species was the European red mite, Panonychus ulmi (Koch), in the winter egg stage. The numbers of eggs consumed per day and per instar in the tests compared favourably with the known predatory values of these mirids under orchard conditions. Both sources of information were used to give the predators a tentative rating. The mirids Hyaliodes harti Knight, Diaphnocoris pellucida (Uhler), Pilophorus perplexus D. and S., and Blepharidopterus angulatus (Fall.) are effective predators, approximately equal to each other in ability to consume the winter eggs of the red mite. The two species Campylomma verbasci (Meyer) and Atractotomus mali (Meyer), which are phytophagous as well as predacious, were less voracious.The results indicate it may be feasible to develop a series of weighting factors, one for each stage of each predacious species, based on ability to consume prey.


Author(s):  
Charlotte Scott

Beginning with an exploration of the role of the child in the cultural imagination, Chapter 1 establishes the formative and revealing ways in which societies identify themselves in relation to how they treat their children. Focusing on Shakespeare and the early modern period, Chapter 1 sets out to determine the emotional, symbolic, and political registers through which children are depicted and discussed. Attending to the different life stages and representations of the child on stage, this chapter sets out the terms of the book’s enquiry: what role do children play in Shakespeare’s plays; how do we recognize them as such—age, status, parental dynamic—and what are the effects of their presence? This chapter focuses on how the early moderns understood the child, as a symbolic figure, a life stage, a form of obligation, a profound bond, and an image of servitude.


Agriculture ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 290
Author(s):  
Koffi Djaman ◽  
Curtis Owen ◽  
Margaret M. West ◽  
Samuel Allen ◽  
Komlan Koudahe ◽  
...  

The highly variable weather under changing climate conditions affects the establishment and the cutoff of crop growing season and exposes crops to failure if producers choose non-adapted relative maturity that matches the characteristics of the crop growing season. This study aimed to determine the relationship between maize hybrid relative maturity and the grain yield and determine the relative maturity range that will sustain maize production in northwest New Mexico (NM). Different relative maturity maize hybrids were grown at the Agricultural Science Center at Farmington ((Latitude 36.69° North, Longitude 108.31° West, elevation 1720 m) from 2003 to 2019 under sprinkler irrigation. A total of 343 hybrids were grouped as early and full season hybrids according to their relative maturity that ranged from 93 to 119 and 64 hybrids with unknown relative maturity. The crops were grown under optimal management condition with no stress of any kind. The results showed non-significant increase in grain yield in early season hybrids and non-significant decrease in grain yield with relative maturity in full season hybrids. The relative maturity range of 100–110 obtained reasonable high grain yields and could be considered under the northwestern New Mexico climatic conditions. However, more research should target the evaluation of different planting date coupled with plant population density to determine the planting window for the early season and full season hybrids for the production optimization and sustainability.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 405
Author(s):  
Miroslav Jursík ◽  
Kateřina Hamouzová ◽  
Jana Hajšlová

(1) Background: Aryloxyphenoxy-propionates and cyclohexanediones are herbicides most widely used in dicot crops worldwide. The main objective of the study was to determine the dynamics of herbicide residues in carrot, lettuce, cauliflower, and onion in order to suggest a low level of residues in harvested vegetables. (2) Methods: Small plot field trials were carried out in four vegetables in the Czech Republic. The samples of vegetables were collected continuously during the growing season. Multiresidue methods for the determination of herbicide residues by LC-MS/MS were used. Non-linear models of degradation of individual herbicides in vegetables were calculated using the exponential decay formula. Action GAP pre-harvest intervals for the 25% and 50% maximum residue limit (MRL) and 10 µg kg−1 limit (baby food) were established for all tested herbicides. (3) Results: The degradation dynamics of fluazifop in carrot, onion, and cauliflower was significantly slower compared to quizalofop and haloxyfop. The highest amount (2796 µg kg−1) of fluazifop residues was detected in cauliflower 11 days after application. No residue of propaquizafop and cycloxydim was detected in any vegetable samples. (4) Conclusions: Aryloxyphenoxy-propionate herbicide (except propaquizafop) could contaminate vegetables easily, especially vegetables with a short growing season. Vegetables treated with fluazifop are not suitable for baby food. Lettuce and cauliflower treated by quizalofop are not suitable for baby food, but in onion and carrot, quizalofop could be used. Propaquizafop and cycloxydim are prospective herbicides for non-residual (baby food) vegetable production.


Biotemas ◽  
2017 ◽  
Vol 30 (1) ◽  
pp. 73
Author(s):  
Cláudia Andréia Gräff ◽  
Liana Johann ◽  
Cláucia Fernanda Volken de Souza ◽  
Noeli Juarez Ferla

http://dx.doi.org/10.5007/2175-7925.2017v30n1p73A vitivinicultura no estado do Rio Grande do Sul tem sofrido infestações significativas de ácaros praga, destacando-se recentemente Panonychus ulmi (Koch). Há relatos sobre a capacidade de controle de ácaros fitófagos com Isaria fumosorosea. O objetivo deste trabalho foi avaliar em laboratório a ação patogênica de I. fumosorosea sobre o ácaro P. ulmi. As criações de P. ulmi foram estabelecidas a partir de coleta realizadas em videiras da Serra Gaúcha. Sobre os ovos de P. ulmi, as aplicações de suspensões de esporos foram feitas em diferentes concentrações. As triplicatas das fêmeas de 12 a 15 dias foram tratadas com suspensão a 108 esporos x mL-1. As testemunhas foram tratadas com água destilada. Após sete dias da aplicação, observaram-se 55,6% de ovos não eclodidos tratados com suspensão 106 esporos x mL-1 e com fêmeas tratadas obteve-se uma mortalidade total entre 85-90% e mortalidade confirmada entre 50-55%. A mortalidade máxima dos controles no tratamento dos ovos e das fêmeas foi, em média, de 12,8 e 15,5%, respectivamente. Conclui-se que o isolado I. fumosorosea possui habilidade para infectar ovos e fêmeas adultas de P. ulmi e portanto mostra-se como uma alternativa viável para ser experimentada no campo.


1962 ◽  
Vol 94 (11) ◽  
pp. 1222-1227 ◽  
Author(s):  
R. S. Downing

In British Columbia the control of phytophagous mites, especially the European red mite, Panonychus ulmi (Koch), and the McDaniel spider mite, Tetranychus mcdanieli McG., is becoming increasingly difficult, mainly because of the mites' ability to develop resistance to most acaricides in a relatively short time (3). Because of this, methods of control other than strictly chemical are examined at every opportunity.


2019 ◽  
Vol 97 (1) ◽  
pp. 35 ◽  
Author(s):  
Víctor Abraham Vargas-Vázquez ◽  
Crystian Sadiel Venegas-Barrera ◽  
Arturo Mora-Olivo ◽  
José Guadalupe Martínez-Ávalos ◽  
Eduardo Alanís-Rodríguez ◽  
...  

<p><strong>Background: </strong>The edge effect differentially affects the species in their life stages. We analyzed the environmental conditions associated with the abundance by life stage of four species of timber trees on the edge of a subdeciduous tropical forest.<strong></strong></p><p><strong>Hypothesis:</strong> The edges have higher light incidence and temperature, favorable conditions for the seedlings, so it is expected that the edge will have more abundance of seedlings with respect to the forest interior.</p><p><strong>Species under study:</strong> <em>Bursera simaruba</em> (L.) Sarg.<em>, Cedrela odorata</em> L.<em>, Guazuma ulmifolia </em>Lam.<em>, Lysiloma divaricatum </em>(Jacq.) J.F. Macbr.</p><p><strong>Study site and dates:</strong> Reserva de la Biosfera "El Cielo" (Tamaulipas), Mexico. January-December 2016.</p><p><strong>Methods: </strong>The abundance by life stages and environmental conditions were quantified within the gradient. These variables were correlated, in addition the requirements between stages were contrasted and they were associated with the identified environments.</p><p><strong>Results:</strong> <em>Guazuma ulmifolia</em> showed a negative response to the edge effect, while <em>Cedrela</em> <em>odorata</em> responded positively. The environmental requirements differed between the first life stages and adults. The abundance of the seedlings was associated to conditions of higher light incidence.</p><strong>Conclusions:</strong> Environmental requirements differentially affect each life stage. The abundance of seedlings increases in conditions of higher light incidence, but not in the rest of the stages, except in <em>C. odorata</em>. The loss of cover and the consequent formation of borders can lead to a reduction in the abundance of these species, with economic implications.


2021 ◽  
pp. jeb.229476
Author(s):  
Yu-Wen Chung-Davidson ◽  
Ugo Bussy ◽  
Skye D. Fissette ◽  
Anne M. Scott ◽  
Weiming Li

Pheromonal bile salts are important for sea lampreys (Petromyzon marinus Linnaeus) to complete their life cycle. The synthesis and release of a releaser/primer pheromone 3-keto petromyzonol sulfate (3kPZS) by spermiating males have been well characterized. 3kPZS evokes sexual behaviors in ovulatory females, induces immediate 3kPZS release in spermiating males, and elicits neuroendocrine responses in prespawning adults. Another primer pheromone released by spermiating males, 3-keto allocholic acid (3kACA), antagonizes the neuroendocrine effects of 3kPZS in prespermiating males. However, the effects of 3kACA and 3kPZS on pheromone production in prespawning adults is unclear. To understand the foundation of pheromone production, we examined sea lamprey bile salt levels at different life stages. To investigate the priming effects of 3kACA and 3kPZS, we exposed prespawning adults with vehicle or synthetic 3kACA or 3kPZS. We hypothesized that endogenous bile salt levels were life-stage and sex-dependent, and differentially affected by 3kACA and 3kPZS in prespawning adults. Using ultra-performance liquid chromatography tandem mass spectrometry, we found that sea lampreys contained distinct mixtures of bile salts in the liver and plasma at different life stages. Males usually contained higher amounts of bile salts than females. Petromyzonamine disulfate was the most abundant C27 bile salt and petromyzonol sulfate was the most abundant C24 bile salt. Waterborne 3kACA and 3kPZS exerted differential effects on bile salt production in the liver and gill, their circulation and clearance in the plasma, and their release into water. We conclude that bile salt levels are life-stage and sex-dependent and differentially affected by primer pheromones.


2019 ◽  
Vol 8 (2) ◽  
pp. 20
Author(s):  
Heli I. Koskinen

Larsen, Nansen, Gr&ouml;nvold, Wolstrup and Henriksen (1997) have previously reviewed the prospects of control of equine nematodes by using fungal cultures. Since then more investigations have been implemented and actualized. Field trials and laboratory tests have been reported with new perspectives and increasing number of animals in trials. The aim of this new review of literature is to add new knowledge to those questions that remained open in the 1990s. In particular, on the perspective of veterinary practitioner and sustainable use of deworming practices it is important to know those directions which should be followed.


Sign in / Sign up

Export Citation Format

Share Document