scholarly journals High Tolerance of Trichogramma Pretiosum (Hymenoptera: Trichogrammatidae) to the Mixture of the Herbicides Nicosulfuron Plus Atrazine

2020 ◽  
Author(s):  
Germano Leão Demolin Leite ◽  
João Marcos Batista Cordeiro ◽  
Leonardo David Tuffi Santos ◽  
Wagner de Souza Tavares ◽  
Alexandre Igor de Azevedo Pereira ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Free Choice ◽  
Integrated Control ◽  
The Other ◽  
Choice Test ◽  
Trichogramma Pretiosum ◽  
Maize Crop ◽  
Trichogramma Brasiliensis ◽  
Herbicide Mixture ◽  
Lepidopteran Pest

Abstract Background: Maize, Zea mays (Poaceae), is one of the most important crops in the world, but defoliating caterpillars (Lepidoptera) and weeds can reduce the productivity of this plant. The control of weeds in the maize crop in Brazil is mainly accomplished with nicosulfuron- and atrazine-based herbicides, and of lepidopteran pest eggs with use of several species of Trichogrammatidae (Hymenoptera) parasitoids released. The objective of this study was to evaluate the rates of parasitism and emergence of females and the sex ratio (%) of 10 Trichogrammatidae species, in a free-choice test, submitted to a mixture of the herbicides Sanson 40 SC® (a.i. nicosulfuron; dose: 30 g.ha–1) + Gesaprim 500 Ciba-Geigy® (a.i. atrazine; dose: 1500 g.ha–1) in the laboratory.Results: The parasitism rate (%) of Trichogramma acacioi Brun, Moraes & Soares, Trichogrammatoidea annulata de Santis, Trichogramma atopovirilia Oatman & Platner, Trichogramma bennetti Nagaraja & Nagarkatti, Trichogramma brunni Nagaraja, Trichogramma brasiliensis Ashmead, Trichogramma demoraesi Nagaraja, Trichogramma galloi Zucchi, and Trichogramma soaresi Nagaraja was lower with the herbicide mixture of nicosulfuron + atrazine than the control and, therefore, this mixture was considered to be slightly harmful (i.e., class II of the International Organization for Biological and Integrated Control) to these parasitoids. This solution reduced the emergence rate (%) of female T. acacioi, T. annulata, T. atopovirilia, T. bruni, T. brasiliensis, T. demoraesi, T. galloi, and T. soaresi, being classified as harmless to T. soaresi, moderately harmful to T. galloi and slightly harmful to the other species. The herbicide mixture of nicosulfuron + atrazine reduced the sex ratio of T. acacioi, T. atopovirilia, T. bruni, T. demoraesi, T. galloi, and T. soaresi, being classified as harmless to T. annulata and T. brasiliensis, and slightly harmful to the other species.Conclusions: The biological parameters (i.e., rates of parasitism and emergence and the sex ratio) of T. pretiosum, followed by T. bennetti, T. annulata and T. brasiliensis were the least affected by the herbicide mixture. These species should be chosen for release, on pieces of paperboard with parasitized E. kuehniella eggs, in crops together with the application of nicosulfuron + atrazine.

scholarly journals Study of Host Preference and the Comparison of some Biological Characteristcs of Bemisia Tabasi (Genn) on Tomato Varieties

2013 ◽  
Vol 53 (2) ◽  
pp. 137-142
Author(s):  
Masoomeh Samareh Fekri ◽  
Mohammad Amin Samih ◽  
Sohrab Imani ◽  
Mehdi Zarabi
Keyword(s):  
Free Choice ◽  
Host Preference ◽  
Resistance Mechanism ◽  
Total Mortality ◽  
Statistical Design ◽  
The Other ◽  
Choice Test ◽  
Percentage Mortality ◽  
Tomato Variety ◽  
Choice Preference

Abstract The resistance of 8 tomato varieties to cotton white fly, Bemisia tabaci (Genn) (Hemiptera: Aleyrodidae), was evaluated in four greenhouse experiments. In the first experiment, we evaluated the attractiveness and preference for oviposition in a free-choice test (randomized blocks, 8 treatments, and 5 replications). In the other experiments, we evaluated the no-choice preference for oviposition (randomized blocks, 4 treatments, and 4 replications). The whitefly egg-adult cycle was monitored using a statistical design in randomized blocks with four replications. The percentage mortality of immature stages was also determined (randomized blocks with four replications). In the free-choice test, the tomato variety Rio Grande was the most attractive to adults, while the variety Cheffalat had the lowest number of adults. Also in this assay, the variety CAL-JN3 presented the lowest number of eggs, while the variety Ergon presented the highest number of eggs. In the no-choice test, the varieties Chef-falat and CAL-JN3 remained resistant. Consequently, for these two varieties non-preference is the oviposition resistance mechanism. The egg-adult cycle varied from 26.02 days (Ergon) to 26.66 days (CAL-JN3). The total mortality varied from 20.52 (Ergon) to 33.97 (CAL-JN3). Considering all the characteristics, the variety CAL-JN3 was the most resistant to B. tabaci among all the tomato varieties studied, while variety Ergon was susceptible.

scholarly journals Lethal, Sublethal And Transgenerational Effects of Insecticides Labeled For Cotton On Immature Trichogramma Pretiosum

2021 ◽  
Author(s):  
Mariana Abreu Costa ◽  
Elizeu Sá Farias ◽  
Eliana Donizete Andrade ◽  
Vinícius Castro Carvalho ◽  
Geraldo Andrade Carvalho
Keyword(s):  
Sex Ratio ◽  
Adult Emergence ◽  
Positive Control ◽  
Egg Parasitoid ◽  
Biological Traits ◽  
Trichogramma Pretiosum ◽  
Transgenerational Effects ◽  
Female Survival ◽  
Chemical Groups ◽  
Lepidopteran Pest

Abstract The egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) regulates lepidopteran pest populations in cotton crops. However, cotton harbors dozens of pests, and growers rely on multiple insecticide applications to manage these damaging organisms. A harmonious integration of control tactics is required for proper pest management, and the use of selective insecticides (i.e., those promoting effective pest control while causing little impact on natural enemies) fits within this scope. This study aimed to assess the lethal, sublethal and transgenerational effects of insecticides from varying chemical groups on T. pretiosum. The insecticides were sprayed on parasitized host [Ephestia kuehniella (Zeller)] eggs with developing T. pretiosum stages (egg-larva, prepupa and pupa), and biological traits were assessed following adult emergence. Overall, pupae were more susceptible to the insecticides. We found thiodicarb and chlorfenapyr to reduce F0 adult emergence in rates comparable to the positive control (methomyl). Adult F0 deformation was the highest on flupyradifurone-treated organisms, and both the F0 parasitism rate and female survival were reduced by the insecticides (except for teflubenzuron). The sex ratio was affected by thiodicarb and flupyradifurone. Transgenerational effects occurred on adult emergence, which was reduced on the offspring (F1) of thiodicarb-, chlorfenapyr-, and flupyradifurone-treated T. pretiosum. In addition, thiodicarb lessened the F1 sex ratio. Combined, these results indicate that teflubenzuron is the safest insecticide; the other insecticides (especially thiodicarb and chlorfenapyr) are non-selective to T. pretiosum. Field and semifield studies are required to confirm the harmfulness of thiodicarb and chlorfenapyr towards T. pretiosum.

Effect of Propofol on Affective State as Assessed by Place Conditioning Paradigm in Rats

1996 ◽  
Vol 85 (1) ◽  
pp. 121-128 ◽  
Author(s):  
L. Pain ◽  
P. Oberling ◽  
G. Sandner ◽  
G. Di Scala
Keyword(s):  
Free Choice ◽  
Recovery Period ◽  
Affective State ◽  
Conditioning Session ◽  
Place Preference ◽  
The Other ◽  
Choice Test ◽  
Place Conditioning ◽  
Short Term ◽  
Conditioning Paradigm

Background Whether propofol produces a pleasant affective state remains unclear from clinical studies. In the current study, the effect on affective state of subanesthetic and anesthetic doses of propofol was assessed at a preclinical level with rats in a place conditioning paradigm. Propofol was compared with methohexital. Methods In the place conditioning paradigm, propofol-induced effect was repeatedly paired with one of two distinguishable compartments of the apparatus, whereas the vehicle-induced effect was repeatedly paired with the other compartment. During a subsequent free-choice test, a preference for the drug-paired compartment over the vehicle-paired compartment would be indicative of pleasant state induced by the drug. For all experiments, the conditioning session lasted 8 days and consisted of four pairings of the drug with one compartment and four pairings of the equivalent volume of vehicle with the other compartment. In experiment 1A, four groups of rats were designated according to the dose of propofol that they received intraperitoneally: 0,30,60, or 90 mg/kg. In experiment 1B, the same procedure was used with subanesthetic doses of intraperitoneal methohexital: 0,10,20, or 30 mg/kg. In experiment 2, the rats were conditioned during the recovery period from short-term anesthesia. For one group, anesthesia was induced by propofol (100 mg/kg) whereas for the other group, anesthesia was induced by an equivalent anesthetic dose of methohexital (40 mg/kg). Results In experiment 1A, the 30-mg/kg, 60-mg/kg, and 90-mg/kg groups showed a place preference for the drug-paired compartment, but only the group conditioned with 60 mg/kg propofol significantly differed from the 0-mg/kg group. In experiment 1B, the groups conditioned with methohexital showed no place preference for the drug-paired compartment. In experiment 2, the rats showed a place preference for the compartment in which they recovered from propofol-induced anesthesia but no place preference for the compartment in which they recovered from methohexital-induced anesthesia. Conclusions Propofol, but not methohexital, induced a pleasant affective state in rats at subanesthetic doses as well as during recovery from an anesthetic dose.

scholarly journals Do fall armyworm’s Metaflumizone resistante populations affect the activity of Trichogramma pretiosum?

2023 ◽  
Vol 83 ◽  
Author(s):  
M. G. Barbosa ◽  
S. A. Souza ◽  
T. P. P. André ◽  
A. D. S. Pontes ◽  
C. S. Teixeira ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Spodoptera Frugiperda ◽  
Free Choice ◽  
Experimental Unit ◽  
Trichogramma Pretiosum ◽  
Resistant Population ◽  
Randomized Experimental Design ◽  
Choice Testing ◽  
Lepidoptera Noctuidae ◽  
Two Populations

Abstract The possible interference of resistant pest’s populations to insecticides in natural enemies in the action thas not been clarified yet. Thus, this study aimed to evaluate Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) performance on Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) eggs with resistance frequency to the Metaflumizone over six generations of product exposure. Egg cards (2.0 x 7.0 cm) containing eggs from two populations of S. frugiperda, (resistant to Metaflumizone and the other susceptible), were exposed to T. pretiosum females for 24 hours in free-choice and no-choice testing in three generations (G1, G4, and G6). A completely randomized experimental design was used with 25 replications, each consisting of an egg card (experimental unit) containing 20 eggs. The parameters evaluated were: parasitism (%), emergence (%), sex ratio, number of emerged parasitoids per egg and males/females longevity. ANOVA and Tukey test (P≤ 0.05) were applied on the results. Results showed a reduction in parasitism [41.0% (G1) and 28.4% (G4)], egg emergence (17.5%) and parasitoids/egg [16.2 (G4) and 17.2 (G6)] in eggs originating from the population with resistance frequency. Females emerging from G6 populations eggs without exposure to Metaflumizone had greater longevity (3.5 days more) than the resistant population. The sex ratio and male longevity were not affected. The results indicate a reduction in T. pretiosum activity if S. frugiperda populations have some frequency of resistance to Metaflumizone.

A glyphosate-based herbicide in a free-choice test on parasitism, emergence, and female-biased sex ratio of 10 Trichogrammatidae

2019 ◽  
Vol 127 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Jonas Pereira Pontes ◽  
Germano Leão Demolin Leite ◽  
Edilson Paulo Rodrigues Bispo ◽  
Wagner de Souza Tavares ◽  
Claubert Wagner Guimarães de Menezes ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Free Choice ◽  
Choice Test ◽  
Biased Sex Ratio

scholarly journals Toxicological and behavioral impacts of atrazine on Trichogrammatidae (Hymenoptera) in choice tests

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Germano Leão Demolin Leite ◽  
Edilson Paulo Rodrigues Bispo ◽  
Anarelly Costa Alvarenga ◽  
Paula Daiana De Paulo ◽  
Marcus Alvarenga Soares ◽  
...  
Keyword(s):  
Natural Enemies ◽  
Free Choice ◽  
Test Tube ◽  
The Other ◽  
Choice Test ◽  
Choice Tests ◽  
Herbicide Atrazine ◽  
Lepidoptera Pyralidae ◽  
Glass Test Tube ◽  
And Control

Weeds should be controlled with low impact methods and selective agrochemicals that have little or no effect on non-target organisms. This study aimed to evaluate the effect of the herbicide atrazine (triazine class) on 10 Trichogrammatidae (Hymenoptera) species. A female of 10 species of these natural enemies was individually placed in a glass test tube (free-choice test) with two paper cards containing 45 Anagasta (Ephestia) kuehniella (Lepidoptera: Pyralidae) eggs (treatment and control), with 10 replications. The cards were sprayed with the herbicide atrazine at 8.07 L/ha; the control was sprayed with distilled water. Parasitism by these natural enemies was allowed for 48 h. Atrazine changes the behavior of female parasitoids, reducing the parasitism (≈ 71 %) and emergence (≈ 74 %) rates and sex ratio (≈ 74 %) of the Trichogrammatidae species, except for Trichogramma galloi and T. bennetti. No females emerged from eggs parasitized by T. acacioi, Trichogrammatoidea annulata, T. atopovirilia, T. bruni, T. brasiliensis, T. demoraesi, and T. soaresi with atrazine. The results revealed that atrazine herbicide is harmless to T. bennetti and T. galloi, but it was moderately harmful (80 – 99 % reduction) to the other Trichogrammatidae species based on the parasitism and emergence rates.

scholarly journals Seletividade de agrotóxicos recomendados na produção integrada da maçã a Trichogramma pretiosum Riley, 1879 (Hym.: Trichogrammatidae) em condições de laboratório

2006 ◽  
Vol 28 (2) ◽  
pp. 254-257 ◽  
Author(s):  
Cristiane Gindri Manzoni ◽  
Anderson Dionei Grützmacher ◽  
Fabrizio Pinheiro Giolo ◽  
Crislaine Alves Barcellos de Lima ◽  
Sandro Daniel Nörnberg ◽  
...  
Keyword(s):  
Integrated Control ◽  
International Organization ◽  
Trichogramma Pretiosum

A seletividade de oito agrotóxicos recomendados na Produção Integrada da Maçã (PIM) foi avaliada sobre Trichogramma pretiosum Riley em laboratório, utilizando-se da metodologia padronizada pela International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Os produtos (% da formulação comercial na calda) Captan 500 PM (0,240) e Delan (0,125) foram inócuos; Promalin (9,000) foi levemente nocivo; Assist (4,000) e Dormex (1,200) foram moderadamente nocivos; Vertimec 18 CE (0,100), Malathion 1000 CE (0,100) e Supracid 400 CE (0,100) foram nocivos a adultos de T. pretiosum no teste de toxicidade em laboratório. Os agrotóxicos classificados como moderadamente nocivos e nocivos requerem testes subseqüentes de persistência biológica do produto em casa de vegetação e de campo.

The effect of leguminous plant species onCallosobruchus maculatus(Coleoptera: Bruchidae) and its egg parasitoidUscana lariophaga(Hymenoptera: Trichogrammatidae)

1998 ◽  
Vol 88 (1) ◽  
pp. 93-99 ◽  
Author(s):  
A. van Huis ◽  
M. de Rooy
Keyword(s):  
Sex Ratio ◽  
Plant Species ◽  
Nutritional Quality ◽  
Development Time ◽  
Callosobruchus Maculatus ◽  
Egg Parasitoid ◽  
The Other ◽  
Leguminous Plant ◽  
Trade Off ◽  
Storage Pest

AbstractThe performance of the egg parasitoidUscana lariophagaSteffan was studied when reared on eggs of the bruchid storage pest,Callosobruchus maculatus(Fabricius) developing in seeds of cowpea, chickpea and pigeonpea. The beetle laid more and larger eggs on pigeonpea than on cowpea and chickpea, indicating that there was not a trade-off between number and size of the eggs. The bruchid larvae reared on pigeonpea exhibited a longer development time and a higher mortality than those reared on cowpea and chickpea. The resulting males weighed less than those reared on cowpea and chickpea. The trichogrammatidU. lariophagaparasitized more eggs whenC. maculatuswas reared on chickpea than when reared on the other hosts. Parasitoid larvae developed slowest and had the highest mortality in eggs ofC. maculatusreared on pigeonpea compared to those reared on cowpea and chickpea; the sex ratio (% of females) of the resulting adults was also higher. The high mortality and long development time ofC. maculatusreared on pigeonpea indicated that this legume was less favourable toC. maculatusthan chickpea or cowpea. This was probably also true for the parasitoid since the mortality was higher and development longer in eggs ofC. maculatusreared on pigeonpea compared to those reared on cowpea and chickpea. Therefore, when host eggs were larger and of lower nutritional quality, the proportion of female egg parasitoids was greater.

Headless Relative Clauses in K'iche'

2021 ◽  
pp. 260-289
Author(s):  
Telma Angelina Can Pixabaj
Keyword(s):  
Relative Clauses ◽  
Free Choice ◽  
The Other ◽  
Free Relative ◽  
Preliminary Description

This chapter offers a preliminary description of headless relative clauses in K’iche’. The language exhibits all three varieties of free relative clauses that are attested crosslinguistically: maximal, existential, and free-choice. It also has two other kinds of headless relative clauses: light-headed relative clauses introduced by determiners (without wh-expressions) and headless relative clauses with no marking of any kind (neither wh-expressions nor determiners). Overall, the picture that emerges is that all three varieties of free relative clauses exhibit clear morpho-syntactic and semantic differences that differentiate them both from each other as well as from headed relative clauses. One characteristic that helps to differentiate between them is the different subsets of wh-expressions they make use of. All of these wh- clausal constructions are related but, crucially, independent. Of the two kinds of headless relative clauses that do not make use of wh-expressions, one kind—light-headed relative clauses—is introduced by a determiner, while the other kind has no special marking. Both exhibit distributional and semantic restrictions that distinguish them from headed relative clauses.

Unequal sex ratios in longline catches

2001 ◽  
Vol 81 (1) ◽  
pp. 187-188 ◽  
Author(s):  
P. Wirtz ◽  
T. Morato
Keyword(s):  
Sex Ratio ◽  
Feeding Behaviour ◽  
Sex Ratios ◽  
The Other ◽  
Size Difference ◽  
Longline Fishery ◽  
Significant Bias ◽  
Different Response ◽  
The Given

There is sometimes a significant bias in the sex ratio of fish caught by longline. Usually, more females than males are caught. The possible reasons for unequal sex ratios in longline catches are listed and discussed. One sex could be more common in the area where the fishery takes place because there really is an unequal sex ratio in the population or because the other sex preferentially occurs in different places. Alternatively, longline fishery might preferentially catch one of the sexes. This could be a result of size difference between the sexes and thus a different response to the given hook size or bait size. Finally, sexes could differ in their feeding behaviour. There is growing evidence that females—not only of fish—are ‘energy maximizers’: they find food faster and spend more time feeding than do males. Thus, fishing methods using bait are likely to catch a higher proportion of females than fishing methods that do not use bait.

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