Control of cabbage stem weevil and pollen beetle with one insecticide application

Over the course of three years (2016–2018), the effects of insecticides on stem-mining weevils [(Ceutorhynchus pallidactylus (Marsham, 1802), Ceutorhynchus napi (Gyllenhal, 1837)] were assessed under field conditions. The dates for spraying were determined on the basis of the recorded percentages of weevil females carrying mature eggs in their ovaries (timing I: the first females with mature eggs present in yellow water traps; timing II: more than 50% of the females with mature eggs present). Delaying the first spring insecticide application till timing II made it possible to combine the control of the stem weevil along with the control of the pollen beetle, Brassicogethes aeneus (Fabricius, 1775). However, the poor effectiveness of the tested insecticides on the stem-mining weevils, regardless of the date they were sprayed, indicates it is impossible to successfully control the insect pests with one insecticide application during the seasons with prolonged egg-laying periods.

Download Full-text

Spatio-temporal Distributions and Associations of Cabbage Stem Weevil (Ceutorhynchus Pallidactylus Marsham, 1802) and Pollen Beetle (Brassicogethes Aeneus Fabricius, 1775) in winter oilseed rape

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201765030839 ◽

2017 ◽

Vol 65 (3) ◽

pp. 839-847

Author(s):

Vojtěch Hlavjenka ◽

Marek Seidenglanz ◽

Jaroslav Šafář

Keyword(s):

Oilseed Rape ◽

Cumulative Distribution ◽

Winter Oilseed Rape ◽

High Tendency ◽

Pollen Beetle ◽

Brassicogethes Aeneus ◽

Males And Females ◽

Spatio Temporal ◽

The Individual ◽

Ceutorhynchus Pallidactylus

From 2013 to 2015 the within-field spatio-temporal distributions and interactions between Ceutorhynchus pallidactylus and Brassicogethes aeneus in winter oilseed rape crops were assessed using SADIE analysis (Spatial Analysis by Distance IndicEs) and Quick association analysis. A significant tendency for aggregation was recorded in C. pallidactylus males in the crop in both 2013 and 2015. Females showed a high tendency towards aggregation only in 2013. Both sexes were significantly associated in crops in 2013 and 2015. B. aeneus adults showed a high tendency towards aggregation in all three years. From the three seasons the cumulative distributions (based on the sums of insect catches in traps for the individual dates) of males and females of C. pallidactylus were significantly associated with the cumulative distribution of B. aeneus adults only in 2013. Contrary to this, an almost significant dissociation between cumulative distributions of C. pallidactylus males and B. aeneus adults was recorded in 2014.

Download Full-text

The importance of monitoring the Ceutorhynchus pallidactylus female flight activity for the timing of insecticidal treatment

Plant Protection Science ◽

10.17221/37/2008-pps ◽

2009 ◽

Vol 45 (No. 3) ◽

pp. 103-112 ◽

Cited By ~ 4

Author(s):

M. Seidenglanz ◽

E. Poslušná J Hrudová

Keyword(s):

Czech Republic ◽

Flight Activity ◽

Field Conditions ◽

Substantial Proportion ◽

The Czech Republic ◽

Water Traps ◽

Insecticidal Treatment ◽

Ceutorhynchus Pallidactylus

The effects of two pyrethroids and one combination of organophosphate and pyrethroid (alpha-cypermethrin, etofenprox, chlorpyrifos + cypermethrin) on Ceutorhynchus pallidactylus (Marsham, 1802) (Coleoptera: Curculionidae) were tested under field conditions in the Czech Republic in 2006–2008. Significant differences in the effects of the compared insecticides on C. pallidactylus were recorded in the particular years (2006, 2007, 2008). It was less important and somewhat less complicated to establish the most suitable time for spraying in the case of the chlorpyrifos + cypermethrin combination in comparison with the pyrethroids applied separately. The effectiveness of the tested insecticides was markedly influenced by the time of spraying. The effects of the pyrethroids applied singly achieved results comparable to those of the chlorpyrifos + cypermethrin combination only at the optimal spraying time. The most suitable time for spraying varied from the point when the first females appeared in yellow water traps in somewhat higher quantities to the time when a substantial proportion of caught females was able to lay eggs.

Download Full-text

Phenology and suppression of stem weevils (Ceutorhynchus napi gyllenhal and Ceutorhynchus pallidactylus marsham) in oilseed rape in northern Serbia

Pesticidi i fitomedicina ◽

10.2298/pif1804213s ◽

2018 ◽

Vol 33 (3-4) ◽

pp. 213-220

Author(s):

Lazar Sivcev ◽

Ivan Sivcev ◽

Draga Graora ◽

Snezana Pesic ◽

Vladimir Tomic ◽

...

Keyword(s):

Oilseed Rape ◽

Stem Elongation ◽

Early Spring ◽

Insecticide Treatment ◽

Brassicogethes Aeneus ◽

New Findings ◽

Main Period ◽

Ceutorhynchus Napi ◽

Ceutorhynchus Pallidactylus ◽

New Generation

Stem weevils (Ceutorhynchus pallidactylus and Ceutorhynchus napi) are significant pests of oilseed rape that farmers regularly suppress by insecticide treatments intended against Brassicogethes aeneus. Recent studies have shown that in some regions of northern Serbia C. napi is dominant, while C. pallidactylus prevails in others. Increased damage from stem weevils has elicited an exploration of the situation and a study of their phenology and effects of insecticides in three differently managed fields: conventional, organic and integrated. New findings regarding the phenology of stem weevils show that both species were sporadically present in our experimental oilseed rape fields as early as during autumn (from the end of October 2010, BBCH 17-18). The main period of stem weevil settlement is the end of winter and early spring. Maximum flight of both weevil species was recorded on March 23 at the beginning of oilseed rape (OSR) stem elongation (BBCH 22-25), and one week later in the organic field. There were no significant differences in the number of settled weevils among the three differently managed fields. The insecticide treatment against C. napi was applied two weeks earlier than the usual treatment against B. aeneus and C. pallidactylus. Thus, it is clear that insecticide treatment directed against B. aeneus and C. pallidactylus is not effective against C. napi. In this way, such a practice can contribute to an increase in OSR damage, and density of the next generation of C. napi. A new generation of C. pallidactylus emerged from OSR fields in June 2011, while the majority of C. napi emerged in March of the following year.

Download Full-text

Suppression of Rice Planthopper Populations by the Entomopathogenic Fungus Metarhizium anisopliae without Affecting the Rice Microbiota

Applied and Environmental Microbiology ◽

10.1128/aem.01337-20 ◽

2020 ◽

Vol 86 (21) ◽

Author(s):

Yifan Peng ◽

Jifeng Tang ◽

Mingsheng Hong ◽

Jiaqin Xie

Keyword(s):

Microbial Communities ◽

Entomopathogenic Fungi ◽

Metarhizium Anisopliae ◽

Insect Pests ◽

Fungal Strain ◽

Field Conditions ◽

Content Type ◽

Insecticide Application ◽

Rice Planthoppers ◽

Good Potential

ABSTRACT Entomopathogenic fungi can regulate insect populations and function as crucial biological control agents against insect pests, but their impacts on nontarget microorganisms are poorly understood. In this study, we investigated the potential of the fungal strain Metarhizium anisopliae CQMa421 to control rice planthoppers under field conditions and its effects on rice microbiota. This fungus suppressed rice planthoppers during this period, and its control efficiency was more than 60% 7 days after application and did not significantly differ from that of the chemical treatment except in 2019. Both treatments showed a smaller population of rice planthoppers than the controls. After application, M. anisopliae was maintained on rice plants for approximately 14 days, showing a decreasing trend over time. Furthermore, the results showed that the bacterial and fungal richness (operational taxonomic units) and diversity (Shannon index) did not significantly differ between the fungal treatment and the controls after application. The major bacterial taxa of Proteobacteria (including Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria), Actinobacteria, Bacteroidetes, and Cyanobacteria accounted for more than 80% of the bacterial community after fungal application, and the major fungal taxa Ascomycota (including Eurotiomycetes, Dothideomycetes, and Sordariomycetes) and Basidiomycota (including Ustilaginomycetes) represented more than 90% of the fungal community. However, the microbial communities of the rice phyllosphere did not significantly change after entomopathogenic-agent application, indicating that the indigenous microbial communities may adapt to fungal insecticide application. Taken together, the results suggest that this fungal agent has good potential for rice planthopper control with no substantial effects on rice microbial communities. IMPORTANCE Entomopathogenic fungi may be used as crucial biocontrol agents for the control of insect pests, but few effective fungal strains have been reported for the control of the rice planthopper, a major pest of rice. More importantly, the impacts of fungal insecticide application on nontarget microorganisms have not been well evaluated, especially under field conditions. Therefore, in this study, we investigated the effects of the fungal strain M. anisopliae CQMa421 on rice planthopper populations from 2017 to 2019 and evaluated its potential impacts on the microbiota of rice plants after application. The results suggested that this fungal agent has good potential for use in the control of rice planthoppers with no significant effects on rice microbial communities, representing an alternative strategy for the control of rice pests.

Download Full-text

Effects of insecticide application on parasitism rates of pollen beetle larvae (Brassicogethes aeneus (Fabricius)) by tersilochine parasitoids

Arthropod-Plant Interactions ◽

10.1007/s11829-017-9580-y ◽

2017 ◽

Vol 12 (6) ◽

pp. 799-809 ◽

Cited By ~ 2

Author(s):

Meike Brandes ◽

Udo Heimbach ◽

Bernd Ulber

Keyword(s):

Pollen Beetle ◽

Insecticide Application ◽

Brassicogethes Aeneus ◽

Parasitism Rates

Download Full-text

The effect of insecticide application by dropleg sprayers on pollen beetle parasitism in oilseed rape

BioControl ◽

10.1007/s10526-021-10111-9 ◽

2021 ◽

Author(s):

Johannes Hausmann ◽

Udo Heimbach ◽

Michael Rostás ◽

Meike Brandes

Keyword(s):

Oilseed Rape ◽

Insect Pests ◽

Biological Control Agent ◽

Control Agent ◽

Total Catch ◽

Pollen Beetle ◽

Brassicogethes Aeneus ◽

Larval Parasitoid ◽

Parasitism Rates ◽

The Impact

AbstractDropleg sprayers apply pesticides below the flower horizon of oilseed rape plants and thus reduce unwanted side effects on pollinating insects. Whether this technique benefits parasitoids of seed and pollen feeding insect pests has not been studied earlier. To answer this question, we first assessed the vertical distribution of pests and parasitoids using a portable aspirator. In addition, parasitism rates of pollen beetle, Brassicogethes aeneus Fabricius (Coleoptera: Nitidulidae), by the larval parasitoid Tersilochus heterocerus Thomson (Hymenoptera: Ichneumonidae) were compared in conventional and dropleg sprayed fields over four years (2016–2019), using the neonicotinoids thiacloprid and acetamiprid. Our results show that seed and pollen feeders were mainly found in the flowering canopy, while the predominant location of parasitoids was species-specific. Among pollen beetle parasitoids, Phradis interstitialis Thomson (Hymenoptera: Ichneumonidae) was more abundant below flowering canopy (63% of total catch), whereas T. heterocerus was mainly caught in the flowering canopy (84% of total catch). In the spraying experiments, average parasitism rates of pollen beetles by T. heterocerus ranged between 55 and 82% in the untreated controls. In the dropleg spray treatments, parasitism rates did not differ significantly from control levels, with the exception of thiacloprid application in 2019. In contrast, conventional spray applications resulted in a reduction of parasitism rates by up to 37% compared to the control for at least one of the insecticides in three out of four years. The impact of conventional application differed between years, which may be explained by the temporal coincidence between spray application and the immigration of parasitoids into the crop. We conclude that dropleg spraying exerts lower non-target effects on the main biological control agent of pollen beetle.

Download Full-text

RNAi efficacy is enhanced by chronic dsRNA feeding in pollen beetle

Communications Biology ◽

10.1038/s42003-021-01975-9 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Jonathan Willow ◽

Liina Soonvald ◽

Silva Sulg ◽

Riina Kaasik ◽

Ana Isabel Silva ◽

...

Keyword(s):

Rna Interference ◽

Pest Management ◽

Oilseed Rape ◽

Growth Stages ◽

Short Term ◽

Pollen Beetle ◽

Brassicogethes Aeneus ◽

Crop Growth Stages ◽

Insecticidal Compounds ◽

Significant Mortality

AbstractDouble-stranded RNAs (dsRNAs) represent a promising class of biosafe insecticidal compounds. We examined the ability to induce RNA interference (RNAi) in the pollen beetle Brassicogethes aeneus via anther feeding, and compared short-term (3 d) to chronic (17 d) feeding of various concentrations of dsRNA targeting αCOP (dsαCOP). In short-term dsαCOP feeding, only the highest concentration resulted in significant reductions in B. aeneus survival; whereas in chronic dsαCOP feeding, all three concentrations resulted in significant mortality. Chronic dsαCOP feeding also resulted in significantly greater mortality compared to short-term feeding of equivalent dsαCOP concentrations. Our results have implications for the economics and development of dsRNA spray approaches for managing crop pests, in that multiple lower-concentration dsRNA spray treatments across crop growth stages may result in greater pest management efficacy, compared to single treatments using higher dsRNA concentrations. Furthermore, our results highlight the need for research into the development of RNAi cultivars for oilseed rape protection, given the enhanced RNAi efficacy resulting from chronic, compared to short-term, dsRNA feeding in B. aeneus.

Download Full-text