field population
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2023 ◽  
Vol 83 ◽  
Author(s):  
Z. Javed ◽  
M. S. Asim ◽  
A. R. Ishaq ◽  
T. Younis ◽  
M. Manzoor ◽  
...  

Abstract Development of insecticides resistance mainly hinge with managements techniques for the control of Jassid, Amrasca biguttutla biguttutla. Five insecticides were applied against field collected and laboratory rared jassid populations during the years of 2017 to 2019 to profile their resistance level against field population of jassid through leaf dip method. Very low resistance level was found in jassid against confidor whereas high level of resistance was observed by pyriproxyfen against other test insecticides. Gradual resistance was observed against diafenthiuron. It is concluded that for the management of Jassid repetition of same insecticide should be avoided. The use of confidor may be reduced to overcome resistance against Jassid.


Author(s):  
Huihua Hao ◽  
Peizheng Li ◽  
Tianwei Xu ◽  
Qiqi Wu ◽  
Fangping Zhang ◽  
...  

In this study, we aimed to clarify the effect of predatory mites on controlling the rubber tree pest mite Eotetranychus sexmaculatus (Riley) and explored basic application of the biocontrol technology “using predatory mites to control pest mites” to rubber trees. We selected two commercial species with high predation capacity from five species of predatory mites for further field-release tests. The results showed that among the five predatory mite species, Phytoseiulus persimilis (Athias‐Henriot) and Neoseiulus cucumeris (Oudemans) showed the highest and lowest daily average predation amounts on E. sexmaculatus, respectively, and that the commercial predatory mites Amblyseius swirskii (Athias‐Henriot) and Neoseiulus barkeri (Hughes) were demonstrated relatively high predation capacities on E. sexmaculatus and represent the ideal species for field release. Additionally, we found that field release by a hanging release sachet was suitable for a low field-population density of pest mites, and that predatory mites could be released at a dose of one sachet per tree and/or every other row or every other tree according to the actual situation of the pest mites. If the field population of E. sexmaculatus is at the peak egg-laying period, the release of A. swirskii should be top priority, which will lead to high control efficiency within 2 to 3 weeks. In case of low field-population density of E. sexmaculatus or a rainy season, top priority should be given to the release of N. barkeri, which might lead to high control efficiency within 3 to 4 weeks. The results showed that the release of A. swirskii had a more fast-acting effect with a higher control efficiency than N. barkeri at the early stage of release, whereas N. barkeri exhibited a better release effect with greater persistence than A. swirskii at the late stage of release.


2021 ◽  
Vol 28 (4) ◽  
pp. 293-303
Author(s):  
Chaerani ◽  
Ahmad Dadang ◽  
Sutrisno ◽  
Bahagiawati ◽  
Muhamad Yunus

Brown planthopper biotype 1, 2, 3 and a representative field population are required for resistance screening of promising rice lines in Indonesia, but the current biotype stocks has shown deviation in virulence patterns. The objectives of this study were to develop a set of brown planthopper populations with differential virulence and to investigate their genetic variability using SSR marker. Females originated from two field populations were selected on variety Mudgo (carries Bph1 gene) or ASD7 (bph2 gene) using honeydew excretion as the virulence parameter. Selection cycles resulted in population T, M, A, and R, which was raised and adapted on variety TN1 (carries no Bph gene), Mudgo, ASD7, and Rathu Heenathi (Bph3, Bph17), respectively. Population R was the most virulent as expected and can be used to represent a field population, but the remaining populations still showed high virulence level. AMOVA and PCoA results based on analysis with 38 SSR primer pairs revealed partial genetic separation among populations, with population R was the most genetically distant from the remaining populations. The desired virulence character of the remaining populations is expected could be achieved after further selection and prolonged adaptation on their respective hosts.


2021 ◽  
Vol 145 ◽  
pp. 105616
Author(s):  
Wei He ◽  
Xincheng Zhao ◽  
Shishuai Ge ◽  
Kongming Wu

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 469
Author(s):  
René Gato ◽  
Zulema Menéndez ◽  
Enrique Prieto ◽  
Rafael Argilés ◽  
Misladys Rodríguez ◽  
...  

Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. As there is no vaccine or specific treatment, the control efforts are directed to the reduction of mosquito populations. The indiscriminate use of insecticides can lead to adverse effects on ecosystems, including human health. The sterile insect technique is a species-specific and environment-friendly method of insect population control based on the release of large numbers of sterile insects, ideally males only. The success of this technique for the sustainable management of agricultural pests has encouraged its evaluation for the population suppression of mosquito vector species. Here, we describe an open field trial to evaluate the effect of the release of irradiated male Ae. aegypti on a wild population. The pilot trial was carried out in a suburb of Havana and compared the mosquito population density before and after the intervention, in both untreated control and release areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant amount of sterility was induced in the field population of the release area, as compared with the untreated control area. The ovitrap index and the mean number of eggs/trap declined dramatically after 12 and 5 weeks of releases, respectively. For the last 3 weeks, no eggs were collected in the treatment area, clearly indicating a significant suppression of the wild target population. We conclude that the sterile males released competed successfully and induced enough sterility to suppress the local Ae. aegypti population.


Author(s):  
René Gato ◽  
Zulema Menéndez ◽  
Enrique Prieto ◽  
Rafael Argilés ◽  
Misladys Rodríguez ◽  
...  

Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. Since there is no vaccine or specific treatment, the control efforts are directed to reduce mosquito populations. The indiscriminate use of pesticides can lead to increase insecticide resistance as well as adverse effects on human health. The sterile insect technique is a species-specific and environmental friendly method of insect control based on the release of large numbers of sterile males. The success of this technique in sustainable control of agricultural pests has encouraged its evaluation for mosquito control. Here, we describe an open field trial to evaluate the effect of the release of irradiated males on a wild population of Aedes aegypti. The case-control study was performed in a suburb of Havana, and compared the mosquito population before and after the intervention, in both control and treated areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant induced sterility was observed in the field population, compared to the control. The ovitrap index and the mean eggs/ trap declined dramatically after an expected lag period of twelve and five weeks, respectively. For the last three weeks, no egg was collected in the treated area, evidencing a significant suppression of the wild population. We conclude that the sterile males released competed successfully, and induced enough sterility to suppress the local Aedes aegypti population.


2021 ◽  
Author(s):  
Taiza Andrade Braga ◽  
Aline Cordeiro Loureiro ◽  
José Bento Pereira Lima ◽  
Ademir J Martins

Abstract Background: Although there is a vast literature concerning insecticide resistance (IR) in Plasmodium vectors from African and Asian continents, similar studies with Neotropical anophelines are scares. Herein we evaluated the IR profile of Anopheles albitarsis s.s. of a laboratory colony and a natural population collected around a rice plantation field. The laboratory colony is original from a collection performed in this same region more than two decades ago. Methods: We collected An. albitarsis females while resting after blood feeding, around rice field plantations in Massaranduba, SC, Brazil. These females laid their eggs in the laboratory, and the larvae were raised in parallel with our lab colony. To be sure about the field samples’ taxonomic status, we amplified and sequenced the mitochondrial COI gene of a sampling of field captured mosquitoes. We performed a simplified knockdown test with larvae exposed to permethrin and deltamethrin and submitted adult females to a WHO like tube test with the pyrethroids permethrin, deltamethrin, and etofenprox, in addition to the organophosphate malathion. A segment of the voltage-gated sodium channel gene (NaV) was amplified and cloned. Based on the observed sequences, we developed a TaqMan genotyping assay for the variation L1014F and calculated the genotypic and allelic frequencies concerning this SNP in the field population.Results: The COI analyses confirmed the taxonomic status of An. albitarsis s.s in laboratory and field samples. The field population was resistant to pyrethroids but not to malathion. We observed the substitutions L1019R, F1020S, and the classical kdr L1014F in the NaV gene. This classical kdr allele was present under low frequencies in the overall field population (2%), although more frequent in pyrethroid-resistant insects.Conclusions: The An. albitarsis s.s. population from Massaranduba was resistant to pyrethroids, likely due to selection pressure exerted by agrochemical pesticides. We registered the classical kdr mutation in a Brazilian Anopheles species for the first time. Further investigations are necessary to disclose additional resistance mechanisms.


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