We evaluated the side-effects of insecticides, herbicides and fungicides on adults of the egg parasitoid Telenomus remus (Nixon) under laboratory conditions. The protocol was adapted from that proposed by the Pesticides and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) for Trichogramma cacoeciae (Marchal). Chlorpyrifos, acephate, beta-cyfluthrin + imidacloprid, spinosad, and pyrethroids were harmful to the parasitoid, whereas methoxyfenozide, diflubenzuron, and flufenoxuron had no effect. Of the herbicides examined, only glyphosate + imazethapyr and 2,4-D amine were classified as harmless on the first and second days of parasitism; paraquat was the most harmful. Other herbicides were harmless on the first day of parasitism, but caused various levels of reduction of T. remus parasitism on the second day. The fungicides were harmless or only slightly harmful.

Pesticide selectivity for the insect egg parasitoid Telenomus remus.

BACKGROUND: The tobacco whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), has developed a high degree of resistance to several chemical classes of insecticides throughout the world. To evaluate the resistance status in West Africa, eight insecticides from different chemical families were tested using the leaf-dip method on four field populations collected from cotton in Benin, Togo and Burkina Faso. RESULTS: Some field populations showed a significant loss of susceptibility to pyrethroids such as deltamethrin [resistance ratio (RR) 3-5] and bifenthrin (RR 4-36), to organophosphates (OPs) such as dimethoate (RR 8-15) and chlorpyrifos (RR 5-7) and to neonicotinoids such as acetamiprid (RR 7-8) and thiamethoxam (RR 3-7). Bemisia tabaci was also resistant to pymetrozine (RR 3-18) and to endosulfan (RR 14-30). CONCLUSION: The resistance of B. tabaci to pyrethroids and OPs is certainly due to their systematic use in cotton treatments for more than 30 years. Acetamiprid has been recently introduced for the control ofwhiteflies.Unfortunately, B. tabaci populations from Burkina Faso seem to be already resistant. Because cross-resistance between these compounds has never been observed elsewhere, resistance to neonicotinoids could be due to the presence of an invasive B. tabaci biotype recently detected in the region. (Resume d'auteur)

Insecticide resistance in field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in West Africa.

Problems with the use of insecticides has brought losses, such as, negative impact on natural enemies. When these beneficial insects reduce cause the eruption of pests and resurgence it’s more common. Thus principles of conservation these arthropods are extremely important in the biological natural control of pests, so that these enemies may present a high performance. Because of the negative impacts caused by insecticides on agriculture and their harmful effects on natural enemies, the objective of this article is to approach two important subjects, divided into three parts. Part I relates to the description of the main crop pests and their natural enemies; Part II involves the impact of insecticides on predators and parasitoids and Part III focuses on the selectivity of several groups of insecticides to natural enemies. Before spraying insecticides, it is necessary to choose a product that is efficient to pests and selective to natural enemies. So, it is indispensable to identify correctly the groups and species of natural enemies, since insecticides have an impact on their survival, growth, development, reproduction (sexual ratio, fecundity, longevity and fertility), and behavior (motility, orientation, feeding, oviposition and learning) of insects. The mechanisms of toxicity and selectivity of insecticides are related to the properties of higher or lower solubility and molecular weight. Besides, characteristics of the cuticular composition of the integument of natural enemies are extremely important in the selectivity of a product or the tolerance of a certain predator or parasitoid to this molecules. Impacto e Seletividade de Inseticidas para Predadores e Parasitoides Resumo. Dentre os problemas advindos do uso de inseticidas, a destruicao de inimigos naturais e fator importante. Estes insetos beneficos podem reduzir problemas de erupcao de pragas secundarias, ressurgencia de pragas e manter a praga abaixo do nivel de dano economico. Dessa forma a conservacao de inimigos naturais, para que os mesmos exercam alta performance frente as pragas, e de extrema importância em controle biologico de pragas. Metodo de controle essencial utilizados nos programas de manejo integrado de pragas. Tendo em vista os impactos negativos dos inseticidas na agricultura e os seus efeitos adversos sobre os inimigos naturais, este artigo visa abordar dois assuntos importantes, que para isso e dividido em tres partes. A parte I relacionada com o reconhecimento das principais pragas agricolas e seus inimigos naturais; a parte II envolve o impacto dos inseticidas sobre os predadores e parasitoides e a parte III abordara sobre a seletividade dos diversos grupos de inseticidas aos inimigos naturais. Antes de se pulverizar inseticida e necessario a escolha de um produto que seja seletivo e eficiente, assim torna-se imprescindivel identificar de forma correta os grupos e especies de inimigos naturais. Uma vez que os inseticidas apresentam impacto sobre a sobrevivencia, o crescimento e desenvolvimento, na reproducao (razao sexual, fecundidade, longevidade e fertilidade), no comportamento (mobilidade, orientacao, alimentacao, oviposicao e aprendizado). Os mecanismos de toxicidade e seletividade dos inseticidas estao relacionados as propriedades de maior ou menor solubilidade e peso molecular. Alem disso, caracteristicas da composicao cuticular do integumento dos inimigos naturais sao de extrema importância na seletividade de um produto ou a tolerância de determinado predador ou parasitoide.

https://dialnet.unirioja.es/descarga/articulo/3695220.pdf

Impact and Selectivity of Insecticides to Predators and Parasitoids

Sustainable methods to control insect pests that affect crop yield have become a great challenge to mainly smallholder farmers. Beneficial insects in agricultural fields play an important role in natural pest control and pollination. The use of synthetic and botanical pesticides has detrimental effects to both natural enemies and pollinators in agricultural fields. The pesticides affect the survival of a range of life cycle stages, reductions in reproductive capacity, changes in the suitability of hosts for parasitising or predation, reduced emergence of parasitoids from sprayed host eggs and cause direct mortality. This has caused a serious menace to biological control agents and pollinators. When natural enemies are reduced, even more serious consequences may result for pest population dynamics which include the phenomena of resurgence and eruption of secondary pests. The decrease in pollinators reduces agricultural productivity. This review aims at exploring the side effects of synthetic and botanical pesticides on beneficial insects to give the basis for research on the negative impacts of synthetic and botanical pesticides on these insects. This information will assist in optimizing the use of pesticides in integrated pest management programmes by employing more sustainable and ecosystem benign practices such as the use of right dosage and selective pesticides in agricultural fields.

/pdf/impacts-of-synthetic-and-botanical-pesticides-on-beneficial-2d0l62dgja.pdf

Impacts of Synthetic and Botanical Pesticides on Beneficial Insects

Lethal and sublethal effects of seven insecticides on three beneficial insects in laboratory assays and field trials.

Efficient chemical control is achieved when insecticides are active against insect pests and safe to natural enemies. In this study, the toxicity of 17 insecticides to the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the selectivity of seven insecticides to natural enemies of this insect pest were evaluated. To determine the insecticide toxicity, B. tabaci adults were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion, methamidophos, bifenthrin, cypermethrin, deltamethrin, esfenvalerate, fenitrothion, fenpropathrin, fenthion, phenthoate, permethrin and trichlorphon at 50 and 100% of the field rate (FR), and to water (untreated control). To determine the insecticide selectivity, adults of Encarsia sp., Acanthinus sp., Discodon sp. and Lasiochilus sp. were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion and methamidophos at 50 and 100% FR, and to water. Groups of each insect species were exposed to kale leaves preimmersed in each treatment under laboratory conditions. Mortality of exposed individuals was recorded 24 h after treatment. Cartap and imidacloprid at 50 and 100% FR and abamectin and acetamiprid at 100% FR showed insecticidal activity to B. tabaci adults. Abamectin at 50 and 100% FR was the least insecticidal compound to the natural enemies Acanthinus sp., Discodon sp. and Lasiochilus sp. The present results suggest that abamectin at 100% FR may decrease B. tabaci field populations but can still be harmless to predators. Implications of these results within an integrated pest management context are discussed.

Toxicity of insecticides to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies.

The selectivity of abamectin, acephate, carbaryl, deltamethrin, fenitrothion, fenpropathrin, methyl parathion and trichlorfon to the predators Brachygastra lecheguana (Latreille), Protonectarina sylveirae (Saussure) and Protopolybia exigua (Saussure) (Hymenoptera: Vespidae) was evaluated using insecticide concentrations corresponding to 50% and 100% of the current recommended rate for citrus caterpillars. The insecticides studied were not selective in favor of the predator P. sylveirae. Fenitrothion, fenpropathrin, methyl parathion and trichlorfon were not selective in favor of the predator B. lecheguana and P. exigua. Abamectin, acephate and carbaryl showed median selectivity in favor of P. exigua, and the same was observed with abamectin and carbaryl in favor of B. lecheguana. Acephate was selective in favor of B. lecheguana and deltamethrin in favor of P. exigua. The high mortalities caused by deltamethrin in P. sylveirae, trichlorfon in B. lecheguana and acephate in P. exigua decreased when the lower concentration was used. B. lecheguana was the most tolerant predator to the higher acephate concentration, followed by P. exigua and P. sylveirae. P. exigua was more tolerant to the higher deltamethrin concentration than B. lecheguana and P. sylveirae. The three predator species were highly susceptible to both concentrations of fenitrothion, fenpropathrin and methyl parathion, and the higher concentration of trichlorfon.

/pdf/seletividade-de-oito-inseticidas-a-predadores-de-lagartas-em-48mzxzg8uo.pdf

Seletividade de oito inseticidas a predadores de lagartas em citros

Estudou-se a seletividade dos inseticidas acefato, deltametrina, dimetoato, metamidofos, paratiom metilico e pirimicarbe a ninfas de ultimo estadio de Myzus persicae (Sulzer) (Homoptera: Aphididae), em relacao a adultos, ninfas de primeiro, segundo e terceiro estadios de Doru luteipes (Scudder) (Dermaptera: Forficulidae). Pirimicarbe foi altamente seletivo em favor de todos os estadios do predador, sendo que os demais inseticidas foram medianamente seletivos em favor de adultos do predador. Deltametrina, paratiom metilico e dimetoato foram medianamente seletivos em favor de ninfas de terceiro estadio de D. luteipes, sendo que o mesmo ocorreu com os dois primeiros destes em relacao a ninfas de primeiro e segundo estadios, respectivamente. Acefato foi pouco seletivo em favor de ninfas de segundo e terceiro estadios, sendo que o mesmo ocorreu com paratiom metilico, deltametrina e metamidofos em relacao a ninfas de primeiro, segundo e terceiro estadios, respectivamente. Dimetoato e metamidofos foram mais toxicos a ninfas de primeiro e segundo estadios do predador do que ao pulgao, sendo que o mesmo ocorreu com o acefato para ninfas de primeiro estadio. Adultos e ninfas de segundo e terceiro estadios de D. luteipes foram mais tolerantes ao acefato, paratiom metilico e pirimicarbe do que ninfas de primeiro estadio do predador. Ninfas de primeiro e segundo estadios apresentaram tolerância semelhante a deltametrina, dimetoato e metamidofos. As curvas de concentracao-mortalidade de deltametrina, metamidofos e pirimicarbe (para todos os estadios de desenvolvimento de D. luteipes), dimetoato (para adultos e ninfas de primeiro e segundo estadios), paratiom metilico (para ninfas de primeiro e terceiro estadio) e acefato (para adultos), apresentaram maiores inclinacoes do que as curvas destes inseticidas para M. persicae.

/pdf/inseticidas-seletivos-a-tesourinha-doru-luteipes-scudder-2tb5puanqi.pdf

Inseticidas seletivos à tesourinha Doru luteipes (Scudder) utilizados no controle do pulgão verde em brássicas

Distribution of Aculops Lycopersici on Lycopersicon esculentum and Lycopersicon hirsutum dossels and leaves

This work was carried out to evaluate the insecticide effect of hexanic extracts of the plants: Tropaeolium majus, Helianthus annuus, Artemisia vulgaris and Sesamum indicum to the coffee leafminer Leucoptera coffeellum (Guérin-Mèneville) (Lepidoptera: Lyonetiidae). The experiment was driven in the Laboratory of Integrated Pest management from the UFV, from the may to June, 1998. The vegetable material was placed in beckers adding hexane as the solvent. After four hours, the foliate remains were taken away and the extract was concentrated on rotative evaporator. The statistic design was completely randomized with four repetitions. Each experimental parcel was constituted of Petri dishes with 10 caterpillars of the L. coffeellum. Besides the control, treatments were constituted of the extracts. Six, 12 and 24 hours later, the mortality of the insects was evaluated. It was observed that the hexanic extracts from T. majus showed insecticide effect (100,00% of mortality). The hexanic extracts from H. annuus, A. vulgaris and S. indicum didn't show insecticide effect.

Tederson Luiz Galvan

Papers

Toxicity of insecticides to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies.

Seletividade de oito inseticidas a predadores de lagartas em citros

Inseticidas seletivos à tesourinha Doru luteipes (Scudder) utilizados no controle do pulgão verde em brássicas

Distribution of Aculops Lycopersici on Lycopersicon esculentum and Lycopersicon hirsutum dossels and leaves

Efeito inseticida de quatro plantas ao bicho-mineiro do cafeeiro Leucoptera coffeellum