Current Strategies and Future Outlook for Managing the Neotropical Tomato Pest Tuta absoluta (Meyrick) in the Mediterranean Basin.

The invasion of new regions by exotic pests has been more than ever a critical issue that warrants coordinated international actions to manage established populations and prevent further spreading. Invasive insects can undermine the ecological equilibrium of both natural and agricultural ecosystems. Moreover, increasing temperatures due to climatic change exacerbate this problem by allowing pests to further reach regions previously considered unsuitable. The tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera) is an exotic pest native to Peru that has spread beyond Neotropical America. In Europe, its occurrence was reported in Spain in 2006, and thereafter, it has spread throughout the Mediterranean Basin and further into Africa and part of Asia. While T. absoluta can cause losses to tomato production all over the globe, the differences in each invaded region (e.g., climate, vegetation) may affect its population dynamics and, consequently, management protocols. Therefore, the main intent of this forum paper is to explore how European growers and researchers are dealing with T. absoluta in the Mediterranean area. As for many other invasive pests, the best approach has been the adoption of integrated pest management (IPM). Specifically, the integration of biological control agents (e.g., mirid predators and egg parasitoids), microbial insecticides (i.e., Bacillus thuringiensis), selective chemical insecticides, and sex pheromone-based control has proven adequate, especially in tomato greenhouses. Nonetheless, some of the challenges ahead include the development of resistant tomato cultivars, the management of wild vegetation and companion plants to optimize the conservation of natural enemies and their effectiveness at the crop level, the management of insecticide resistance, and the improvement of sex pheromone-based tactics.

Physiological selectivity and activity reduction of insecticides by rainfall to predatory wasps of Tuta absoluta.

In this study, we carried out three bioassays with nine used insecticides in tomato crops to identify their efficiency against tomato leaf miner Tuta absoluta, the physiological selectivity and the activity reduction of insecticides by three rain regimes to predatory wasps Protonectarina sylveirae and Polybia scutellaris. We assessed the mortality caused by the recommended doses of abamectin, beta-cyfluthrin, cartap, chlorfenapyr, etofenprox, methamidophos, permethrin, phenthoate and spinosad to T. absoluta and wasps at the moment of application. In addition, we evaluated the wasp mortality due to the insecticides for 30 days on plants that did not receive rain and on plants that received 4 or 125 mm of rain. Spinosad, cartap, chlorfenapyr, phenthoate, abamectin and methamidophos caused mortality higher than 90% to T. absoluta, whereas the pyrethroids beta-cyfluthrin, etofenprox and permethrin caused mortality between 8.5% and 46.25%. At the moment of application, all the insecticides were highly toxic to the wasps, causing mortality higher than 80%. In the absence of rain, all the insecticides continued to cause high mortality to the wasps for 30 days after the application. The toxicity of spinosad and methamidophos on both wasp species; beta-cyfluthrin on P. sylveirae and chlorfenapyr and abamectin on P. scutellaris, decreased when the plants received 4 mm of rain. In contrast, the other insecticides only showed reduced toxicity on the wasps when the plants received 125 mm of rain.

Efeito de genótipos de tomateiro e de extratos aquosos de folhas de Melia azedarach e de sementes de Azadirachta indica sobre Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) / Effects of tomato genotypes and aqueous extracts of Melia azedarach leaves and Azadirachta indica seeds on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

Insecticide plants are an important tool among the new alternatives for pest control in IPM systems because they reduce the use of synthetic insecticides, preserving human health and the environment. We investigated the effects of aqueous extracts of Melia azedarach leaves and Azadirachta indica seeds and three tomato genotypes, 'Santa Clara', 'IPA-5' - Solanum lycopersicum (= Lycopersicon esculentum Mill), and LA444-1 - S. peruvianum (= L. peruvianum), on the development, reproduction and longevity of the tomato pinworm Tuta absoluta (Meyrick), under laboratory conditions. The trials were set up in a completely randomized design, with nine treatments [three genotypes x two extracts (M. azedarach and A. indica) and control]. The replication consisted on five tubes, each with three newly hatched larvae, totalizing 90 individuals per treatment. The larvae were fed with tomato leaves treated with aqueous extracts at 0.1 percent concentration or distilled water (control) and daily observed until adults' emergence. Larval and pupal development and mortality, pupal weight, longevity and fecundity were evaluated. The accession LA444-1 negatively affected the development and reproduction of T. absoluta; the tomato pinworm had similar development and reproduction on 'IPA-5' and 'Santa Clara' (the susceptible control). The association of resistant tomato genotypes and extracts of M. azedarach leaves and neem seeds did not result in synergistic or antagonistic effects on T. absoluta.

Número de ínstares larvais de Tuta absoluta (Meyrick) em genótipos de tomateiro

The South American tomato pinworm, Tuta absoluta (Meyrick), is one of the most important tomato pests in Brazil and it has been controlled mainly by insecticides, which may be undesirable because of economical and environmental concerns. These problems can be minimized with alternative control tactics, such as the use of the resistant varieties. However, there is a lack of studies on alternative tactics to control T. absoluta. To obtain information on the insect-plant interactions, the number of instars of T. absoluta on two tomato genotypes: Lycopersicon hirsutum f. glabratum (PI 134417 - resistant) and L. esculentum (`Santa Clara' - susceptible) were determined. The experiment was carried out in climatic chambers, using two temperatures the 26 ± 0,5 and 30 ± 0,5ºC. Neonate larvae were fed with leaves of each genotype. Fifteen larvae of each treatment were removed daily to measure the width of the cephalic capsule. The development of the insect followed the Dyar's rule and four larval instars were found in all treatments.

A traça Tuta absoluta (Meyrick) é uma das principais pragas do tomateiro no Brasil e tem sido controlada quase que exclusivamente com inseticidas, o que é indesejável tanto por motivos econômicos quanto ambientais. Esses problemas podem ser minimizados com métodos alternativos de controle, tal como a resistência varietal que é uma alternativa interessante, mas que ainda precisa ser mais estudada. Visando obter mais informações sobre a relação inseto-planta, estudou-se o número de instares da traça em dois genótipos de tomateiro Lycopersicon hirsutum f. glabratum (PI 134417 -- resistente) e L. esculentum (`Santa Clara' - suscetível). O experimento foi desenvolvido em câmara climatizada em duas temperaturas (26 ± 0,5 e 30 ± 0,5ºC). As lagartas recém-eclodidas foram alimentadas com folhas dos dois genótipos. Diariamente foram retiradas 15 lagartas de cada tratamento para medições da largura da cápsula cefálica. O desenvolvimento do inseto seguiu a regra de Dyar e, em qualquer das situações testadas, apresentou quatro ínstares larvais.

Número de ínstares larvais de Tuta absoluta (Meyrick) em genótipos de tomateiro

The South American tomato pinworm, Tuta absoluta (Meyrick), is one of the most important tomato pests in Brazil and it has been controlled mainly by insecticides, which may be undesirable because of economical and environmental concerns. These problems can be minimized with alternative control tactics, such as the use of the resistant varieties. However, there is a lack of studies on alternative tactics to control T. absoluta. To obtain information on the insect-plant interactions, the number of instars of T. absoluta on two tomato genotypes: Lycopersicon hirsutum f. glabratum (PI 134417 - resistant) and L. esculentum (`Santa Clara' - susceptible) were determined. The experiment was carried out in climatic chambers, using two temperatures the 26 ± 0,5 and 30 ± 0,5ºC. Neonate larvae were fed with leaves of each genotype. Fifteen larvae of each treatment were removed daily to measure the width of the cephalic capsule. The development of the insect followed the Dyar's rule and four larval instars were found in all treatments.

A traça Tuta absoluta (Meyrick) é uma das principais pragas do tomateiro no Brasil e tem sido controlada quase que exclusivamente com inseticidas, o que é indesejável tanto por motivos econômicos quanto ambientais. Esses problemas podem ser minimizados com métodos alternativos de controle, tal como a resistência varietal que é uma alternativa interessante, mas que ainda precisa ser mais estudada. Visando obter mais informações sobre a relação inseto-planta, estudou-se o número de instares da traça em dois genótipos de tomateiro Lycopersicon hirsutum f. glabratum (PI 134417 -- resistente) e L. esculentum (`Santa Clara' - suscetível). O experimento foi desenvolvido em câmara climatizada em duas temperaturas (26 ± 0,5 e 30 ± 0,5ºC). As lagartas recém-eclodidas foram alimentadas com folhas dos dois genótipos. Diariamente foram retiradas 15 lagartas de cada tratamento para medições da largura da cápsula cefálica. O desenvolvimento do inseto seguiu a regra de Dyar e, em qualquer das situações testadas, apresentou quatro ínstares larvais.

Bioatividade de Extratos Aquosos de Melia azedarach L. Sobre o Desenvolvimento de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) em Tomateiro / Bioactivity of Aqueous Extracts of Melia azedarach L. on Tomato Pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

The effect of aqueous extracts of Melia azedarach L. on the development of the tomato pinworm Tuta absoluta (Meyrick) was investigated under laboratory conditions. After hatching, the larvae were fed on tomato leaves (Lycopersicon esculentum, cv. Santa Clara) treated with chinaberry's extracts. The larval and pupal development and mortality and pupal weight were evaluated. Firstly, the trials were carried out with three different concentrations of leaf extracts (0.1, 1.0 e 5.0 percent), in order to determine the most appropriate one for bioactivity studies. Later, the aqueous extracts of different parts of M. azedarach were compared using the selected concentration (0.1 percent). The leaf extract was the most effective for tomato pinworm bioactivity studies, followed by raw fruits, branches and ripe fruits.

Determinou-se, em condições de laboratório, o efeito de extratos aquosos de Melia azedarach L. sobre o desenvolvimento da traça-do-tomateiro Tuta absoluta (Meyrick). Para isso, as lagartas foram alimentadas, desde a eclosão, com folhas de tomateiro (Lycopersicon esculentum, cv. Santa Clara), tratadas com extratos dessa meliácea, avaliando-se a duração e viabilidade das fases larval e pupal e o peso de pupas. Inicialmente, foram testadas três concentrações (0,1; 1 e 5 por cento) do extrato de folhas, visando determinar a concentração adequada para estudos de bioatividade dessa planta. Posteriormente, utilizando-se a concentração selecionada (0,1 por cento), foi comparada a bioatividade dos extratos de diferentes estruturas de M. azedarach, constatando-se que as folhas foram a estrutura vegetal com maior bioatividade sobre a traça, vindo a seguir os frutos verdes, ramos e frutos maduros.

Efeito Associado de Genótipo de Tomateiro Resistente e Bacillus thuringiensis var. kurstaki Sobre o Desenvolvimento de Tuta absoluta Meyrick (Lep. Gelechiidae) / Associated Effect Between Tomato Resistant Genotype and Bacillus thuringiensis var. kurstaki on the Development of Tuta absoluta Meyrick (Lep. Gelechiidae)

The objective of this study was to survey the possible alterations on the development of Tuta absoluta (Meyrick) larvae fed on leaves of Lycopersicon hirsutum f. glabratum, PI 134417 - resistant to this insect and L. esculentum, 'Santa Clara' - susceptible, treated with formulation of Bacillus thuringiensis var. kurstaki (Btk). In order to obtain larvae in the different instars used in these experiments, neonate larvae were reared on the tested Lycopersicon plants until the desired instar. For each larval ages (unfed neonate, 1st, 2nd, 3rd, and 4th instars), were made a separate bioassays in which larvae fed on tomato leaves of the two genotypes + Btk. Larval developmental time was delayed and larval survival was reduced by both resistant tomato and Btk treatment. There was a significant interaction between these treatments for larval development time when 3rd instar larvae fed on Btk-treated leaves and for larval survival, when 4th instar larvae fed on Btk-treated leaves. The pupal weight was affected more drastically by the genotype that for the pathogen. The application of Btk on tomato genotypes insect resistant/susceptible increased the efficiency of the control of T. absoluta wich depended on the age of larvae and was larger in the first two instares.

O objetivo do trabalho foi avaliar as possíveis alterações no desenvolvimento de Tuta absoluta (Meyrick) alimentada com folhas de Lycopersicon hirsutum f. glabratum, PI 134417 - resistente ao inseto e L. esculentum, 'Santa Clara' - suscetível, tratadas com formulação de Bacillus thuringiensis var. kurstaki (Btk). Para se obter insetos nos diferentes ínstares testados, lagartas recém-eclodidas foram criadas nas plantas de Lycopersicon testadas até o ínstar desejado. Para cada uma das idades larvais (lagartas recém-eclodidas (não alimentadas), 1°, 2°, 3° e 4° ínstares) foram realizados experimentos nos quais as lagartas foram alimentadas com folhas dos dois genótipos + Btk. A duração da fase larval foi alongada e a sobrevivência reduzida, tanto pelo genótipo resistente como pelo patógeno. Ocorreu interação entre os tratamentos para duração, quando lagartas no 3° ínstar foram alimentadas com folhas tratadas com Btk e para a sobrevivência, quando lagartas no 4° ínstar se alimentaram com folhas tratadas. O peso de pupas foi afetado mais drasticamente pelo genótipo que pelo entomopatógeno. A aplicação de Btk em genótipos de tomateiro resistentes/suscetíveis aumentou a eficiência de controle de T. absoluta, que foi dependente da idade das lagartas e maior nos dois primeiros ínstares.

Extratos aquosos de Trichilia pallida e a traça-do-tomateiro

The effect of aqueous extracts of Trichilia pallida leaves and twigs on the development and oviposition of Tuta absoluta was evaluated. Larvae of T. absoluta were fed with tomato leaves (Lycopersicon esculentum, cv. Santa Clara) previously treated with extracts at concentrations of 0.1; 1.0 and 5.0%. The effects of the leaf extracts at 1.0 and 5.0% were evaluated on eggs of this pest. Free-choice non-preference tests for oviposition were also conducted with treated and non-treated tomato leaves with the extract at concentration of 5.0%. Leaf and twig extracts affect the insect development mainly at the larval stage, increasing the length and reducing viability of this stage. The activity of the leaf extract is greater than that of the twig extract with the reduction of larval viability to approximately 20% at concentration of 1.0%. No ovicidal activity was detected with T. pallida leaf extract at 5.0%, however, the treated substract can become less attractive for oviposition.

Avaliou-se o efeito de extratos aquosos de folhas e de ramos da planta inseticida Trichilia pallida sobre o desenvolvimento e oviposição da traça-do-tomateiro, Tuta absoluta. Acompanhou-se o desenvolvimento do inseto em folhas de tomateiro (Lycopersicon esculentum, cv. Santa Clara) previamente submersas nos extratos nas concentrações de 0,1; 1,0 e 5,0%. Também foi avaliado o efeito dos extratos de folhas a 1,0 e 5,0%, pulverizados sobre ovos do inseto, e a não-preferência para oviposição, com chance de escolha, em folhas de tomateiro com e sem esse extrato a 5%. Verificou-se que os extratos de folhas e de ramos prejudicam o desenvolvimento do inseto afetando principalmente a fase larval, aumentando a duração e reduzindo a viabilidade deste período. O extrato de folhas apresenta maior atividade que o de ramos, reduzindo a viabilidade larval a valores próximos a 20%, já na concentração de 1%. O extrato de folhas a 5% não apresenta efeito ovicida mas, o substrato tratado pode tornar-se menos preferido para oviposição.

Extratos aquosos de Trichilia pallida e a traça-do-tomateiro

The effect of aqueous extracts of Trichilia pallida leaves and twigs on the development and oviposition of Tuta absoluta was evaluated. Larvae of T. absoluta were fed with tomato leaves (Lycopersicon esculentum, cv. Santa Clara) previously treated with extracts at concentrations of 0.1; 1.0 and 5.0%. The effects of the leaf extracts at 1.0 and 5.0% were evaluated on eggs of this pest. Free-choice non-preference tests for oviposition were also conducted with treated and non-treated tomato leaves with the extract at concentration of 5.0%. Leaf and twig extracts affect the insect development mainly at the larval stage, increasing the length and reducing viability of this stage. The activity of the leaf extract is greater than that of the twig extract with the reduction of larval viability to approximately 20% at concentration of 1.0%. No ovicidal activity was detected with T. pallida leaf extract at 5.0%, however, the treated substract can become less attractive for oviposition.

Avaliou-se o efeito de extratos aquosos de folhas e de ramos da planta inseticida Trichilia pallida sobre o desenvolvimento e oviposição da traça-do-tomateiro, Tuta absoluta. Acompanhou-se o desenvolvimento do inseto em folhas de tomateiro (Lycopersicon esculentum, cv. Santa Clara) previamente submersas nos extratos nas concentrações de 0,1; 1,0 e 5,0%. Também foi avaliado o efeito dos extratos de folhas a 1,0 e 5,0%, pulverizados sobre ovos do inseto, e a não-preferência para oviposição, com chance de escolha, em folhas de tomateiro com e sem esse extrato a 5%. Verificou-se que os extratos de folhas e de ramos prejudicam o desenvolvimento do inseto afetando principalmente a fase larval, aumentando a duração e reduzindo a viabilidade deste período. O extrato de folhas apresenta maior atividade que o de ramos, reduzindo a viabilidade larval a valores próximos a 20%, já na concentração de 1%. O extrato de folhas a 5% não apresenta efeito ovicida mas, o substrato tratado pode tornar-se menos preferido para oviposição.