ABSTRACT Plant resistance is an important tactic within the precepts of Integrated Pest Management, and the existence of grain sorghum hybrids with multiple insect resistance could benefit crop management and sustainability. This study evaluated the susceptibility of 30 grain-sorghum hybrids to three major pests, namely, fall armyworm (FAW) Spodoptera frugiperda, sugarcane borer (SCB) Diatraea saccharalis, and green-belly stink bug (GBS) Diceraeus melacanthus. The hybrids were cultivated and experiments with each insect species were conducted separately in a greenhouse. For FAW, visual injury assessments were performed on plants 7 and 14 days after infestation (DAI). For SCB, insect presence and injury were assessed 40 DAI. For GBS, the plants were evaluated using a damage rating scale 12, 19, and 26 DAI. Cluster analysis allowed separating the grain sorghum hybrids into groups regarding the levels of resistance to each pest. Hybrid BRS373 stood out as moderately resistant to FAW; AG1090, 80G20, BRAVO, BRS373, AG1615, and IG220 were the most promising for SCB; and for GBS, hybrids 50A40, A9735R, JADE, ENFORCER, BUSTER, 50A10, and IG244 were the most nominated. This information will significantly aid sorghum breeding programs focused on developing commercial hybrids that comprise both insect-resistance and high-yield characteristics. However, further research should evaluate potential chemical and morphological plant traits underlying the lower levels of susceptibility to FAW, SCB, and GBS found in the selected sorghum hybrids.

ABSTRACT: Whitefly Bemisia tabaci (Gennadius) biotype B is the major pest of common bean (Phaseolus vulgaris L.) in Brazil and other countries. Host plant resistance is one of the cornerstones of Integrated Pest Management (IPM), and assessment of cultivars for insect resistance is fundamental to provide farmers options for pest control. This study evaluated common bean resistance to whitefly in the winter and rainy seasons in Jaboticabal, Brazil, and correlated the infestation with climatic factors. The plant part and development period of common bean that are more susceptible to whitefly infestation were also examined for potential use in IPM. Field experiments were carried out using 18 and 19 commercial cultivars in the winter and rainy seasons, respectively. Whitefly eggs, nymphs, and adults in the upper part and lower part of plants were sampled from 25 to 60 days after emergence (DAE). Cultivars IAC-Una and IAC-Eldorado had less oviposition and the former also showed lower adult infestation in the winter season. In the rainy season, cultivars IAPAR-81 and Guará had a smaller number of eggs, whereas IAC-Centauro was less infested by nymphs. The number of nymphs and adults was similar among cultivars in the winter and rainy seasons, respectively. The upper part of plants had a greater number of eggs and adults, while, the lower part harbored larger numbers of nymphs. Common bean was more susceptible to whitefly at 25-32 DAE in both seasons. These results add useful information to IPM of whitefly in common bean.

Tuta absoluta é praga chave do tomateiro, causando danos consideráveis à produção. O controle tem sido feito principalmente com inseticidas sintéticos, porém óleos de origem botânica têm-se destacado no controle de artrópodes. Este trabalho teve por objetivo avaliar os efeitos do óleo de Melia azedarach sobre T. absoluta, também conhecido por óleo de cinamomo. O óleo extraído de M. azedarach foi diluído em 50,0 mL de água destilada nas concentrações de 1,87; 3,75; 7,50; 15,00; 30,00 e 60,00 mg mL-1, constituindo-se os respetivos tratamentos, além do inseticida Deltametrina 25 EC (2,5% de deltametrina na formulação emulsionável) com concentração de 30 ml para 100 L de água (0,3%) e testemunha (água). Foram realizados testes de preferência alimentar com e sem chance de escolha, onde foi avaliada a atratividade para lagartas em diferentes dias após aplicação dos tratamentos (D.A.A.) e a área foliar consumida. Também se conduziu outro ensaio onde se avaliaram os seguintes parâmetros: número de lagartas mortas a 2, 5, 7 e 10 D.A.A. e duração do período e mortalidade larval e pupal. O óleo de M. azedarach não causou efeito de repelência e deterrência alimentar em T. absoluta, porém foi efetivo na mortalidade de lagartas de T. absoluta.

Tuta absoluta is a key pest of tomato, causing considerable damage. Control has been conducted mainly using synthetic insecticides. However, oils of botanical origin are promising for the control of arthropods. The objective of this work was to evaluate the effects on T. absoluta of the Melia azedarach oil, also known as cinnamon oil. The oil extracted from M. azedarach was diluted in 50,0 mL of distilled water at the concentrations 1,87; 3,75; 7,50; 15,00; 30,00 and 60,00 mg mL-1 in addition to the insecticide deltametrin 25 EC (2,5% deltamethrin in the emulsifiable concentrate) with a concentration of 30 mL per 100 L of water (0,3%) and control (water). Food preference tests were carried out with and without a choice, where the attractiveness to caterpillars was evaluated on different days after application of the treatments (D.A.A.), along with the leaf area consumed. Another trial was conducted to evaluate the following parameters: number of dead caterpillars at 2, 5, 7 and 10 D.A.A. and duration of the period and larval and pupal mortality. M. azedarach oil did not cause repellency or food deterrence in T. absoluta, but was effective on mortality of T. absoluta caterpillars.

Resumen Las larvas de Diabrotica speciosa (Germar) son una de las principales plagas subterráneas de varios cultivos y su principal hospedero es el maíz (Zea mays). Este estudio tuvo como objetivo evaluar los efectos de extracto de nim formulado en aceite y extracto de nim en micro encapsulación para el control de larvas de D. speciosa, así como el efecto de la aplicación de las distintas formulaciones en el desarrollo de las plantas de maíz. En el primer experimento, las dosis 0,25; 0,5; 1,0; 2,0; y 4,0 mL de extracto de nim formulado en aceite fueron aplicadas por 25 g de suelo y comparadas con el insecticida fipronil WG y agua desionizada (control). En el segundo experimento, las dosis 160, 80, 40, 20 y 10 mg de extracto de nim en formulación micro encapsulada fueron aplicadas por 25 g de suelo, y comparadas con los controles. Ambas formulaciones de nim fueron tan eficientes como el insecticida fipronil WG en el control de larvas de D. speciosa. Las dosis evaluadas de las formulaciones de nim no interfieren negativamente en el desarrollo de las plantas de maíz. Se concluye que, a partir de los resultados de esta investigación y bajo condiciones de laboratorio, las formulaciones extracto de nim formulado en aceite y extracto de nim en micro encapsulación son promisoras para el control de larvas de D. speciosa en maíz, beneficiando el manejo sustentable de plagas.

Abstract Diabrotica speciosa larvae have been considered to be one of the major subterranean pests of several crops, and its most susceptible host is maize (Zea mays). This study aimed to evaluate the effects of oil-formulated neem extract and lignin-microencapsulated neem extract for D. speciosa larvae control. Effects of applications of neem formulations on the growth of maize plants were also assessed. In the first assay, 0.25, 0.5, 1.0, 2.0, and 4.0 mL of oil-formulated neem extract were applied per 25 g soil and were compared with the insecticide fipronil WG and deionized water. In the second assay, lignin-microencapsulated neem extract was applied at 160, 80, 40, 20 and 10 mg per 25 g soil, and compared with the same controls. Both neem formulations were as efficient as the insecticide fipronil WG in the control of D. speciosa larvae. The evaluated doses of neem formulations did not interfere on maize plants growth. Results of this study permit concluded that, under laboratory conditions, oil-formulated neem extract and lignin-microencapsulated neem extract formulations are promising for controlling D. speciosa larvae in maize, and might benefit sustainable pest management.

The southern armyworm Spodoptera eridania is a polyphagous species that can feed on cowpea plants. Although there is some knowledge about the resistance of cowpea cultivars, little is known on the effects of neem oil to control pest insects of cowpea in Brazil. This study aimed to evaluate the effects of cowpea cultivars combined with neem oil on attractiveness, feeding, and development of Spodoptera eridania (Cramer). The experiment was carried out under environmentally controlled conditions, and set up in a 6 x 3 factorial arrangement using six cowpea cultivars and two doses of neem oil plus the control (deionized water). Free-choice and no-choice feeding preference assays were performed to assess treatment attractiveness to the larvae and leaf consumption. Duration and survival of larvae, pre-pupae, and pupae, weights of larvae and pupae, longevity of adults, sex ratio, duration of larva-to-adult period, and larval mortality after 3, 6, 12, and 24 days were recorded. Cultivars BRS Urubuquara and BR17 Gurgueia were the least consumed in the free-choice test. Neem oil at 0.35 and 0.7% reduced leaf consumption. Cultivars BRS Novaera and BR17 Gurgueia showed to be the least suitable for S. eridania development. Neem oil at both doses affected S. eridania development. Cultivars BR7 Gurgueia and BRS Novaera were moderately resistant; BR3 Tracuateua, susceptible; and Sempre Verde, Milênio, and BRS Urubuquara were highly susceptible to S. eridania.

Spodoptera eridania es una especie polífaga, cuya oruga puede alimentarse de plantas de caupí. Aunque hay algunos conocimientos sobre la resistencia de cultivares de caupí, se conoce poco sobre los efectos de aceite de nim para controlar insectos plaga de caupí, en Brasil. Esta investigación tuvo como objetivo evaluar los efectos de cultivares de caupí asociados con aceite de nim sobre la atracción, alimentación, y desarrollo de Spodoptera eridania (Cramer). El experimento se llevó a cabo bajo condiciones ambientales controladas, en un diseño factorial 6x3, evaluando seis cultivares de caupí y dos dosis de aceite de nim, además del tratamiento testigo (agua desionizada). Se realizaron pruebas de no preferencia para alimentación con y sin opción de escoger para evaluar la atracción de los tratamientos a las larvas y el consumo de las hojas. Se registró la duración y supervivencia de larvas, prepupas y pupas, pesos de larvas y pupas, longevidad de los adultos, proporción sexual, duración del período de larva a adulto, y mortalidad larval después de 3, 6, 12, y 24 días. Los cultivares BRS Urubuquara y BR17 Gurgueia fueron los menos consumidos en la prueba de libre elección. El consumo de hojas fue reducido cuando utilizó aceite de nim a 0,35 y 0,7%. Los cultivares BRS Novaera y BR17 Gurgueia mostraron ser los menos adecuados para el desarrollo de S. eridania. Aceite de nim en ambas dosis afectó el desarrollo de S. eridania. Los cultivares BR7 Gurgueia y BRS Novaera fueron moderadamente resistentes; BR3 Tracuateua, susceptible; y Sempre Verde, Milênio, y BRS Urubuquara fueron altamente susceptibles a S. eridania.

Diante da crescente importância de Cerotoma arcuata nos últimos anos, devido aos prejuízos econômicos causados à cultura da soja, ausência de inseticidas registrados no Brasil e escassez de informações a respeito de cultivares resistentes, este trabalho objetivou avaliar a preferência alimentar de adultos e o desenvolvimento pós-embrionário de C. arcuata, em cultivares e linhagem de soja, visando a encontrar possíveis fontes de resistência. Utilizaram-se as cultivares comerciais BRSMG 750 SRR, M-SOY 7908 RR e P 98Y30 RR e a linhagem PI 274454 (padrão de resistência a partir de resultados com Diabrotica speciosa). No teste de preferência alimentar com e sem chance de escolha, foi avaliada a atratividade em diferentes tempos, após a liberação dos adultos, e a área foliar consumida, ao final do experimento. No teste de antibiose, foram avaliados o período e a viabilidade de desenvolvimento pós-embrionário, massa de adultos, razão sexual e longevidade de adultos sem alimento. Em geral, não houve diferenças na atratividade para os adultos e área foliar consumida entre as cultivares e linhagem de soja. Apenas a longevidade dos adultos foi maior na linhagem PI 274454 e menor na cultivar BRSMG 750 SRR. As cultivares comerciais de soja não apresentaram resistência dos tipos não preferência para alimentação ou antibiose a C. arcuata, e a linhagem PI 274454 não deve ser utilizada como padrão de resistência, em testes de resistência a esta espécie.

Considering the increasing importance of Cerotoma arcuata in the last years, due to the economical losses caused on soybean crop, absence of insecticides registered in Brazil and lack of information about resistant cultivars, this study aimed to assess the feeding preference of adults and postembryonic development of C. arcuata on soybean cultivars and breeding line, in an attempt to find potential sources of resistance. The BRSMG 750 SRR, M-SOY 7908 RR and P 98Y30 RR commercial cultivars and the PI 274454 breeding line (used as the resistance standard from results obtained with Diabrotica speciosa) were used. In both the free-choice and no-choice feeding preference test, the attractiveness in different times, after releasing the adults, and the leaf area consumed at the end of the experiment were evaluated. In the antibiosis assay, the period and viability of the postembryonic development, weight of adults, sex ratio and longevity of adults without feeding were assessed. Overall, there were no differences in the attractiveness of the adults and leaf area consumed between the soybean cultivars and breeding line. Only the longevity of adults was longer on the PI 274454 breeding line and shorter on the BRSMG 750 SRR cultivar. The soybean commercial cultivars did not present resistance of the non-preference for feeding or antibiosis kinds to C. arcuata, and the PI 274454 breeding line must not be used as a resistance standard in resistance assays against this species.

Lagartas do gênero Spodoptera spp. são altamente polífagas, podendo causar danos econômicos em diversas culturas agrícolas. Em vista de sua emergente importância na cultura do tomate, principalmente o destinado à indústria, este trabalho teve por objetivo avaliar a não preferência, para alimentação, de lagartas de Spodoptera frugiperda (J. E. Smith, 1797) e Spodoptera eridania (Cramer, 1782) por genótipos de tomateiro, e classificá-los quanto aos graus de resistência. Como padrão susceptível, utilizou-se o cultivar comercial Santa Clara e, como resistente, a linhagem PI 134417, sendo avaliadas, ainda, as linhagens PI 134418, PI 126931, LA 462 e LA 716. Realizaram-se testes de não preferência, para alimentação, com e sem chance de escolha, avaliando-se a atratividade dos genótipos de tomateiro para as lagartas, em tempos pré-estabelecidos após sua liberação, além da massa foliar consumida. Em geral, os genótipos LA 716 e PI 126931 foram os menos atrativos para a S. frugiperda, enquanto Santa Clara foi o mais atrativo e consumido. Quanto a S. eridania, os genótipos PI 126931, LA 462, LA 716 e PI 134418 foram os menos preferidos, para a alimentação, pelas lagartas, e Santa Clara e PI 134417 foram os mais atrativos e consumidos. Os genótipos LA e PI 126931 são moderadamente resistentes, do tipo não preferência para alimentação, para a S. frugiperda e S. eridania; PI 134418 e LA 462 são moderadamente resistentes a S. eridania; PI 134417 é susceptível a S. frugiperda e S. eridania; Santa Clara é altamente susceptível a S. frugiperda e S. eridania.

Larvae of the genus Spodoptera spp. are highly polyphagous and can cause economical losses in several agricultural crops. Given their growing importance in the tomato crop, especially for industry, this work aimed to evaluate the feeding non-preference by larvae of Spodoptera frugiperda (J. E. Smith, 1797) and Spodoptera eridania (Cramer, 1782) on tomato genotypes and classify them by the levels of resistance. The commercial cultivar Santa Clara was set as the susceptible standard and line PI 134417 as the resistant standard to evaluate the lines PI 134418, PI 126931, LA 462 and LA 716. Feeding non-preference tests were performed under non-choice and free-choice conditions to evaluate the genotype attractiveness to larvae at predetermined times after their release, as well as the leaf area consumed. Overall, the genotypes LA 716 and PI 126931 were the least attractive to S. frugiperda, whereas Santa Clara was the most attractive and consumed. For S. eridania, the genotypes PI 126931, LA 462, LA 716 and PI 134418 were the least preferred for feeding, and Santa Clara and PI 134417 were the most attractive and consumed. The genotypes LA 716 and PI 126931 are moderately resistant to S. frugiperda and S. eridania; PI 134418 and LA 462 are moderately resistant to S. eridania; PI 134417 is susceptible to S. frugiperda and S. eridania; and Santa Clara is highly susceptible to both S. frugiperda and S. eridania.

Este trabajo tuvo como objetivo encontrar genotipos de soya con baja preferencia para alimentación por larvas de Spodoptera eridania en 23 genotipos evaluados en tres experimentos, de los cuales IAC 100 se estableció como el genotipo resistente y BR 16 como el susceptible. De los resultados obtenidos en estas pruebas, se realizó un experimento final con los 10 genotipos más destacados: IAC 100, PI 227682, PI 227687, DM 339, P 98Y51 RR, BRSGO 8360, IGRA RA 518 RR, IGRA RA 516 RR, IGRA RA 626 RR y BR 16. En todos los experimentos, se realizaron pruebas con y sin opción de elección. En el primer caso, se pusieron los discos foliares relacionados a los genotipos en placas de Petri y se liberó una larva de tercer estadio por genotipo. En el segundo, se utilizó un disco de cada genotipo por placa donde se liberó una larva de tercer estadio. La atracción de las larvas de tercer estadio además del área foliar consumida por las mismas se evaluaron a 1, 3, 5, 10, 15, 30, 60, 120, 360, 720 y 1080 minutos después de su liberación. En ambas pruebas el genotipo IAC 100 fue el menos atractivo y consumido por las larvas, mientras que el BRSGO 8360 y P 98Y51 RR fueron los más consumidos en las pruebas con y sin elección, respectivamente. El genotipo IAC 100 fue altamente resistente a S. eridania en experimentos de preferencia alimenticia y por lo tanto puede ser cultivado o incorporado en programas de mejoramiento con el fin de obtener plantas de soya con características de resistencia a esta plaga.

This work aimed to find soybean genotypes with low feeding preference by Spodoptera eridania larvae on 23 genotypes evaluated in three experiments, of which IAC 100 was established as the resistant genotype and BR 16 as the susceptible genotype. From the results obtained in these tests, a final experiment was carried out with the 10 most outstanding genotypes: IAC 100, PI 227682, PI 227687, DM 339, P 98Y51 RR, BRSGO 8360, IGRA RA 518 RR, IGRA RA 516 RR, IGRA RA 626 RR and BR 16. In all experiments, free choice and no choice tests were performed. In the former, leaf discs corresponding to the genotypes were placed in Petri dishes and then one third-instar larva per genotype was released. In the latter we used one leaf disc of each genotype per plate where one third-instar larva was released. The attractiveness of the third-instar larvae was evaluated at 1, 3, 5, 10, 15, 30, 60, 120, 360, 720 and 1080 minutes after their release, as well as the leaf area consumed. In both tests the genotype IAC 100 was the least attractive and consumed by the larvae, whereas BRSGO 8360 and P 98Y51 RR were the most consumed in free choice and no choice tests, respectively. Genotype IAC 100 was highly resistant to S. eridania in feeding preference experiments and thus can be cultivated or incorporated into breeding programs in order to obtain soybean plants with resistance characteristics to this pest.