Multiple resistance to primary pests of grain sorghum hybrids: Spodoptera frugiperda (Lepidoptera: Noctuidae), Diatraea saccharalis (Lepidoptera: Crambidae), and Diceraeus melacanthus (Hemiptera: Pentatomidae)

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.

Resistance of rice genotypes to fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

ABSTRACT The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is an important rice pest which consumes leaf area during all phases of plant development. The objective of this study was to identify rice genotypes that provide antixenosis and antibiosis to fall armyworm. Antixenosis was investigated by measuring non-preference in free-choice and no-choice tests while antibiosis was determined by measuring biological parameters and nutritional indices of S. frugiperda in twelve rice genotypes. The genotype Miúdo Branco showed antixenosis to S. frugiperda, whereas the genotypes IR 64 and Bacaba Branco showed antibiosis to S. frugiperda by affecting insect development and prolonging insect life cycle. Insects that fed on Bacaba Branco genotype demonstrated the lowest nutritional indices. Since Miúdo Branco, IR 64 and Bacaba Branco showed moderate resistance, rice producers could use these genotypes as part of a control strategy for S. frugiperda.

Antibiosis and antixenosis resistance to oviposition by Bemisia tabaci (Gennadius) B biotype (Hemiptera: Aleyrodidae) in soybean genotypes / Antibiose e antixenose para oviposição da Bemisia tabaci (Gennadius) Biótipo B (Hemiptera: Aleyrodidae) em genótipos de soja

This study was aimed at assessing some biological parameters of Bemisia tabaci B biotype at immature stages to examine antibiosis in six soybean genotypes, besides antixenosis resistance to oviposition in choice and non-choice tests, under greenhouse and laboratory conditions. Between April 2016 and August 2016, bioassays were carried out at the Laboratory of Applied Entomology at College of Agricultural Sciences at Federal University of Grande Dourados (UFGD) Dourados (MS), Brazil. The following variables were evaluated: egg incubation period, nymphal and egg-to-adult duration, egg and nymph viability, and egg-to-adult survival on the soybean genotypes 68i70 RSF IPRO, M6210 IPRO, MS 947 IPRO, BMX Potência RR, M6410 IPRO, and ANTA 82 RR. Antixenosis resistance to oviposition by the silverleaf whitefly was found for MS 947 IPRO, while oviposition was highest for ANTA 82 RR, M6210 IPRO, and M6410 IPRO. The genotype MS 947 IPRO adversely affected egg and nymph viability, and egg-to-adult survival rates was the lowest among genotypes (59.75%), suggesting antibiosis resistance to this pest.(AU)

Este trabalho teve por objetivo avaliar a antibiose em seis genótipos de soja da Bemisia tabaci biótipo B mediante alguns parâmetros biológicos das fases imaturas do inseto, assim como analisar a resistência do tipo antixenose para oviposição em testes com e sem chance de escolha, em laboratório e casa de vegetação. Os ensaios foram conduzidos no Laboratório de Entomologia Aplicada da Faculdade de Ciências Agrárias da Universidade Federal da Grande Dourados (UFGD), Dourados (MS), entre os meses de abril e agosto de 2016. As variáveis averiguadas foram: período de incubação dos ovos; período ninfal; duração de ovo a adulto; viabilidade de ovo; viabilidade de ninfa e sobrevivência de ovo a adulto. Os genótipos de soja avaliados foram: 68i70 RSF IPRO, M6210 IPRO, MS 947 IPRO, BMX Potência RR, M6410 IPRO e ANTA 82 RR. O genótipo que apresentou antixenose para oviposição da mosca-branca foi o MS 947 IPRO, e constatou-se que o maior número de postura foi realizado nos genótipos ANTA 82 RR, M6210 IPRO e M6410 IPRO. O genótipo MS 947 IPRO também afetou negativamente a viabilidade de ovos e ninfas, bem como a sobrevivência de ovo a adulto, com as menores porcentagens de sobrevivência (59,75%), indicando possível resistência do tipo antibiose à mosca-branca.(AU)

Oviposition preference and larval performance of sugarcane borer in eight sugarcane genotypes / Preferência de oviposição e desempenho larval da broca-da-cana em oito genótipos de cana-de-açúcar

ABSTRACT The sugarcane borer Diatraea saccharalis Fabr. (Lepidoptera: Crambidae) is one of the most important pests of sugarcane in the Americas. The purpose of this study was to assess multiple resistance traits in eight sugarcane genotypes against D. saccharalis, including five commercial cultivars and three exotic germplasm with potential to serve as resistance sources against this pest. The oviposition preference was assessed by using both free-choice and non-choice tests. The performance of both early stage larvae feeding on the leaves and late stages larvae feeding within the stalks were also assessed. There were differences among genotypes for number of both eggs and egg cluster in the free-choice test while no differences in non-choice test were observed. There were also differences in survival of early stage larvae feeding on the leaves, foliar injury rating and stalk damage. The genotype IM76-228 was the least preferred for oviposition and it seems that leaf width had some influence on adults' preference rather than greening of the leaves. IM76-228 and RB867515 causes higher mortality of early stage larvae feeding in the stalks while IM76-228 and RB985523 had lower damage in both leaves and stalks. The genotype IM76-228 was the most resistant to D. saccharalis and could serve as genes sources for resistance in sugarcane breeding programs.

RESUMO A broca da cana-de-açúcar Diatraea saccharalis Fabr. (Lepidoptera: Crambidae) é uma das mais importantes pragas da cana-de-açúcar nas Américas. Este estudo foi realizado para investigar múltiplos traços de resistência em oito genótipos de cana-de-açúcar contra D. saccharalis, incluindo cinco cultivares comerciais e três germoplasmas exóticos com potencial para servir de fontes de resistência contra esta praga. A preferência de oviposição foi avaliada por meio de testes de escolha livre e de não-escolha. O desempenho de larvas de estágio inicial que se alimentam das folhas e de larvas de estádio tardio alimentando-se com os colmos também foi avaliado. Houve diferenças entre os genótipos para o número de ovos e posturas no teste de livre escolha, enquanto não foram observadas diferenças no teste de não-escolha. Houve também diferenças na sobrevivência de larvas de estádios iniciais que se alimentam das folhas, índice de lesões e dano no colmo. O genótipo IM76-228 foi o menos preferido para a oviposição e parece que a largura da folha teve alguma influência sobre a preferência dos adultos em vez da intensidade de verde das folhas. IM76-228 e RB867515 provocaram uma mortalidade mais elevada de larvas de estádio inicial alimentando-se dos colmos, enquanto que IM76-228 e RB985523 apresentaram menor dano nas folhas e nos colmos. O genótipo IM76-228 foi o mais resistente a D. saccharalis e pode servir como fonte de genes para resistência em programas de melhoramento de cana-de-açúcar.

Caracterização de cultivares de amendoim quanto ao dano de Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae) / Characterization of peanut cultivars to damage Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae)

Avaliou-se a resistência de quatro cultivares de amendoim de hábito de crescimento rasteiro e cinco cultivares de hábito de crescimento ereto ao dano de Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae) em condições de campo na safra das águas, nos anos 2009/2010 e 2010/2011. Os cultivares utilizados nos experimentos foram: IAC 147, IAC 213, IAC Caiapó e IAC Runner 886 (porte rasteiro) e IAC Tatu ST, IAC 5, IAC 8112, IAC 22 e IAC 88-1 (porte ereto). O delineamento adotado foi em blocos ao acaso, com parcelas subdivididas ao longo do tempo, e quatro repetições. Para a infestação de S. bosquella , foram realizadas avaliações semanais dos 18 aos 67 dias após a emergência (DAE), com contagem de lagartas e avaliações de danos. Para a contagem do número de brotos por planta, coletaram-se 5 plantas por parcela a partir dos 30, 60 e 90 DAE. Independentemente do cultivar, as maiores infestações de S. bosquella ocorrem dos 53 aos 67 DAE. O cultivar IAC Runner 886 apresenta a maior emissão de brotos apicais, uma característica desejável na defesa da planta em relação à S. bosquella.(AU)

We evaluated the strength of four growth habit of peanut cultivars creeping and five cultivars of erect growth habit to damage Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae) under field conditions during the rainy season, in the years 2009/2010 and 2010/2011. The cultivars used in the experiments were: IAC 147, IAC 213, IAC Caiapó and IAC Runner 886 (runner) and IAC Tatu ST, IAC 5, IAC 8112, IAC 22 e IAC 88-1 (erect). The design adopted was randomized blocks with split plot over time, and four replications. For infestation of S. bosquella , weekly evaluations were done 18 to 67 days after emergence (DAE), with caterpillars count and damage assessments. For counting the number of shoots per plant, they collected up five plants per plot from the 30, 60 and 90 DAE. Regardless of cultivating major infestations of S. bosquella occur from 53 to 67 DAE. The IAC Runner 886 cultivar has the highest emission apical shoots a desirable feature in plant defense in relation to S. bosquella.(AU)

Biologia de Mahanarva fimbriolata em gramíneas forrageiras / Biology of Mahanarva fimbriolata on forage grasses

Estudou-se a biologia de Mahanarva fimbriolata nas gramíneas Setaria anceps cv. 'Kazungula', Brachiaria brizantha cv. 'Marandu', ecótipos BB 33, BB 39, seleções IAC-BBS 5 e IAC-BBS 8, e cana-de-açúcar. 'SP-80-1842' (testemunha) em laboratório, visando a avaliar a resistência desses genótipos a essa praga. Os parâmetros avaliados foram: mortalidade e duração da fase de ninfa, razão sexual, período de pré-oviposição, número de ovos por fêmea, longevidade, duração e viabilidade da fase embrionária. Constatou-se maior mortalidade e prolongamento na fase de ninfa em IAC-BBS 8, B. brizantha cv. 'Marandu' e S. anceps cv. 'Kazungula'. Os menores valores de longevidade e fecundidade foram verificados em IAC-BBS 8 e IAC-BBS 5 e os maiores em cana-de-açúcar. A menor viabilidade da fase embrionária foi obtida em IAC-BBS 5 e a maior em IAC-BBS 8. Segundo os resultados da tabela de vida, a taxa líquida de reprodução (Ro) e a taxa finita de crescimento (λ) foram menores em IAC-BBS 8. Concluiu-se que IAC-BBS 8 é o genótipo mais resistente a M. fimbriolata, sendo a resistência do tipo antibiose e/ou não-preferência para alimentação.

Under controlled conditions, six forage grasses (Setaria anceps cv. 'Kazungula' and Brachiaria brizantha cv. 'Marandu'; and codified genotypes BB33, BB39; BBS 5 and BBS8), along with a control check (sugarcane cv. 'SP80-1842') were evaluated as to Mahanarva fimbriolata resistance. The following parameters have been evaluated: nymphal phase duration and mortality, sex ratio, pre-oviposition period, number of eggs per female, longevity, viability and embryonic period. The highest mortalities and longer nymphal periods occurred on BBS 8, cv. 'Marandu' and cv. 'Kazungula'. BBS5 also caused high nymph mortality, however with the shortest nymphal period. The lowest longevity and fecundity values were detected for BBS5 and BBS8, whereas the sugarcane control check revealed the highest one. As to embryonic phase viability, BBS 8 originated the highest values and BBS 5, the lowest ones. Among the tested plants, BBS 8 along with the cv. 'Marandu', proved to be the most resistant genetic material, both through antibiosis and/or nonpreference for feeding mechanism.

Screening of maize genotypes against stem borer chilo partellus l. in kharif season.

Maize (Zea mays L.) being the highest yielding cereal crop in the world is of significant importance for countries like India, where rapidly increasing population already out stripped the available food supplies. Maize crop possesses great genetic diversity. Maize Plant is attacked by 140 species of insects causing varying degree of damage causing an annual loss of over 1 billion in the Semi Arid Tropics (ICRISAT, 1992). Out of these, only 10 species cause serious damage from sowing till storage, of which the stemborer Chilo partellus (Swinhoe) is the major one (Hiremath et al., 1988). The larvae of C.partellus after hatching feed on soft surface of the leaves and then enter the stem through whorl of feeding on the pith of the stem. The growth of the plants becomes shunted and resulting in dead hearts when attacked by C.partellus at their initial stages. The larvae transferred from other plants enter the stem through lower nodes by making the holes. Stem borers pupate inside the stem. They make holes before pupation for the emergence of adults. Since host plant resistance is the back bone of Insect Pest Management; hence the present investigation was initiated. Present studies were designed to identify maize genotype resistance against stem borer in order to minimize pesticide use, improve natural balance, and enhance the activity of bio control agents, and to increase crop production. The investigations were carried out on the screening of Maize genotypes against Maize stem borer Chilo partellus in kharif season were conducted on the agricultural farm of the institute of Agricultural Sciences, Banaras Hindu University, Varanasi during kharif season of 2010-2011 to screen the relative resistance /susceptibility of 19 genotypes of maize to the insect pest, maize stem borer (Chilo partellus). In order to screen the relative susceptibility of different maize genotypes to maize stem borer the following genotypes were screened under field conditions. The symbols T1 to T19 have been used to represent the following cultivars of maize. HUZM 217, HUZM 185, HUZM 227, HUZM 186, AH 411, NMH 9858, HUM 152, CM 119, QPM 466, QPM 467, QPM 169, QPM 193, QPM 163, HUZQPM 240, HUZQPM 241, HUZQPM 242, HUZQPM 243, HUZQPM 246, HUZQPM 247. The maize varieties were grown in plots having 19 rows, plot size 13x2.5 m². The plant spacing between rows and plants were maintained 70 cm and 20 cm, respectively. The crop was grown as per the normal agronomic practices during the kharif season of 2010-2011. The effect of natural infestation was studied. The crop was sown on 22nd July 2010 and harvested on 10th November 2010. Entire screening was based on leaf damage, dead heart formation, no. of exit holes. No. of larvae and pupae population and mean tunnel length. Dead heart formations were higher in more susceptible genotypes than least susceptible genotypes. There were no sign of dead heart was found in cultivar HUZQPM 242, HUZQPM 246, QPM 193, CM 119, AH 411, HUM 152, NMH 9858, HUZM 185, HUZM 217. Maximum occurrences of dead heart were in cultivar HUZM 227, QPM 169. Leaf damage was measured on visual rating scale. In context of leaf injury rating mean was 2.6 to 6.6. Maximum leaf damage was reported on cultivar QPM 169.Average plant height was mean of length from root to flag leaf. Mean tunnel length was divided into three categories-Least susceptible (0-5cm), moderately susceptible (5-10cm), highly susceptible (>10 cm) and respected genotypes also have been identified.

Efeito de cultivares de repolho e doses de extrato aquoso de nim na alimentação e biologia de Plutella xylostella (Linnaeus) (Lepidoptera: plutellidae) / Effect of cabbage cultivars and doses of aqueous extrat of neem on feeding and biology of Plutella xylostella (linnaeus) (lepidoptera: plutellidae)

Avaliaram-se os efeitos isolados e associados das cultivares de repolho Ruby Ball e Chato de Quintal e o extrato aquoso de amêndoas de frutos de nim (Azadirachta indica A. Juss.) nas concentrações de 5 e 10% sobre a atratividade, alimentação e desenvolvimento de Plutella xylostella (L.). No teste de não preferência para alimentação com chance de escolha, discos foliares de cada tratamento foram dispostos em placas de Petri onde foram liberadas três lagartas/tratamento, enquanto no teste sem chance de escolha duas lagartas foram colocadas em placas de Petri contendo um disco foliar em cada placa. No teste de biologia, lagartas recém-eclodidas foram transferidas para placas de Petri, na proporção de uma por placa, onde foram avaliados os parâmetros biológicos: mortalidade larval após 1, 3 e 5 dias; mortalidade pupal; mortalidade total; peso de lagartas com seis dias de idade; peso de pupas com 24 horas de idade; e longevidade de adultos. A cultivar Ruby Ball apresentou menor atratividade às lagartas no teste com chance de escolha. O extrato de nim em ambas as concentrações foi considerado repelente no teste com chance de escolha. Não houve diferença na massa foliar seca consumida pelas larvas, nos testes com e sem chance de escolha. Também não foi observada diferença na mortalidade larval, pupal e total entre as cultivares. Ambas as doses do extrato de nim foram igualmente eficientes na mortalidade da traça-das-crucíferas. Não houve diferença do peso de lagartas e pupas e da longevidade dos adultos de P. xylostella entre as cultivares.

The isolated and associated effects of cabbage cultivars Ruby Ball and Chato de Quintal and aqueous extract of seeds of fruits of neem (Azadirachta indica A. Juss.) were evaluated in the concentrations of 5 and 10% on Plutella xylostella (L.) attractiveness, feeding and development. In free-choice no-preference for feeding test, leaf discs of each treatment were placed in Petri dishes where three caterpillars/treatment were released while in no-choice test two caterpillars were placed in Petri dishes with one leaf disc in each dish. In the biology test, neonate larvae were transferred to Petri dishes in the proportion of one per dish, whereas the biological parameters were evaluated: larvae mortality after 1, 3 and 5 days; pupae mortality; total mortality; six day-old larvae weight; 24 hour-old pupae; and adult longevity. Cultivar Ruby Ball showed lower attractiveness to the caterpillars in free-choice test. Neem extract in both concentrations was repellent to the caterpillars in free-choice test. There were no differences in the dry mass consumed by the caterpillars in free-choice and no-choice tests. There were no differences in larval, pupal and total mortality between the cultivars. Both doses of neem extract were equally efficient in the mortality of the diamondback moth. There were no differences in caterpillars and pupae weight and in the longevity of the adults of P. xyostella between the cultivars.

Effect of gossypol on survival and reproduction of the zoophytophagous stinkbug Podisus nigrispinus (Dallas)

Effect of gossypol on survival and reproduction of the zoophytophagous stinkbug Podisus nigrispinus (Dallas). Gossypol is a sesquiterpene aldehyde found in cotton plants conferring resistance against herbivory. Although the effect of this sesquiterpenoid on insect pests of cotton is known, the interaction of this compound with zoophytophagous predators such as Podisus nigrispinus (Dallas) (Hemiptera, Pentatomidae) has not been studied so far. Thus, the objective of this study was to evaluate the effect of the purified gossypol on nymphs and adults of P. nigrispinus. Nymphs and adults of this predator were fed on Tenebrio molitor pupae and supplemented with solutions of gossypol at concentrations of 0.00, 0.05, 0.10, and 0.20 percent (w/v) during the nymphal and adult stages or, only during the adult stage of P. nigrispinus. The nymphal stage of the predator was, on average, two days longer when suplemmented with gossypol. Emerged adults had lower fecundity and egg hatching, especially at the highest gossypol concentration (0.20 percent) ingested during the nymphal and adult stages. However, this predator was not affected when it ingested the compound only during the adult stage. P. nigrispinus can have delayed nymphal development and lower reproductive performance when ingesting the gossypol during the nymphal and adult stages, but only at higher concentrations of gossypol than that produced by cotton plants.

Efeito do gossipol na sobrevivência e reprodução do percevejo zoofitófago Podisus nigrispinus (Dallas). O gossipol é um aldeído sesquiterpeno produzido pelo algodoeiro que confere resistência contra a herbivoria. A interação deste sesquiterpeno com predadores zoofitófagos, como Podisus nigrispinus (Dallas) (Hemiptera, Pentatomidae), é inexistente apesar do reconhecido efeito do gossipol sobre insetos pragas do algodoeiro. Assim, este estudo avaliou o efeito do extrato de gossipol sobre ninfas e adultos de P. nigrispinus. O predador foi alimentado com pupas de Tenebrio molitor L. (Coleoptera, Tenebrionidae) e suplementado com soluções do gossipol nas concentrações 0, 0,05, 0,10 e 0,20 por cento (peso/volume) durante os estágios ninfal e adulto e somente durante o estágio adulto. A duração do estágio ninfal do predador foi em média dois dias mais longo quando suplementado com gossipol. Adultos oriundos de ninfas suplementadas com gossipol apresentaram menor fecundidade e viabilidade dos ovos, em especial na maior concentração (0,20 por cento). Contudo, adultos não foram afetados quando suplementados com gossipol somente durante este estágio. Os resultados demonstram que a ingestão prolongada do gossipol ocasiona efeito no desenvolvimento e reprodução do predador P. nigrispinus, porém somente em concentração superior àquela produzida naturalmente pela planta de algodão.

Resistance of Soybean Genotypes to Bemisia tabaci (Genn.) Biotype B (Hemiptera: Aleyrodidae)

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B has become a serious problem for soybean cultivation because it can significantly reduce soybean productivity. The use of soybean cultivars resistant to whitefly attack is an important strategy in an integrated pest management (IPM) program. This study evaluated the preference for oviposition and colonization by B. tabaci biotype B on different soybean genotypes. In the free-choice test, the genotypes studied were 'IAC 17' and 'IAC 19' as the standards for resistance and 'IAC Holambra Stwart' as the standard for susceptibility, as well as BABR01-0492, BABR01-0173, BABR01-1259, BABR01-1576, BABR99-4021HC, BABR99-4021HP, 'Barreiras', 'Conquista', 'Corisco', 'BRS Gralha', PI274454, PI227687, and PI171451. In the no-choice test, the four best genotypes selected in the free-choice test, in addition to the susceptible and resistant standards were evaluated. Our data indicated 'Barreiras' as the most resistant genotype against B. tabaci biotype B. 'BRS Gralha', which was the least attractive to whitefly adults in the free-choice test, did not show resistance to insect attack when they were confined in cages in the no-choice test. Despite the high number of eggs observed, BABR01-1576 and BABR99-4021HC showed a reduced number of nymphs, indicating antibiosis. The genotypes with a high level of resistance can be used as a tool against B. tabaci in IPM or as a source of resistance in plant-breeding programs.

Resistência de genótipos de feijoeiro a Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae) / Resistance of genotypes to Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae)

Durante o armazenamento de grãos de feijão (Phaseolus vulgaris L.), o rendimento pode ser reduzido devido às infestações de carunchos como os da espécie Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae). O ataque desse inseto afeta diretamente a qualidade dos grãos, além de facilitar a entrada de patógenos, tornando-os inviáveis para o consumo e/o comércio. Com a finalidade de buscar uma estratégia alternativa para o controle deste caruncho, avaliou-se a possível resistência de linhagens quase isogênicas contendo arcelina, linhagens selvagens contendo arcelina e cultivares comerciais de feijoeiro, em laboratório (T= 25±2° C, U.R.= 70±10 por cento e fotoperíodo= 12h). Foram utilizados frascos contendo 10 g de grãos dos genótipos, os quais foram infestados por uma semana com sete casais do caruncho. Vinte e um dias após a infestação, os grãos foram avaliados contando-se o número de ovos viáveis. A partir de 25 dias da infestação, os grãos foram observados diariamente avaliando-se o número e o peso dos insetos emergidos, a viabilidade larval, o ciclo biológico (ovo-adulto) e o peso de grãos consumidos. Empregou-se um delineamento inteiramente casualizado, com oito repetições. Os genótipos Arc.2, Arc.3, Arc.4, Arc.3S e Ipa 6 expressaram baixos níveis de não-preferência para oviposição e foram classificados como deterrentes. Os genótipos Arc.1S e Arc.1 expressaram elevados níveis de antibiose; Arc.2, Arc.3 e Arc.4 apresentam o mesmo mecanismo, porém, em níveis inferiores.

During the storage of bean grains (Phaseolus vulgaris L.), production may be reduced due to weevils attack such as the species Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae). This insect attack affects directly the quality of grain and facilitates the entry of pathogens, making them impractical for consumption and trade. In order to find an alternative strategy to control of this pest, we assessed the possible resistance of near isogenic lines containing arcelin, wild lines containing arcelin and cultivars, in laboratory (T= 25±2° C, R.H.= 70±10 percent and photoperiod= 12h). The assays were conducted in vials containing 10g of bean grains per genotype, releasing seven pairs of the insect and maintaining the infestation during one week. Twenty-one days after the releasing, the grains were evaluated counting the viable eggs. Twenty-five days after the infestation, the evalutions were daily initiated, observing the number of adults emerged, larvae viability, development period (egg to adult) and weight of grains consumed. The assays were performed in a completely randomized design with eight replicates. The genotypes Arc.2, Arc.3, Arc.4, Arc.3S and Ipa 6 showed low levels of oviposition non-preference, being classified as deterrents. The genotypes Arc.1S and Arc.1 expressed high levels of antibiosis; Arc.2, Arc.3 and Arc.4 showed the same mechanism, however in lower levels.

Resistência de cultivares de batata a Myzus persicae (Sulz.)(Hemiptera: Aphididae) / Resistance of potato cultivars to Myzus persicae (Sulz.) (Hemiptera: Aphididae)

Aphids are the most important vectors of viruses infecting potato (Solanum tuberosum). We focused on the response of the aphid vector Myzus persicae (Sulzer) to five commercial potatocultivars: Ágata, Jaette Bintje, Mondial, Monalisa and Santè, by traditional antibiosis and antixenosis tests and by the EPG (Electrical Penetration Graph) technique, as a step forward to the design of effective management practices. Our aim was to identify plant factors involved in resistance of these cultivars against M. persicae, both at the surface and in deeper plant tissues. Results from the antixenosis test confirmed a strong preference of M. persicae for the Mondial cultivar. The antibiosis study indicated a lower population development of the aphid in 'Monalisa' when compared to 'Ágata' and 'Jaette Bintje'. EPG assays indicated that 'Santè' inhibited the initial feeding process of M. persicae, whereas 'Monalisa' showed a physical-type of resistance as demonstrated by a very high number of short probes. The cultivar Mondial showed average values for all EPG variables analyzed. The behavior in 'Jaette Bintje' indicated this cultivar was an ideal host for aphid feeding and reproduction. Together, the EPG data revealed the existence of pre and post-phloematics factors in the cultivars under study, which have important implications on the efficiency of transmission and spread of virus in potato by M. persicae.

Comportamento de genótipos de feijoeiro ao ataque de Bemisia tabaci (Genn) biótipo B (Hemiptera: Aleyrodidae) / Behavior of bean genotypes to attack by Bemisia tabaci (Genn) biotype B (Hemiptera: Aleyrodidae)

Avaliou-se o comportamento de genótipos de feijoeiro sob infestação de Bemisia tabaci (Genn.) biótipo B em condições de campo, nas épocas de cultivo "da seca" e "das águas". Utilizaram-se os genótipos IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRS-Pontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 e Z-28. Adotou-se o delineamento de blocos casualizados com 14 tratamentos e três repetições. As avaliações foram realizadas semanalmente, contando-se o número de ovos e de ninfas de B. tabaci biótipo B em dez folíolos por parcela. Na safra "da seca" os genótipos menos ovipositados por B. tabaci biótipo B foram IAC-Una e LP 02-130 e os mais ovipositados foram os genótipos Z-28 e Pérola. As menores presenças de ninfas de mosca-branca foram observadas em LP 98-122 e FT-Nobre e as maiores em LP 01-38, Pérola e Z-28. Para a safra "das águas" os genótipos não diferiram entre si em relação ao ataque de B. tabaci biótipo B. Os fatores da produção apresentaram diferença estatística somente na safra das secas.

Bean genotypes were evaluated under the infestation of Bemisia tabaci (Genn.) biotype B under field conditions in the dry and rainy season. The genotypes used were IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRSPontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 and Z-28. The experiment was arranged in randomized blocks with 14 treatments and 3 replications. The evaluations were made on a weekly basis by counting B. tabaci biotype B eggs and nymphs on 10 leaflets per plot. In the dry season the least oviposited genotypes by B. tabaci biotype B were IAC-Una and LP 02-130, while the most oviposited were Z-28 and Pérola. The least presence of nymphs of whitefly was observed on LP 98-122 and FT-Nobre, and the most on LP 01-38, Perola and Z-28. For the rainy season the genotypes did not differ in relation to the attack of B. tabaci biotype B. The yield factors presented a statistical difference only in the dry season.

Não-preferência para oviposição e alimentação de Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) por cultivares de amendoim / Non-oviposition and non-feeding preference of Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) for peanut cultivars

Este trabalho buscou selecionar cultivares de amendoim resistentes a Spodoptera frugiperda, dos tipos não-preferência para oviposição e alimentação, em testes com e sem chance de escolha. Utilizaram-se cultivares de amendoim de hábitos de crescimento ereto (IAC 5, IAC 8112, IAC 22 e IAC Tatu ST) e rasteiro (IAC 503, IAC 505, IAC 147, IAC 125, IAC Caiapó e IAC Runner 886). Os testes de não-preferência para oviposição foram realizados com adultos recém-emergidos, os quais foram alimentados com solução de mel a 10%, permanecendo nas gaiolas por quatro dias até o início das avaliações. Estas consistiram na quantificação do número de ovos e posturas, com posterior cálculo do número de ovos por postura. Para os testes de não-preferência para alimentação foram colocados discos foliares das cultivares em placas de Petri, liberando uma lagarta de terceiro ínstar por cultivar. Avaliou-se a atratividade a 1, 5, 10, 15, 30, 60, 120, 360, 720; 1.440 minutos, contando-se o número de lagartas que se alimentavam nas cultivares e, ao término do experimento, quantificou-se a área foliar consumida por cultivar. Nos testes de não-preferência para oviposição ou alimentação, com ou sem chance, nenhuma cultivar de hábitos de crescimento ereto ou rasteiro influenciou a oviposição ou alimentação de S. frugiperda. Dessa maneira, as cultivares de amendoim não apresentaram resistência dos tipos não-preferência para oviposição e alimentação.

This study aimed to select peanut cultivars resistant to Spodoptera frugiperda, selecting non-oviposition and non-feeding preference in choice and no-choice tests. Peanut cultivars with upright growth habit (IAC 5, IAC 8112, IAC 22 and IAC Tatu ST) and runner growth habit (IAC 503, IAC 505, IAC 147, IAC 125, IAC Caiapó and IAC Runner 886) were evaluated. Tests of non-oviposition preference were conducted with newly emerged adults. Adults were fed a 10% honey solution, remaining in cages for 4 days until the start of the evaluations. The evaluations consisted of quantifying the number of eggs and egg masses, followed by calculating the number of eggs per egg mass. To perform non-feeding preference tests, leaf discs from different peanut cultivars were placed in disposable Petri dishes followed by releasing of a third-instar caterpillar for each cultivar. The attractiveness at 1, 5; 10, 15, 30, 60, 120, 360, 720 and 1,440 minutes was evaluated by counting the caterpillars that were feeding on cultivars. The leaf area consumed was evaluated at the end of the experiment for each cultivar. In the tests of non-oviposition and non-feeding preference, with choice or no-choice, none of the cultivars of the upright growth and runner growth habit influenced the oviposition or food of S. frugiperda. Thus, the peanut cultivars showed no resistance of the non-feeding and non-oviposition types.

Seleção de genótipos resistentes de amendoinzeiro a Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) com base em análises multivariadas / Selection of resistant peanut genotypes to Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) supported by multivariate analysis

The velvetbean caterpillar Anticarsia gemmatalis Hübner attacks peanut leaves, and the use of resistant varieties has directly contributed to ecological and economic aspects of pest control. The aim of this work was to select resistant peanut genotypes to A. gemmatalis using cluster analyses (dendogram obtained by Ward's methods and K-means) and Principal Components analysis for data interpretation. The evaluated genotypes were: IAC 5, IAC 8112, IAC 22 and IAC Tatu ST with upright growth habit, and IAC 147, IAC 125, IAC Caiapó and IAC Runner 886 with runner growth habit, and soybean genotype BR 16 as a susceptible control. The biological parameters: leaf consumption, larval (4º instar) and pupal (24h old) weight, larval and pupal development time and adult longevity were evaluated at laboratory conditions. The genotypes IAC 147 and IAC Runner 886 were resistant to A. gemmatalis in both cluster tests, grouping apart from most of the other genotypes. Both dendrogram and K-means methods provided satisfactory biological explanation, and they can be complementary used together with Principal Component and vice-versa. These results suggest that cluster analyses may be an important statistical tool in the selection of host plant resistance.

Produtividade de genótipos de soja sob infestação da lagarta-da-soja e de percevejos / Yield of soybean genotypes under infestation of the velvetbean caterpillar and stink bugs

Three soybean experiments, one for each maturation group (early, semi-early, and medium), were installed in the field in Assis, State of São Paulo, during the 2003/2004 growing season to evaluate damage caused by Anticarsia gemmatalis (Hubn.) and by the soybean stink bug complex, Euschistus heros (F.), Piezodorus guildinii (West.), and Nezara viridula (L.). The experiments were installed again in 2004/2005, with the exception of the early cycle group. Defoliation caused by A. gemmatalis was evaluated by the percentage estimate of leaf area cut in the first year only, due to low caterpillar infestations in 2004/2005. All three stink bug species were present in both growing seasons. In 2003/2004, E. heros was predominant over the other two; in the following year, all three species occurred in similar numbers. The productivity criterion was adopted to evaluate stink bug damage. Based on both growing seasons and mainly considering productivity, a few lines could be selected within each maturation group for new field studies or for hybridizations in breeding programs. Among the early germplasm varieties, lines IAC 98-4540, IAC 98-4576, and IAC 98-3123 can be highlighted as promising; the latter also showed little defoliation by A. gemmatalis; in the semi-early group, IAC 98-4017, IAC 98-2663, and IAC 98-4250 were prominent, with steady productivity in both years; in the medium group, IAC 98-4136, the most productive, as well as IAC 98-4140 and IAC 98-4133, all with little defoliation, can be pointed out as promising.

Resistência de genótipos de abobrinha a Bemisia tabaci (Genn. ) biótipo B (Hemiptera: Aleyrodidae) / Resistance of squash genotypes to Bemisia tabaci (Genn. ) biotype B (Hemiptera: Aleyrodidae)

Ensaios foram realizados no campo visando avaliar a atratividade e a não-preferência para oviposição da mosca-branca Bemisia tabaci (Genn.) biótipo B por genótipos de abobrinha (Cucurbita pepo) e também observar a sensibilidade dos genótipos (Novita, Sandy, Caserta Cac Melhorada, Novita Plus, Samira, Bianca, AF-2858 and Caserta TS) ao sintoma de prateamento foliar. O genótipo Sandy foi o menos atrativo à mosca-branca, enquanto que Novita Plus, AF-2858 e Samira foram os mais atrativos. O genótipo Caserta Cac Melhorada foi o menos ovipositado. Os genótipos Sandy e AF-2858 foram os mais produtivos, com as maiores médias de frutos produzidos. Os genótipos Sandy e Caserta Cac Melhorada apresentaram os menores índices de sintoma de prateamento foliar.

Field assays were performed to evaluate the attractiveness and the non-preference of whitefly Bemisia tabaci (Genn.) biotype B for oviposition on squash genotypes (Cucurbita pepo) and to observe the susceptibility of genotypes (Novita, Sandy, Caserta Cac Melhorada, Novita Plus, Samira, Bianca, AF-2858 and Caserta TS) to silverleaf symptoms. The Sandy genotype was the least attractive to whitefly, while Novita Plus, AF-2858 and Samira were the most attractive. The Caserta Cac Melhorada genotype was the least preferred for oviposition. The Sandy and AF-2858 genotypes were the most productive, with the highest mean of fruits produced. The lowest silverleaf symptoms index was observed for the Sandy and Caserta Cac Melhorada genotypes.

Resistência de genótipos de milho para cultivo em várzeas subtropicais à lagarta-do-cartucho Spodoptera frugiperda / Resistance of corn genotypes for subtropical lowland cropping to fall armyworm Spodoptera frugiperda

Spodoptera frugiperda é uma das pragas com elevado potencial para causar perdas econômicas na cultura do milho, no ecossistema de várzeas subtropicais. Com o objetivo de identificar fontes de resistência, foi avaliado, em laboratório, o desenvolvimento de S. frugiperda em nove genótipos de milho. Cem lagartas recém-eclodidas foram individualizadas em tubos de vidro, contendo porções de folhas de milho, mantidos à temperatura de 25±1°C, umidade relativa de 70±10 por cento e fotofase de 14h. Avaliaram-se a duração e a viabilidade das fases de larva e pupa, o peso de larvas e de pupas e a mortalidade larval. Dentre os genótipos avaliados, destacaram-se o BRS Missões-B e o BR 111 VI Sel. Dent C, os quais afetaram, respectivamente, o desenvolvimento da fase de larva e de pupa.

Spodoptera frugiperda is the most important pest of the corn culture, causing high leaf losses. With intention to identify possible resistance sources, it was evaluated the effect of nine maize genotypes on the development of S. frugiperda in laboratory. One hundred newly-hatched larvae were individualized in glass tubes containing leaves, maintained under temperature of 25±1°C, relative humidity of 70±10 percent and photophase of 14h. Larval and pupal developmental time, survivorship and weight and larval mortality at 16 days were evaluated. It was observed that the genotypes BRS Missões-B and BR 111 VI Sel. Dent C affected the larval and pupal development, respectively.

Preferência de Bemisia tabaci biótipo B em linhagens mutantes de algodoeiro / Bemisia tabaci biotype B preference in mutant cotton lines

Os efeitos de caracteres mutantes morfológicos do algodoeiro (Gossypium hirsutum L. r. latifolium Hutch.): folha okra, bráctea frego e planta vermelha, em relação à resistência à mosca-branca (Bemisia tabaci biótipo B Hemiptera: Aleyrodidae), foram avaliados em experimentos com ou sem chance de escolha. Os experimentos foram conduzidos em casa-de-vegetação, no delineamento de blocos ao acaso, em fatorial 23 + 1, com quatro repetições. O mutante com a característica planta vermelha foi menos atrativo e menos preferido para oviposição, em relação à planta verde, em ambos os ensaios, com ou sem escolha. Não houve preferência quanto à forma da folha e ao tipo de bráctea.

The effects of cotton lines (Gossypium hirsutum L. r. latifolium Hutch.) with mutants morphologic characteristics: okra leaf, frego bract and red plant in relation to host plant resistance to whitefly (Bemisia tabaci bioyipe B Hemiptera: Aleyrodidae), were evaluated in choice or no choice assays. The assays were carried out in the greenhouse conditions, according to a completely randomized block design, in a 23 + 1 in a factorial arrangement with four replications. The mutant with red plant characteristic was less attractive and less preferred for oviposition than the normal green plant does, in both, whit or without choice tests. It did not have preference in relation to the form of the leaf and bract type.

Relação predador: presa de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) para o controle do pulgão-verde em genótipos de sorgo / Predator: prey ratios of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) for the control of greenbug in sorghum genotypes

O uso da resistência de plantas associado a agentes de controle biológico pode ser uma alternativa viável no controle de Schizaphis graminum (Rondani) em sorgo. Objetivou-se estudar diferentes relações predador:presa em genótipos de sorgo resistente (TX 430 x GR 111), moderadamente resistente (GB 3B) e suscetível (BR 007B) para o controle do pulgão-verde por Chrysoperla externa (Hagen). Para isso foram realizadas, em condições de casa-de-vegetação, liberações do crisopídeo nas relações predador:presa de 1:5; 1:10; 1:25 e 1:50. O genótipo TX 430 x GR 111 foi o mais eficiente no controle do pulgão-verde, S. graminum, assim como as relações predador:presa de 1:5 e de 1:10 nos três genótipos. A interação resistência de plantas e controle biológico foi positiva e permitiu controle acima de 80 por cento nas relações predador:presa de 1:5 e 1:10 no material resistente TX 430 x GR 111; no genótipo GB 3B o melhor controle foi obtido com 1 predador: 5 presas.

The use of host plant resistance associated with biocontrol agents may be a viable alternative to Schizaphis graminum (Rondani) control in sorghum. This work aimed to study different predator:prey ratios on genotype resistant (TX 430 x GR 111), moderately resistant (GB 3B) and susceptible (BR 007B) for the aphid control by the predator Chrysoperla externa (Hagen). Thus, the lacewings were released at the predator:prey ratios of 1:5; 1:10; 1:25 and 1:50 under greenhouse conditions. The genotype TX x GR 111 was the most efficient to control S. graminum, as well the 1:5 and 1:10 predator: prey ratios on the three genotypes. The interaction between plant resistance and biological control with C. externa was positive and permitted a control over 80 percent at the predator:prey ratios of 1:5 and 1:10; on the GB 3B genotype the best control was at the 1:5 predator:prey ratio.