-Brazil is one of the world's largest tomato producer, but considerable part of the production is lost due to the attack of Bemisia tabaci (Genn.) B biotype. Resistant germoplasm plants can be an important method for B. tabaci control in integrated pest management approaches. The attractiveness and ovipositional preference of B. tabaci for 17 tomato genotypes were evaluated in a free-choice test. Trials were set up in a randomized block design with ten replicates. Each replicate (one tomato plant per pot) was placed in a cage (80 x 50 x 50 cm) and infested with 1,000 adults during four days. Linear correlation tests were applied between the number of insects and eggs and number of trichomes in each tomato genotype. LA716, LA444-1 and PI134418 genotypes were the least attractive, while the 'Santa Clara' was the most attractive; PI134417 trapped the largest number of adults. LA716 genotype (4.1 eggs/leafl et and 2.1 cm 2 /eggs per leafl et) was the least preferred for whitefl y oviposition; NAV1062, 'Fanny', LA1335, 'Santa Clara' and IAC294 were the most preferred genotypes. The glandular trichomes density was negatively correlated with whitefl y's attractiveness and oviposition per leafl et and per leaf, and positively with the number of trapped insects. The non-glandular trichomes density was negatively correlated with the number of trapped insects and positively with whitefl y's oviposition per cm 2 /leafl et and per cm 2 /leaf. LA716 had high antixenosis level (ovipositional nonpreference) toward B. tabaci B biotype related with type IV glandular trichome.

The biology of Bemisia tabaci biotype B (Genn.) on bean (Phaseolus vulgaris L.) genotypes containing arcelin in the seeds was evaluated. Also, biochemical screening of seeds and leaves material of these genotypes were carried out in order to verify if traces of arcelin could be found in its leaves. The tests were conducted under greenhouse conditions, in the dry and wet seasons, with the following genotypes: ARC 3s, ARC 5s (wild genotypes containing arcelin in the seeds); ARC 1, ARC 2, ARC 3, ARC 4 (near isogenic lines containing arcelin in the seeds - EMBRAPA) and Porrillo 70, Bolinha, IAPAR MD 808 (commercial genotypes without arcelin). The wild genotypes, ARC 3s and ARC 5s, showed high levels of antibiosis resistance type, mainly for ARC 5s which presented the highest nymphs mortality rates, approximately 90%. Also, the longest development time for nymphs fed on ARC 5s genotype suggest antibiosis and/or feeding nonpreference resistance type. The wild genotype resistance is not related with arcelin presence in the seeds, since no trace of this protein was found in its leaves.

Brazil is one of the main tomato (Solanum lycopersicum) producers worldwide. Nevertheless, considerable part of the production is lost due to Bemisia tabaci (Genn.) B biotype attacks. Resistant plants can be an important method for controlling this pest in an integrated pest management. Tests for evaluating some biological aspects of B. tabaci were carried out on 18 tomato genotypes, in controlled laboratory greenhouse conditions. Thirty-day-old plants placed in plastic cages were infested with 20 whitefly pairs each, for 24 h. The development of at least 30 eggs in three leaflets per plant (repetition) was observed until adult emergence. The development period of insects grown in LA1335, PI365928 and LA722 genotypes took three days longer when compared to the ones grown in PI134418 (20.3 days). The highest mortality rate of whitefly nymphs occurred in PI365928, LA1335 and LA722 genotypes (63.8, 54.5 and 53.3%, respectively), and the smallest ones in IAC294 and IAC68F-22-2 genotypes (4.9 e 6.2%, respectively). LA1335, PI365928 and LA722 genotypes presented moderate feeding nonpreference and/or antibiosis-based resistance to B. tabaci B biotype.

Brazil is one of the main tomato producers worldwide. Nevertheless, 40 to 70% of the production is lost due to Bemisia tabaci (Gennadius) B biotype attacks. Resistant plant germplasm can be an important method for controlling this pest in an integrated pest management program. This research aimed to evaluate the no-choice ovipositional preference of B. tabaci B biotype on 18 tomato genotypes with different densities and types of trichomes testing two screening techniques and to determine the influence of trichomes on whitefly ovipositional preference. Two methods of confinement experiments were used. Leaflets detached from the upper third part of the tomato plants (first experiment) and 30-day-old plants (second experiment) were infested with whiteflies during 24 h. For the first experiment, simple linear correlation tests between the number of insects and eggs, and number of trichomes in the tomato genotypes were carried out. The first technique was better than the second one, as it was easier to carry out and the evaluation demanded less time and as well as was effective to discriminate the resistance level of the evaluated genotypes. Glandular trichomes had a negative correlation with attracted adults and number of eggs deposited, and a positive correlation with number of trapped insects. Negative correlations were observed between number of nonglandular trichomes and trapped insects, and also between total number of trichomes and attracted and trapped insects. Positive correlations were observed between number of total trichomes and eggs cm -2 and nonglandular trichomes and number of eggs. Both confinement methods efficiently discriminated whitefly oviposition among genotypes, especially the resistant ones. High levels of antixenosis for oviposition related to type IV glandular trichomes were exhibited by genotypes LA716, PI134417 and PI134418. The high level of ovipositional preference by B. tabaci for genotypes LA1963 and NAV1062 was related to a high density of type V nonglandular trichomes. Key words: Solanum lycopersicum, plant resistance, whitefly, antixenosis, trichomes Não-preferência para oviposição de Bemisia tabaci (Gennadius) biótipo B em genótipos de tomateiro em teste sem chance de escolha RESUMO: O Brasil é um dos maiores produtores mundiais de tomate, porém grande parte da produção é perdida devido ao ataque de Bemisia tabaci (Gennadius) biótipo B. Entre as táticas de controle dessa praga num manejo integrado de pragas, pode-se relacionar a resistência de plantas. Avaliou-se a preferência para oviposição de B. tabaci biótipo B por 18 genótipos de tomateiro com diferentes densidades e tipos de tricomas utilizando-se dois métodos e estudou-se a influência dos tricomas nesta preferência, utilizando-se dois métodos para os experimentos de confinamento. Folíolos seccionados do terço superior dos tomateiros (primeiro método) e plantas com 30 dias de idade (segundo método) foram infestados com moscas-brancas durante 24 h. Para o primeiro experimento, foram realizados testes de correlação l...

-The oviposition preference (free-choice tests) of Bemisia tabaci (Genn.) Biotype B for 20 bean genotypes was tested. The genotypes were divided into two plots and set up in a block-randomized design with 20 replications. New expanded bean leaves were sectioned and placed in glass tubes containing distilled water and disposed in acrylic cages containing approximately 500 insects. After 24h, the total number of eggs laid on the abaxial surface of leaves and the density of straight and hooked trichomes in two areas of 4.9 mm 2 on the abaxial surface were counted. The leaf area was measured as well as the maximum and minimum length of hooked and straight trichomes, which were classified in short, medium or long. No significant correlation was found between the number of eggs and the density of total trichomes (straight + hooked) or between hooked or straight trichomes. Significant correlation was detected between the number of eggs and long straight trichomes type A 1 (r = 2.85) and short hooked trichomes type B 3 (r = -2.44). In this way, the ovipositional preference of B. tabaci for Bolinha genotype (4.8 eggs/cm 2 ) in a free-choice test could be associated to the larger number of long straight trichomes type A 1 (31.7 trichomes/4.9 mm 2 ) on its leaves surface. In addition, the whitefly ovipositional nonpreference for G13028 wild genotype (1.1 eggs/cm 2 ) could be related with the numerous short hooked trichomes type B 3 (64.1 trichomes/4.9 mm 2 ) on its leaves surface.KEY WORDS: Insecta, Phaseolus vulgaris, whitefly, antixenosis RESUMO -Foi testada a preferência para oviposição (com chance de escolha) de Bemisia tabaci (Genn.) biótipo B em 20 genótipos de feijoeiro. Os materiais foram divididos em dois lotes, utilizando-se em cada um deles delineamento em blocos ao acaso, com 20 repetições. Folhas recém-expandidas de cada genótipo foram mantidas em tubos de vidro contendo água destilada, colocadas em uma gaiola acrílica, onde foram liberados cerca de 500 insetos. Após 24h, contou-se o número total de ovos na superfície abaxial e o número de tricomas aciculares e unciformes em duas áreas de 4,9 mm 2 da superfície abaxial. Mediu-se também a área foliar dos feijoeiros e o comprimento máximo e mínimo dos tricomas, que foram classificados em curto, médio ou longo. Não foram constatadas correlações significativas entre o número de ovos e a densidade de tricomas total e de tricomas aciculares e unciformes. Foram observadas correlações significativas entre o número de ovos e a densidade de tricomas aciculares longos tipo A 1 (r = 2,85) e a densidade de tricomas unciformes curtos tipo B 3 (r = -2,44). Assim, pode-se inferir que a preferência para oviposição da mosca-branca pela cultivar Bolinha (4,8 ovos/cm 2 ) pode estar relacionada ao grande número de tricomas aciculares longos neste material tipo A 1 (31,7 tricomas/ 4,9 mm 2 ). O contrário pode ser considerado quanto ao genótipo menos preferido, G13028 (1,1 ovos/ cm 2 ), que possui principalmente tricomas unciformes curtos tipo B 3 (64,1 tricomas/4,9 mm 2 ) ...

An. Soc. Entomol. Brasil 29 (3): 565-572 (2000) Preferência para Oviposição de Bemisia tabaci (Genn.) Biótipo B(Homoptera: Aleyrodidae) por Genótipos de Feijoeiros Portadores de Arcelina nas Sementes RESUMO -Genótipos de feijoeiro (P. vulgaris) que contêm arcelina em suas sementes foram avaliados quanto à preferência para oviposição de Bemisia tabaci biótipo B (Homoptera: Aleyrodidae). Os testes foram conduzidos em condições de estufa, nas épocas "das águas" e "da seca", em dois anos consecutivos, com os seguintes genótipos: ARC 3s, ARC 5s (genótipos selvagens portadores de arcelina); ARC 1, ARC 2, ARC 3, ARC 4 (linhagens quase-isogênicas portadoras de arcelina -EMBRAPA), Porrillo 70, Bolinha e IAPAR MD 808 (cultivares sem arcelina). Nos ensaios de preferência para oviposição, em teste com e sem chance de escolha, observou-se que os genótipos Bolinha e Porrillo 70 foram os mais preferidos para oviposição pelo inseto. A suscetibilidade do genótipo Bolinha pode estar relacionada com o grande número de tricomas aciculares presentes em suas folhas. Os genótipos selvagens, ARC 5s e ARC 3s, apresentaram resistência do tipo não-preferência para oviposição. Esta resistência não está relacionada com a arcelina, uma vez que os genótipos melhorados também contêm arcelina em suas sementes e não mostraram-se resistentes a esse biótipo de B. tabaci.ABSTRACT -The oviposition preference of Bemisia tabaci biotype B (Homoptera: Aleyrodidae) for bean (Phaseolus vulgaris L.) genotypes containing arcelin in the seeds was evaluated. The tests were carried out under greenhouse conditions, in the dry and wet seasons, with the following genotypes: ARC 3s, ARC 5s (wild genotypes containing arcelin in the seeds); ARC 1, ARC 2, ARC 3, ARC 4 (near isogenic lines containing arcelin in the seeds -EMBRAPA) and Porrillo 70, Bolinha, IAPAR MD 808 (commercial genotypes without arcelin). In the free choice and no-choice oviposition tests, Bolinha and

-Whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germoplasm plants can be an important method for controlling this pest. The oviposition preference of Bemisia tabaci biotype B for 20 bean genotypes was tested. In a free-choice test, the genotypes were divided into two plots of 10 replicates. The bean plant pots were set up in a randomized design in a cage (80 x 50 x 50 cm) covered by nylon netting and infested with 1.000 adults during four days. No-choice test was carried out with 20 replicates where one newly expanded leaflet from bred genotypes and cultivars or one leaf from wild genotypes, was placed in a cage infested by 25 pairs of whiteflies during 48h. In freechoice tests, the genotypes G13028, Arc 5s, Arc 1s, G11056, Arc 3s presented the smaller oviposition and preference index, varying from -91.9 to -78.6, while Arc 1 (+33.0) had greater index. In no-choice tests, smaller number of eggs/leaflet were observed in genotypes G13028 (28.2), Arc 3s (37.6) and G23425E (39.0), whereas the most preferred had 105.0 eggs/leaflet (Bolinha). The wild genotype G13028 was highly resistant (oviposition nonpreference) toward B. tabaci B biotype. The wild genotypes Arc 3s, Arc 5s and G11056 were also resistant. The Bolinha, Arc 1 and Arc 4 genotypes were highly susceptible to whitefly oviposition.

-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% 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.