No-choice ovipositional nonpreference of Bemisia tabaci (Gennadius) B biotype on tomato genotypes

Abstract

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...

Biological aspects of the beetle Delphastus davidsoni fed with whitefly eggs laid on tomato genotypes

“…On the other hand, the high density of type V nonglandular trichomes did not interfere in the larvae development time; low larval mortality was observed on the NAV1062 genotype (28.8 %). In an experiment including 18 tomato genotypes, Oriani et al (2011a) observed that NAV1062 (S. pimpinellifolium) presented the second greatest density of nonglandular trichomes (59.5 mm −2 ), lower only in number recorded for LA1963 genotype (S. chilense) (63.7 mm −2 ).…”

“…However, glandular trichomes release exudates that are able to capture whiteflies (Muigai et al, 2002;Oriani and Vendramim, 2010;Oriani et al, 2011a). Furthermore, glandular trichomes also captured a great number of first-instar of D. davidsoni, which were trapped by the exudates released by these trichomes.…”

“…Four tomato genotypes were chosen based on differences in the densities and types of trichomes, levels of antixenosis for oviposition (Oriani and Vendramim, 2010;Oriani et al, 2011a) and levels of feeding non-preference and/or antibiosis-based resistance (Oriani et al, 2011b) to B. tabaci B biotype. The chosen genotypes were: i) NAV1062 (S. pimpinellifolium = L. pimpinellifolium) -low degree of antixenosis for oviposition, low degree of feeding non-preference and/or antibiosis, and high density of type V non-glandular trichomes; ii) LA1335 (S. pimpinellifolium) -low degree of antixenosis for oviposition, high degree of feeding non-preference and/ or antibiosis, and low density of type V non-glandular trichomes; iii) PI134418 (S. habrochaites f. glabratum = L. hirsutum f. glabratum) -high degree of antixenosis for oviposition, low degree of feeding non-preference and/or antibiosis, and high density of type IV glandular trichomes; and iv) IAC294 (S. habrochaites f. glabratum) -low degree of antixenosis for oviposition, low degree of feeding non-preference and/or antibiosis, and medium density of type IV glandular trichomes.…”

“…In Solanum lycopersicum (=Lycopersicon esculentum Mill) (Peralta et al, 2006), type V trichome density is positively related to B. tabaci oviposition (Heinz and Zalom, 1995;Snyder et al, 1998), and type IV and VI glandular trichomes cause antixenosis for oviposition (Muigai et al, 2002;Oriani and Vendramim, 2010;Oriani et al, 2011a). Trichomes may also influence the searching behavior of natural predators (Hare, 1992;Guershon and Gerling, 2006), and predator efficiency may be adversely affected due to an increase in searching time for the prey (Botrell et al, 1998).…”

Levels of Plant Resistance in Chillies Capsicum spp against Whitefly, Bemisia tabaci

“…In the present study, the adults showed no longdistance flights and they just remained consistent within the experimental arena (glass chimney). Also, Oriani et al, (2011) from their study suggested that, high levels of antixenosis for oviposition was related to type IV glandular trichomes of tomato accessions against B. tabaci. In Capsicum spp.…”