Resistência de clones de batata a Bemisia tabaci biótipo B

Abstract

Palavras-chave: Solanum tuberosum, Aleyrodidae, mosca-branca, resistência de plantas a insetos. ABSTRACT Resistance of potato clones to Bemisia tabaci biotype BThe resistance of 30 potato genotypes to B. tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) was evaluated in three greenhouse experiments. In the first experiment we evaluated the attractiveness, the preference for oviposition and the trichome density in a freechoice test in randomized blocks design with 30 treatments and three replications. In other experiment, no-choice preference for oviposition was evaluated (randomized blocks, nine treatments and five replications). The whitefly egg-adult cycle was monitored using a statistical design in randomized blocks with five replications. In the free-choice test, the genotypes NYL 235-4 and MAC 2 were the most attractive to adults, whereas HPC 5B and BAP 82 presented the lowest number of adults. The genotypes HPC 6R, BACH 4, clone APTA 2135, HPC 9B, BAP 82, 'Baraka' and HPC 5B presented the lowest number of eggs. Clone NYL 235-4 had the greatest number of simple (ST) and glandular (GT) trichomes, whereas clone CH 2 had the lowest number of ST, and HPC 5B, 'Radosa', 'Cupido', 'Caesar', 'Saginaw Gold', BACH 3 and HPC 1B of GT. There was significant correlation between adult attractiveness and oviposition preference. In the no-choice test, only the genotypes BACH 4, HPC 9B, 'Baraka and 'Achat' remained resistant. Consequently, for these four genotypes non-preference is the oviposition resistance mechanism. The egg adult cycle varied from 34.4 to 36.6 days. For the adult emergence, genotypes BAP 82, 'Baraka' and BACH 4 showed the lowest number of adults emerged, suggesting the presence of antibiosis. Genotypes BAP82, 'Baraka' and BACH 4 were resistant to B. tabaci biotype B.

Infection by the semi-persistently transmitted Tomato chlorosis virus alters the biology and behaviour of Bemisia tabaci on two potato clones

“…Our study showed that adults of B. tabaci MEAM1 preferred ToCV-infected potato plants of both clones as a host relative to mock-inoculated plants of Bach-4, but not compared with mock-inoculated plants of ‘Agata’. This difference in the whitefly response to mock-inoculated plants may be due to the natural susceptibility of ‘Agata’ to B. tabaci MEAM1 compared with Bach-4 (Rocha et al ., 2012). Even though adults of B. tabaci MEAM1 did not discriminate ToCV-infected plants from mock-inoculated plants of ‘Agata’ clone, whitefly adults alighted and settled on ToCV-infected plants of both clones equally, indicating that the virus induces a phenotype that optimizes its acquisition by B. tabaci MEAM1 in both clones.…”

“…‘Agata’ is a Dutch clone of the original cross between ‘Bohm’ and ‘Sirco’, and Bach-4 is a clone from the cross between ‘Bannock Russet’ and Solanum chacoense subsp. muelleri (Hawkes & Hjerting) (Rocha et al ., 2012). Potato tubers were grown in 3 litres-capacity pots (one tuber/pot) containing a mixture of soil and organic matter (Raij et al ., 1997).…”

“…Here, we investigated whether the behaviour and biology of B. tabaci MEAM1 increases the likelihood of ToCV acquisition, transmission and spread in potato. We selected two potato clones, one susceptible (‘Agata’) and the other moderately resistant (Bach-4) to B. tabaci MEAM1 (Silva et al ., 2008; Rocha et al ., 2012). We specifically tested the following hypotheses for both clones: ( i ) whiteflies orient preferentially to ToCV-infected potato clones compared with non-infected clones; ( ii ) whitefly females prefer to oviposit on ToCV-infected potato clones compared with non-infected clones; ( iii ) whiteflies feeding on the ToCV-infected clone migrate preferentially to the non-infected clone, optimizing the spread of the virus; ( iv ) the life cycle of whiteflies that have been fed on the ToCV-infected potato plants is shorter compared with individuals that have been fed on the non-infected plants; and ( v ) virus manipulation of the plant for enhancing transmission is more pronounced in the susceptible than in the moderately resistant clone, as proposed by Mauck (2016).…”

Manejo de pragas no controle de doenças no cultivo de hortícolas

“…Rocha et al (2012), avaliaram a resistência de 30 genótipos de batata a B. tabaci biótipo B em casa de vegetação, por meio de três experimentos, verificando a atratividade para adultos, a preferência para oviposição e a densidade de tricomas simples e glandulares., obtendo como resultados os clones "Baraka" e BACH 4 destacando-se como os mais resistentes ao inseto na cultura. Nascimento et al (2013), avaliaram a atratividade de cultivares de feijão-caupi para alimentação da mosca-branca Bemisia tabaci biótipo B em condições de casa de vegetação, sob infestação natural e livre chance de escolha, testou 20 cultivares do feijão-caupi, constatando que das variedades estudadas a Corujinha e Capela, que não diferiram entre si, são as mais atrativas, o que indica que para o manejo da cultura, plantas resistentes a praga devem ser utilizadas.…”