Resistance of cotton genotypes with different leaf colour and trichome density to Bemisia tabaci biotype B

摘要: AbstractThe silverleaf whitefly (SLW), Bemisia tabaci biotype B, is considered oneof the most serious pests in cotton worldwide. Its control based on theuse of pesticides, which are well-known for their harmful effects non-target organisms and environment. Here, we examined resistance ofseveral genotypes terms antixenosis antibiosis againstSLW. We also investigated mechanisms involvedin against SLW by correlating with leaf trichome density andleaf colour parameters. In choice tests, selected resistant geno-types, Gossypium hirsutum palmeri, Aubum 56-7, G. morrilli,Moco, Nu-16 (B2 B3 B6)- 78/658, Paymaster 53-816 ‘IAC 23’, basedon oviposition host preference. No-choice tests these geno-types confirmed effect SLW; however, no antibiosisresistance was detected developmental period adultemergence rate. found preference positively cor-related abaxial surface, while adult hostpreference mostly explained high levels green intensity ofadaxial surface. Nevertheless, both preferencewere negatively correlated lightness level adaxial surface.Probably, underlying mechanism morethan just two parameters, but our study will contribute to selectingresistant helps understand mechanismsinvolved SLW. To best knowledge, this isthe first work showing that parameters related toresistance SLW.IntroductionMany crops tropical subtropical regions areseverely damaged tabaci(Genn.) (Hemiptera: Aleyrodidae). past,whiteflies were a secondary pest, asinfestations have caused yield losses due directdamage transmission more than 200 plantviruses, currently regarded one mostimportant field greenhouse cropsworldwide (Brown 1994; De Barro et al. 2011; Navas-Castillo 2011).In Brazil, B. recorded 1923(Bondar 1928) A populations likelythe only ones present until 1990s. Invasion bybiotype B (silverleaf or SLW) occurred theearly 1990s S~ao Paulo state. This whiteflybiotype likely originated from imported plant material(Lourenc ~ao Nagai 1994) rapidly spread acrossthe country. Recent molecular studies showed thatbiotype predominant many differentparts such as cotton, potato, tomato, pump-kin, cabbage soya beans (Fontes 2010;Rocha Valle 2011). Even though