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

Abstract

The silverleaf whitefly (SLW), Bemisia tabaci biotype B, is considered one of the most serious pests in cotton worldwide. Its control is based on the use of pesticides, which are well-known for their harmful effects on nontarget organisms and the environment. Here, we examined resistance of several cotton genotypes in terms of antixenosis and antibiosis against SLW. We also investigated the mechanisms of cotton genotypes involved in antixenosis against SLW by correlating with leaf trichome density and leaf colour parameters. In choice tests, we selected resistant cotton genotypes, Gossypium hirsutum palmeri, Aubum 56-7, G. hirsutum morrilli, Moc o, Nu-16 (B2 B3 B6)-78/658, Paymaster 53-816 and 'IAC 23', based on SLW oviposition and host preference. No-choice tests with these genotypes confirmed antixenosis effect on SLW; however, no antibiosis resistance was detected in terms of developmental period and adult emergence rate. We found SLW oviposition preference was positively correlated with trichome density in the abaxial leaf surface, while adult host preference was mostly explained by high levels of green intensity of adaxial surface. Nevertheless, both SLW oviposition and host preference were negatively correlated with the lightness level of adaxial leaf surface. Probably, the underlying mechanism of cotton resistance is based on more than just these two parameters, but our study will contribute to selecting resistant cotton genotypes and helps to understand the mechanisms involved in cotton resistance against SLW. To our best knowledge, this is the first work showing that cotton leaf colour parameters are related to resistance against SLW.

Resistance of Manihot esculenta and its intraspecific hybrids to the whitefly Aleurothrixus aepim (Hemiptera: Aleyrodidae)

“…Some studies have shown that there is not always a correlation between the number of trichomes and the number of eggs oviposited by whiteflies. Prado et al (2015), who evaluated Bemisia tabaci infestation on a cotton crop, observed a negative correlation; however, for the same crop, there have also been cases where no correlation was found between these two variables (Boiça Jr. et al, 2007;Torres et al, 2007). Although there were differences for the density of trichomes on the leaves of the Manihot genotypes, this did not influence the number of eggs oviposited by A. aepim (the Spearman's correlation coefficient was not significant, at 5% probability, by the t test = -0,1515).…”

“…Although Manihot genotypes showed significant differences in the present study, the preference of A. aepim was not related to leaf color because there was no correlation between oviposition preference and intensity of the green color of the leaves (a) (Spearman's correlation coefficient not significant at 5% probability by the t test = -0.2025). However, in a study with B. tabaci on cotton, the whitefly preferred to lay eggs on the genotypes that had leaves with a more intense green color (a) (Prado et al, 2015). Some studies have also shown that whiteflies tend to be attracted to yellow (Moreau & Isman, 2011;Shimoda & Honda, 2013).…”

Silverleaf whitefly-resistant common beans: an investigation of antibiosis and/or antixenosis

“…Based on the available literature, the duration of the egg to adult period varies between bean genotypes, and there are reports of periods between 16.20 and 41.00 days (Oriani and Lara 2000;Torres et al 2012). Some references reported a large variation in the development period of the whitefly on cowpea genotypes (Cruz et al 2014), cabbage (Villas Bôas et al 1997), cotton (Prado et al 2015), soybean (Cruz and Baldin 2016), tomato (Baldin et al 2005), squash varieties (Baldin and Benduzzi 2010), melon (Baldin et al 2012) and, more recently, peppers, where a duration of 30.25 days was observed (Pantoja et al 2018), similar to the present study.…”

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

“…A randomized-block design was used, with the four treatments and 15 blocks. Soybean seedlings, cultivated and infested with about 600 non-viruliferous B. tabaci MEAM1 adults/plant as in Prado et al (2016), served as a source for whiteflies in this test. A potted soybean seedling was positioned in the centre of each block and equidistant (50 cm) from the potato plants.…”