Pest Management Science (2020) 76, 464-471

Elaine S.S. Goiana, Nivia S. Dias-Pini, Celli R. Muniz, Arlete A. Soares, James C. Alves, Francisco C. Vidal-Neto and Cherre S. Bezerra Da Silva (2020)
Dwarf-cashew resistance to whitefly (Aleurodicus cocois) linked to morphological and histochemical characteristics of leaves
Pest Management Science 76 (2), 464-471
Abstract:
BACKGROUND
The cashew whitefly (CW), Aleurodicus cocois, is an important pest of cashew in Brazil. The use of resistant plants may be an effective strategy for the control of this pest. In a preliminary assay, we found that dwarf-cashew clones show different levels of resistance to CW. Here, we hypothesized that such resistance is associated with morphological characteristics of cashew leaves and their content of phenolic compounds.
RESULTS
We determined (i) the attractiveness and suitability for oviposition of five dwarf-cashew clones towards CW, (ii) the leaf morphology and chemistry of those clones, and (iii) the relationship between leaf characteristics and resistance to CW. In greenhouse multiple-choice assays, PRO143/7 and CCP76 showed, respectively, the lowest and highest counts of both CW adults and eggs. Scanning electron microscopy (SEM) analysis revealed that PRO143/7 and EMBRAPA51 have, respectively, the highest and lowest numbers of leaf glandular trichomes. We found a negative correlation between number of trichomes in the abaxial surface of cashew leaves and CW oviposition. In addition, confocal microscopy analysis and histochemical tests with ferrous sulfate indicated a higher accumulation of phenolic compounds in the resistant clone PRO143/7 relative to the other clones. Dwarf-cashew clones did not significantly differ based on the number of leaf epicuticular striations, and the thickness of both leaf lamina and the epidermal layer.
CONCLUSION
The resistance of dwarf-cashew plants to CW is associated with an elevated number of trichomes and accumulation of high levels of phenolics in leaves. Additionally, the contribution of epicuticular striation density and thickness of leaf lamina/epidermal layer are insignificant.
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Link to article at publishers website
Database assignments for author(s): Nivia da Silva Dias-Pini

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aleurodicus cocois	Cashew (Anacardium occidentale)