Uso de silício como indutor de resistência em batata a Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Abstract

-The aphid Myzus persicae (Sulzer) is an important pest of potato and causes direct harm, due to the quantity of sap extracted and for being vector of important phytovirus. This work was carried out to evaluate the action of silicon as a resistance inducer of potato to M. persicae. Four treatments were tried: foliar fertilization with silicon acid at 1%; soil fertilization with 250 ml silicic acid solution at 1%; foliar fertilization with silicon acid at 1% + soil fertilization with 250 ml silicic acid solution at 1%; and a control. The treatments were applied thirty days after the explants emergence. Fifteen days after the application of the treatments, feeding preference and some biological aspects of the aphids were evaluated. After, the content of tannins and lignin present in the leaves and the activity of the enzymes peroxidase and phenylalanine ammonia-lyase were also determined. The silicon fertilization did not affect the preference of the aphids; however it reduced fecundity and the rate of population growth of the insects. The lignin percentage increased in the leaves of plants fertilized with silicon via soil and/or foliar and the percentage of tannins increased only in the leaves fertilized via soil plus foliar. The silicon acted as a resistance inducer to M. persicae in potato.KEY WORDS: Silicic acid, aphid, induced resistance, IPM RESUMO -O pulgão Myzus persicae (Sulzer) é uma importante praga da batateira, causando danos diretos pela quantidade de seiva extraída e por ser vetor de importantes fi tovírus. Este trabalho foi realizado para verifi car a atuação do silício como indutor de resistência em batata a M. persicae. Foram utilizados quatro tratamentos: adubação foliar com solução de ácido silícico a 1%; adubação via solo com 250 ml de solução de ácido silícico a 1%; adubação foliar com solução de ácido silício a 1% + adubação via solo com 250 ml de solução de ácido silícico a 1%1; e a testemunha. Os tratamentos foram aplicados trinta dias após a emergência das brotações. Após quinze dias da aplicação dos tratamentos avaliou-se a preferência e alguns aspectos biológicos do pulgão. Posteriormente foi feita a quantifi cação do teor de taninos e de lignina presentes nas folhas e a determinação das atividades das enzimas peroxidase e fenilalanina amônia-liase. A adubação silicatada não afetou a preferência dos pulgões, porém diminuiu a fecundidade e a taxa de crescimento populacional dos insetos. A percentagem de lignina aumentou nas folhas das plantas adubadas com silício via solo e/ou foliar e a porcentagem de taninos aumentou apenas nas folhas das plantas adubadas via solo + foliar. O silício atuou como indutor de resistência a M. persicae em batata.

Silicon influence on resistance induction against Bemisia tabaci biotype B (Genn.) (Hemiptera: Aleyrodidae) and on vegetative development in two soybean cultivars

“…Nymphal survival, at least through the 3rd and 4th instars, was not signi icantly different between the two untreated (Table 2). These results are similar to those of Correa et al (2005) who observed a higher nymphal mortality of B. tabaci biotype B after foliar application of silicon on cucumber plants, probably due to an increase in the plants defensive compounds induced by a higher activity of oxidative enzymes (Gomes et al 2008).…”

“…In addition, no effect of silicon on the vegetative development of soybeans was observed; the mean weights found for root and aerial parts, and the root:aerial parts ratio were the same for silicon-treated or untreated (Table 5). Although silicon has been demonstrated not to affect the dry weight of the aerial parts of several plants (Costa et al 2007, Tokura et al 2007, Gomes et al 2008, Smith et al 2008, changes in the root:aerial parts ratio observed in our laboratory tests must be investigated under ield conditions.…”

“…Samples were used for the analysis of phenolic compounds, lignin and non-protein organic nitrogen following Gomes et al (2008).…”

“…It has also been shown that silicon can indirectly stimulate the vegetal development and plant yield due to the protection against abiotic, such as the hydric stress (Korndörfer et al 2004), and biotic ones, such as insect pests (Gomes et al 2008 and diseases (Moraes et al 2006). Some of these responses might be due to the fact that silicon application can probably trigger natural plant defensive mechanisms, such as the production of phenolic compounds, chitinases, peroxidases and lignin (Chérif et al 1994, Epstein 1999, Gomes et al 2008, which can all interfere with the physiology and development of insect pests.…”

Características anatômicas de mudas de morangueiro micropropagadas com diferentes fontes de silício

“…Contudo, do ponto de vista fi siológico, para o crescimento e o desenvolvimento das plantas, o silício tem demonstrado efeito benéfi co sobre o aumento de produção de diversas culturas (Gomes et al, 2008). Acredita-se que ele possa interferir na arquitetura das plantas e favorecer a fotossíntese, ao proporcionar folhas mais eretas, que têm maior efi ciência fotossintética.…”