Efeito inseticida sistêmico de nanoformulações à base de nim sobre Bemisia tabaci (Hemiptera: Aleyrodidae) biótipo B em tomateiro

Abstract

ResumoEste estudo avaliou a ação inseticida sistêmica e o efeito residual de nanoformulações à base de derivados de nim (Azadirachta indica A. Juss, Meliaceae) sobre ninfas de Bemisia tabaci biótipo B (Hemiptera: Aleyrodidae), espécie-praga de diversas culturas de importância econômica. Suspensões coloidais contendo nanocápsulas carregadas com produtos derivados de A. indica foram preparadas utilizando polímeros biodegradáveis como poli-ε-caprolactona (PCL) e poli-β-hidroxibutirato (PHB). A matriz encapsulada era composta por uma formulação comercial contendo uma quantidade enriquecida e conhecida dos limonoides azadiractina e 3-tigloilazadiractol (Azamax  1,2 CE). Inicialmente foi estimada a CL 50 , para ninfas de B. tabaci, de soluções contendo óleo de nim, que foram aplicadas via água de irrigação (solo) em tomateiro. Posteriormente, dois lotes de nanoformulações, com variação no tipo e quantidade dos polímeros e na quantidade do óleo comercial, foram testados quanto à ação sistêmica. As nanoformulações NC L5-2 (com nanocápsulas de PCL) e NC L6-1 (com nanocápsulas de PHB), as mais eficazes entre as testadas, foram avaliadas quanto ao efeito residual. A CL 50 estimada foi de 180,67 mg L -1 de azadiractina. Constatou-se também que a ação sistêmica de óleos e nanoformulações contendo compostos de nim dependem das condições ambientais em que são aplicados. O Azamax  não apresenta efeito deterrente sobre a oviposição, nem age sobre o desenvolvimento embrionário da mosca-branca quando aplicado via água de irrigação no solo no momento da infestação. As nanoformulações selecionadas são bioativas mesmo cerca de 30 dias após a aplicação, não diferindo do produto comercial.Palavras-chave: nanotecnologia, bioatividade, MIP, Azadirachta indica. Systemic insecticidal effect of neem-based nanoformulations against Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B in tomato AbstractThis study evaluated the systemic insecticidal action and the residual effect of neem-based nanoformulations (Azadirachta indica A. Juss, Meliaceae) on Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) nymphs, a pest of several economic important crops. Colloidal suspensions containing nanocapsules loaded with derived products from A. indica were prepared by using biodegradable polymers such as poly-ε-caprolactone (PCL) and poly-β-hydroxybutyrate (PHB).The encapsulated matrix was a commercial formulation, which contained not only enriched amount of limonoids azadirachtin and 3-tigloilazadiractol, but also in known quantities (Azamax  1.2 CE). Initially, it was estimated the LC 50 of solutions containing neem oil, which were applied through irrigation water (soil) in tomato in order to control nymphs of B. tabaci. Afterwards, two lots of nanoformulations, varying in type and amount of polymers and in quantity of commercial oil, were evaluated for systemic action. The nanoformulations NC L5-2 (nanocapules in PCL) and NC L6-1 (nanocapsules in PHB) caused higher mortality among others and for this reason were assayed for residual effect. The estimat...

Characterization of Nanospheres Containing Zanthoxylum riedelianum Fruit Essential Oil and Their Insecticidal and Deterrent Activities against Bemisia tabaci (Hemiptera: Aleyrodidae)

“…The higher efficiency of the essential oil in the second experiment is likely related to the environmental conditions, such as the lower relative humidity, corroborating Carvalho et al [ 60 ]. Many essential oil components are photounstable and thermolabile [ 48 ].…”

“…PCL nanoformulations containing neem oil killed 18.9% of 1st-instar B. tabaci nymphs, compared to 60% caused by the free form. In turn, Carvalho et al [ 60 ] obtained different results for two types of nanocapsules containing Azamax ® 1.2 EC, a commercial formulation enriched with azadirachtin and 3-tigloylazadirachtol. For the same concentration of Azamax, PCL, and poly-β-hydroxybutyrate (PHB) nanocapsules caused the mortality of 98% and 70.6% of B. tabaci nymphs, respectively.…”

Bioactivity of microencapsulated soursop seeds extract on Plutella xylostella

“…The same technology has also been used to control other groups of insects like in the research of CARVALHO et al (2015) who evaluated the efficacy of 19 nanoformulations of neem derivatives in controlling by systemic action nymphs of Bemisia tabaci (Genn., 1889) biotype B (Hemiptera: Aleyrodidae). Two nanoformulations (NC-2 and NCL5L6-1) were believed to cause similar mortality to the commercial neem oil.…”

Biogenic silica nanoparticles loaded with neem bark extract as green, slow-release biocide

“…Due its high potential as a green biocide, the neem extracts were already used to create controlled-release systems by using carbohydrates (b-cyclodextrin, starch and alginate) (Carvalho et al, 2012;Jerobin et al, 2012) and biodegradable polymers (polycaprolactone and polyhydroxybutyrate) (De Carvalho et al, 2015;Forim et al, 2013) as shell materials of nano/microcapsules; however, the high water retaining of these materials may accelerate the hydrolysis and release of neem compounds.…”