Distribution pattern, surface tension and contact angle of herbicides associated to adjuvants on spraying and control of Ipomoea hederifolia under rainfall incidence

Abstract

Scarlet Morning Glory is considered to be an infesting weed that affects several crops and causes serious damage. The application of chemical herbicides, which is the primary control method, requires a broad knowledge of the various characteristics of the solution and application technology for a more efficient phytosanitary treatment. Therefore this study aimed to characterize the effect of rainfall incidence on the control of Ipomoea hederifolia, considering droplet size, surface tension, contact angle of droplets formed by herbicides liquid on vegetal and artificial surfaces, associated to adjuvants and the volumetric distribution profile of the spray jet. The addition of the adjuvants to the herbicide spraying liquid improved the application quality, as it influenced the angle formed by the spray by broadening the deposition band of the spray nozzle and thus the possible distance between the nozzles on spray boom and due the changes at droplet size, which contribute to a safety application. The rainfall occurrence affected negatively the weed control with the different spraying liquids and also the dry matter weight, suggesting that the phytosanitary product applied was washed off.KEYWORDS: application technology, scarlet morning glory, glyphosate, paraquat. PADRÃO DE DISTRIBUIÇÃO, TENSÃO SUPERFICIAL E ÂNGULO DE CONTATO DE CALDAS HERBICIDAS ASSOCIADAS A ADJUVANTES EM PULVERIZAÇÃO E CONTROLE DE Ipomoea hederifolia SOB INCIDÊNCIA DE CHUVARESUMO: A corda-de-viola é considerada uma planta daninha infestante de diversas culturas, causando importantes prejuízos. A aplicação de herbicidas químicos, principal método de controle, requer o conhecimento de diversas características da calda e da tecnologia de aplicação para tornar o tratamento fitossanitário mais eficiente. Diante disso, este trabalho teve como objetivo caracterizar o efeito da incidência de chuvas no controle de Ipomoea hederifolia, considerando o tamanho das gotas, a tensão superficial, o ângulo de contato de gotas formadas por caldas herbicidas em superfícies vegetais e artificiais, associados a adjuvantes e o perfil de distribuição volumétrica do jato pulverizado. A adição dos adjuvantes na calda herbicida melhorou a qualidade da aplicação, pois influenciou no ângulo formado pelo jato de pulverização, ampliando a faixa de deposição da ponta, e diminuiu as gotas suscetíveis à deriva divido às alterações no tamanho das gotas, o que contribui para uma aplicação de segurança. A incidência de chuva afetou negativamente o controle das plantas daninhas nas diferentes caldas e também o peso de massa seca, indicando uma lavagem dos produtos aplicados.PALAVRAS-CHAVE: tecnologia de aplicação, corda-de-viola, glifosato, paraquat.

Air‐assisted spraying and electrically charged droplets for Bemisia tabaci control in soybeans

“…The diameter spectrum of droplets produced by spraying techniques was determined in a Mastersizer S® particle size analyzer (Malvern Instruments Co.), version 2.19, in which an optical unit determines the droplet diameter within the sprayed spectrum through the trajectory deviation suffered by the laser when reaching them. 9 The spraying was activated with air-assisted sprayer with electrically charged droplets, the characteristics of sprayer used are described in Section 2.2.1 and Fig. 1.…”

Exploring alternatives for assessing and improving herbicide use in intensive agroecosystems of South Asia: A review

“…Higher efficiency of weed control using chemical management can be achieved through the adoption of herbicide sequence, herbicide rotation, development of novel herbicides and herbicide mixtures, use of synergists, new formulations, or new adjuvants; and use of appropriate herbicide rates (Calore et al, 2015). Besides improving efficiency, they can also delay the development of resistance (Gressel, Segel, 1990).…”

Metabolomics Response of Wheat (Triticum aestivum) to “Green” and Conventional Nonionic Surfactants at Different Application Stages

“…A mixture of xanthan gum and triethyl citrate was considered an alternative “green” surfactant agent. The polysaccharide xanthan gum can be generated via microbial fermentation, and has high biodegradability and compatibility with other chemical agents. , Triethyl citrate is an ester of naturally derived citric and has been investigated as an adjuvant in agriculture . This Green SA has shown the potential to deliver active ingredients into plant surfaces by increasing wettability and moisture retention times .…”

“…35,36 Triethyl citrate is an ester of naturally derived citric and has been investigated as an adjuvant in agriculture. 37 This Green SA has shown the potential to deliver active ingredients into plant surfaces by increasing wettability and moisture retention times. 36 A full life-cycle assessment would be needed to determine the environmental benefits of the Green SA over more conventional SAs, but that is beyond our current scope.…”