The spraying of herbicides in crops has become the main form of weed control. Although it means unexpected effects on non-target plants resulted by spraying drift. Thus, improvements in application techniques, as the best selection of spray nozzles and adjuvant, are essential to avoid environmental contamination and economic losses. On this work, we evaluate how much adjuvant associated with nozzles can reduce the spray drift. The nozzles used at experiment were air induction flat tip, hollow cone and twinjet and the spray liquids, which were composed of herbicide glyphosate and phosphatidylcholine + propionic acid adjuvant. Measurements were made at wind tunnel and droplet sizer, at laser diffraction method. The models of nozzles influence in droplet size characteristics and in occurrence of spray drift. The use of adjuvants reduces the spray drift only combined with the twinjet nozzle, while for the other models the adjuvant did not reduce the global spray drift at significant levels. The adjuvant reduced the spray drift until 39%, while the nozzles model reduced until 74%. Both techniques when combined were able to reduce until 80%. The model of nozzle has the biggest result on drift mitigation and the use of adjuvants can increase the drift mitigation specially with nozzles that produces smallest droplets.

Bacillus thuringiensis (Bt) is the main bacterium used in the formulation of bioinsecticides because it produces toxins and spores that are toxic to several orders of insects. The efficacy of Bt bioinsecticide is influenced by the quality of its application. The association with other crop protection products, such as adjuvants, can affect the physical and chemical parameters of the mixture. This study evaluated the physical and chemical parameters, volume median diameter (VMD), uniformity coefficient of droplets (SPAN), percentage of volume in drift droplets (%V <100 µm), contact angle, surface tension, potential of hydrogen (pH) and electrical conductivity (E.C.) of Bt bioinsecticides in concentrated suspension (SC), and wettable powder (WP) formulations associated with adjuvants. The largest droplet diameter and smallest values of drift droplets were found in the WP formulation with lower drift potential. The addition of mineral oil and surfactant to the mixtures of bioinsecticide reduced contact angle values and surface tension of the droplets, resulting in greater spreading of droplets in leaves. The addition of lecithin and propionic-acid-based adjuvants lowered the pH in both formulations. The adjuvants used in this study affected the physical and chemical characteristics of the mixtures, improving or impairing the quality of Bt bioinsecticide applications.

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Volumes de calda, uso de adjuvante e intervalos sem chuva no controle de plantas-daninhas com sulfentrazone 1Resumo -O herbicida sulfentrazone, utilizado na cultura canavieira, é recomendado para o controle de eudicotiledôneas e monocotiledôneas em pré-emergência, sendo também indicado para o controle de Panicum maximum e Ipomea hederifolia. A pesquisa foi realizada com o objetivo de verificar a influência das aplicações do herbicida sulfentrazone com e sem adjuvante em solo desprovido de cobertura por palha, sob diferentes períodos sem precipitação pluviométrica, associado a diferentes volumes de aplicação, para o controle de P. maximum e I. hederifolia. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições, no arranjo fatorial 2x2x6 + 1, ou seja, dois tratamentos de herbicida, dois volumes de calda (60 e 120 L ha -1 ), seis períodos sem chuva antes da aplicação e mais uma testemunha, que não recebeu aplicação de herbicida. Foram realizadas avaliações de contagem de plantas-daninhas a 15 e 33 dias após a chuva. Foi avaliada também a matéria seca da parte aérea das plantas. Os resultados indicam que a aplicação de sulfentrazone com todos os tratamentos foi eficaz no controle I. hedrifolia, independente do volume de calda, período sem chuva ou presença de adjuvante. Mesmo havendo escape de plantas de P. maximum (emergência de plantas) em todos os períodos sem chuva, os tratamentos são eficazes para o controle da espécie. A presença do óleo mineral na calda com o herbicida sulfentrazone não incrementa o controle de P. maximum e I. hederifolia.Abstract -The herbicide sulfentrazone, used in sugarcane cultivation, is recommended for the control of eudicots and monocotyledons in pre-emergence and is also indicated for the control of Panicum maximum and Ipomea hederifolia. The research was carried out with the objective of verify the influence of the sulfrentazone herbicide with and without adjuvant on soil without straw