Influência da dureza e potencial hidrogeniônico da calda de pulverização sobre o controle do ácaro-da-leprose em frutos de laranja doce
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Data
2011-01-01
Autores
Prado, Evandro Pereira [UNESP]
Araújo, Demétrius de [UNESP]
Raetano, Carlos Gilberto [UNESP]
Pogetto, Mário Henrique Ferreira do Amaral Dal [UNESP]
Aguiar-Júnior, Hélio Oliveira [UNESP]
Christovam, Rafael de Souza [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Instituto Agronômico de Campinas
Resumo
Muitos são os relatos de ineficiência de agrotóxicos no controle de pragas quando estes são preparados em soluções com água dura e pH elevado. Assim, o trabalho teve como objetivo avaliar o efeito da dureza da água e o pH de soluções acaricidas, em diferentes períodos de tempo após o preparo da calda (0 e 24 horas) no controle do ácaro-da-leprose Brevipalpus phoenicis (Geijskes). O bioensaio foi conduzido sobre frutos de Citrus sinensis (L.) Osbeck cv. Valência. Utilizou-se o delineamento inteiramente ao acaso, com 14 tratamentos e 4 repetições, sendo a parcela experimental composta de um fruto com 10 fêmeas do acarino por fruto. Os acaricidas testados nas dosagens registradas foram: propargite, hexitiazoxi e espirodiclofeno. A pulverização dos frutos foi feita em torre de Potter adaptada, conferindo um volume equivalente a 1616 L ha-1. As avaliações foram realizadas até 49 dias após aplicação dos produtos, contando o número de adultos, ninfas e, na avaliação final, o número de ovos do acarino por fruto. A dureza da água, pH e tempo de preparo não interferiram no controle do ácaro da leprose. Os acaricidas, após mistura com os diferentes tipos de água, não alteraram o pH das soluções, os quais mostraram pequenas variações de pH no decorrer de 24 horas. Todos os acaricidas propiciaram alta eficácia de controle do acarino nas diferentes condições de preparo de calda, mostrando que esses fatores não interferiram no potencial acaricida.
There are many reports of inefficiency by pesticides in the pest control when they are prepared in solutions with water hardness and high pH. Therefore, the research aimed to evaluate the effects of water hardness, pH and time after preparation (0 and 24h) of acaricides spray solutions on control of the citrus leprosis mite, Brevipalpus phoenicis (Geijskes). The bioassay was carried out on fruit of Citrus sinensis (L.) Osbeck cv. Valência. A completely randomized design with fourteen treatments and four repetitions was used. The sample unit was composed by one fruit with ten mite females. The following acaricides were tested: propargite, hexythiazox and spirodiclofen. The spray on fruit was done by modified Potter tower adjusted to an equivalent volume of 1616 L ha-1. The evaluations were done until 49 days after the acaricide application by counting the number of adults, nymphs and the number of eggs in the last evaluation. Water hardness, hydrogenionic potential and time after preparation of spray solution did not interfere on leprosis mite control. After the mixture with different water types, the acaricides did not modify the pH of the spray solutions, which showed low variations in pH values over 24 h. All acaricides showed an efficient control of leprosis mite, regardless of the variations in water hardness and pH.
There are many reports of inefficiency by pesticides in the pest control when they are prepared in solutions with water hardness and high pH. Therefore, the research aimed to evaluate the effects of water hardness, pH and time after preparation (0 and 24h) of acaricides spray solutions on control of the citrus leprosis mite, Brevipalpus phoenicis (Geijskes). The bioassay was carried out on fruit of Citrus sinensis (L.) Osbeck cv. Valência. A completely randomized design with fourteen treatments and four repetitions was used. The sample unit was composed by one fruit with ten mite females. The following acaricides were tested: propargite, hexythiazox and spirodiclofen. The spray on fruit was done by modified Potter tower adjusted to an equivalent volume of 1616 L ha-1. The evaluations were done until 49 days after the acaricide application by counting the number of adults, nymphs and the number of eggs in the last evaluation. Water hardness, hydrogenionic potential and time after preparation of spray solution did not interfere on leprosis mite control. After the mixture with different water types, the acaricides did not modify the pH of the spray solutions, which showed low variations in pH values over 24 h. All acaricides showed an efficient control of leprosis mite, regardless of the variations in water hardness and pH.
Descrição
Palavras-chave
Controle químico, qualidade da água de pulverização, ácaro-da-leprose, citros, Chemical control, spray water quality, leprosis mite, citrus
Como citar
Bragantia. Instituto Agronômico de Campinas, v. 70, n. 2, p. 389-396, 2011.