Avaliação de tecnologias de aplicação de nematóides entomopatogênicos visando o controle de Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) na cultura do milho
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Data
2006-07-21
Autores
Garcia, Luiz Cláudio [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A tecnologia de aplicação desenvolvida para produtos químicos tem sido utilizada para organismos entomopatogênicos sem o estudo prévio das necessidades de adaptações que visem à manutenção da viabilidade desses agentes de controle biológico. Assim, o objetivo dessa pesquisa foi avaliar o efeito de diferentes tecnologias de aplicação sobre a concentração, viabilidade e eficácia dos juvenis infectantes dos nematóides Heterorhabditis indica e Steinernema sp. no controle da lagartas-do-cartucho (Spodoptera frugiperda), em terceiro instar, na cultura do milho. Testaram-se as dosagens de zero a 400 juvenis infectantes em placa de Petri para controle da lagarta-do-cartucho. As tecnologias de aplicação dos entomopatógenos, em ambiente controlado, abrangeram as pulverizações com pontas hidráulicas e centrífuga, com e sem fornecimento de carga elétrica à calda. Na pulverização do Steinernema sp. em plantas de milho sob condição ambiental controlada, com e sem emprego de tensoativo e lâmina de água, as dosagens variaram entre zero e 288 milhões.ha-1. Conclui-se que para matar as lagartas em terceiro ínstar de S. frugiperda em laboratório foram necessários 280 juvenis infectantes de Steinernema sp. Pode-se pulverizar os entomopatógenos, sem que haja perda significativa na concentração e viabilidade desses organismos, com equipamentos que forneçam carga elétrica à calda, ponta centrífuga e pontas hidráulicas, exceto àquelas que requerem elementos filtrantes com malha igual a 100. Os tensoativos Break-Thru®, Extravon® e Iharaguen- S® não afetaram a viabilidade dos entomopatógenos. A pulverização em plantas de milho (V6) com até 288 milhões de juvenis infectantes de Steinernema sp. por hectare, diluídos em volume de calda de até 800 L.ha-1 com 0,01 % de tensoativo ou nesse volume seguido de exposição à chuva artificial (lâmina de água de 6 mm) não proporcionaram adequado controle da praga.
Spraying technologies has been developed to work with agrochemicals, but it has been utilized with entomopatogenic organisms without a prior study of adaptation that will help maintain the viability of the biological control agents. In this way, the objective of this research was to evaluate the effect of different spraying technologies on the concentration, viability and efficiency of the infective juveniles of Heterorhabditis indica and Steinernema sp. nematodes to control fall armyworm (Spodotera frugiperda) at the third instar on corn plants. Rates between zero and 400 infective juveniles were tested in a Petri dish against fall armyworm. The study to evaluation spraying technologies stable environment, involved hydraulic nozzles and rotary spray nozzles with and without electrical charge added to the spraying mix. The dosages of Steinernema sp. sprayed on corn plants in controlled environment with or without adjuvant agent and water blade, varied of zero at 288 millions ha-1. For killing 100% the fall armyworm in laboratory, it was necessary 280 juvenile infectants of Steinernema sp. It is possible to spray entomopatogenic organisms without an significative loss in the concentration and viability of these organisms, with equipment that produces electrical charges to the spraying mix, and with those using hydraulic and rotary nozzles tips, but without mash 100 filtrating elements. Tensoactive agents Break-Thru®, Extravon® and Iharaguen-S® did not affect the viability of the entomopatogens. Spraying corn plants with up to 288 millions of juvenile infectants of Steinernema sp. per hectare, diluted in the spraying mix up to 800 L.ha-1, with 0,01% of tensoactive agent or in this volume followed by artificial rain (water blade of 6 mm), was not enough to control the infestation.
Spraying technologies has been developed to work with agrochemicals, but it has been utilized with entomopatogenic organisms without a prior study of adaptation that will help maintain the viability of the biological control agents. In this way, the objective of this research was to evaluate the effect of different spraying technologies on the concentration, viability and efficiency of the infective juveniles of Heterorhabditis indica and Steinernema sp. nematodes to control fall armyworm (Spodotera frugiperda) at the third instar on corn plants. Rates between zero and 400 infective juveniles were tested in a Petri dish against fall armyworm. The study to evaluation spraying technologies stable environment, involved hydraulic nozzles and rotary spray nozzles with and without electrical charge added to the spraying mix. The dosages of Steinernema sp. sprayed on corn plants in controlled environment with or without adjuvant agent and water blade, varied of zero at 288 millions ha-1. For killing 100% the fall armyworm in laboratory, it was necessary 280 juvenile infectants of Steinernema sp. It is possible to spray entomopatogenic organisms without an significative loss in the concentration and viability of these organisms, with equipment that produces electrical charges to the spraying mix, and with those using hydraulic and rotary nozzles tips, but without mash 100 filtrating elements. Tensoactive agents Break-Thru®, Extravon® and Iharaguen-S® did not affect the viability of the entomopatogens. Spraying corn plants with up to 288 millions of juvenile infectants of Steinernema sp. per hectare, diluted in the spraying mix up to 800 L.ha-1, with 0,01% of tensoactive agent or in this volume followed by artificial rain (water blade of 6 mm), was not enough to control the infestation.
Descrição
Palavras-chave
Milho, Pragas agricolas - Controle biologico, Pulverização, Lepidoptero, Biological control, Application technology, Steinernema
Como citar
GARCIA, Luiz Cláudio. Avaliação de tecnologias de aplicação de nematóides entomopatogênicos visando o controle de Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) na cultura do milho. 2006. v, 55 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2006.