Application rate trials with a nuclear polyhedrosis virus to control Spodoptera frugiperda (Smith) on maize

Abstract

Different concentrations of nuclear polyhedrosis virus were applied as aqueous suspensions using a tractor mounted or a backpack-manual sprayer to control Spodoptera frugiperda (Smith) larvae on maize (Zea mays L.). Larval mortality varied with the application equipment. For the tractor-mounted sprayer application of at least 2.5 x 10(12) P.I.B./ha was necessary to attain a control comparable to that obtained with the backpack-manual sprayer application (70.2%). For this application method it can be used the dose of 2.5 x 10(11) PI.B./ ha, butNPV persistence was very short. A greaterNPV persistence was obtained with doses over 1.25 x 10(12) P.I.B./ha (93.4% mortality). The occurrence of parasitoids in the experimental area increased larval mortality rate (16.4%), independent of the application method. Among the parasitoids, the most prevalent was Campoletis flavicincta (Ashmead) (53.0%), followed by Chelonus insularis (Cresson) (31.3%), and Eiphosoma spp. (15.6%).

Aspectos Biológicos de Campoletis Flavicincta (Ashmead) ( Hymenoptera: Ichneumonidae) e Interações com o Vírus da Poliedrose Nuclear de Spodoptera frugiperda

“…As lagartas, quando expostas ao vírus, tinham idade entre três e cinco dias (segundo e terceiro ínstares), considerada a melhor fase para a produção do parasitóide (Cruz et al, 1997a). A infecção com o VPN -Sf ocorreu quando as lagartas permaneceram por 24 h alimentando-se de discos de folhas de milho (2,5 cm de diâmetro), umedecidas com o vírus, na concentração de 6 x 10 6 poliedros/ml.…”

“…A lagarta-do-cartucho Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) impõe grandes perdas à produção de milho (Zea mays L.) não só no Brasil, mas em toda a América (Cruz & Turpin, 1983, Cruz et al, 1997a, 1999, Figueiredo et al, 2006.…”

Estudos de Bacillus thuringiensis Berliner visando ao controle de Spodoptera frugiperda (J.E.Smith).

“…A compatibilidade com outros bioinseticidas ou com agentes naturais de controle é importante no desenvolvimento de estratégias que utilizam entomopatógenos em programas de Manejo Integrado de Pragas (Gardner et al 1984 (Cruz et al, 1996), na formulação de pó molhável.…”

Using sex pheromone traps in the decision-making process for pesticide application against fall armyworm (Spodoptera frugiperda[Smith] [Lepidoptera: Noctuidae]) larvae in maize

“…Alternatives for managing this pest are currently being explored, including the use of biological control agents (Rezende et al 1995;Cruz et al 1997Cruz et al , 2002Figueiredo et al 1999;Cisneros et al 2002;Mendez et al 2002;Molina-Ochoa et al 2003), cultural techniques (Cruz et al 1996Farias-Rivera et al 2003), host-plant resistance (Yu et al 2003), genetically modified crops (Fernandes et al 2003), and pheromones (Malo et al 2001;Batista-Pereira et al 2006).…”