Granular phagostimulant nucleopolyhedrovirus formulations for control of Spodoptera frugiperda in maize (original) (raw)
Related papers
Anais da Sociedade Entomológica do Brasil, 1997
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%).
Biological Control, 2002
Spinosad (Dow AgroSciences) is a neurotoxin mixture produced during fermentation of a soil actinomycete that has high activity towards Lepidoptera. Diet surface contamination bioassays were performed with Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) and Spinosad alone and in mixtures. The interaction of SfMPNV + Spinosad mixtures in S. frugiperda larvae was generally independent or slightly antagonistic in nature, although weak synergism was detected in mixtures containing 3 ppm Spinosad + 20 or 70 occlusion bodies/mm 2 diet of SfMNPV. Mean time to death was not a reliable indicator of mortality over time in larvae exposed to SfMNPV-Spinosad mixtures because Spinosad killed larvae quickly whereas virus mortality occurred at a much lower rate. Therefore, threshold tolerance analysis was employed to generate time-response curves that showed two clear phases; an initial response to Spinosad until $100 h followed by virus-induced mortality at 120-250 h post-contamination. A field trial was performed to assess the degree of pest control achieved by SfMNPV-Spinosad mixtures applied to maize. Recovery of S. frugiperda larvae was significantly reduced in all treatments compared to recovery from control plots. The mixture of SfMNPV with 3 ppm Spinosad resulted in ca. 90% S. frugiperda control, which was 12.5-32% greater than for plots treated with SfMNPV alone. The impact of low concentrations of Spinosad on non-target arthropods present in the maize crop was evaluated in a field trial. Application of 3 ppm Spinosad had very little effect on the abundance of insect natural enemies present on maize plants, whereas application of the product label recommended rate of 200 ppm Spinosad had effects similar to those observed following application of chlorpyrifos. The use of low concentrations of Spinosad merits further study as a means of controlling lepidopteran pests either alone or in combination with other entomopathogens. Ó
Journal of Pest Science, 2009
The multiply-enveloped nucleopolyhedrovirus (SeMNPV) of Spodoptera exigua (Hübner) is being employed on an increasing scale as the basis for bioinsecticidal products for control of this pest in greenhouse crops in Europe. The mortality of diet-reared S. exigua larvae was determined after feeding on lettuce leaf discs contaminated by mixtures of SeMNPV occlusion bodies and 1 of 13 substances reported to have phagostimulant properties. Of the substances tested, wheatgerm and soya Xour resulted in sig-niWcantly increased mortality compared to the virus alone. However, these preferences disappeared when larvae were reared on lettuce. We conclude that (1) the activity of potential phagostimulant substances depends on the prior feeding experience of S. exigua and, (2) laboratory tests using diet-reared insects require validation using plantreared larvae before being developed for Weld testing.
Comparative Field Stability of Selected Entomopathogenic Virus Formulations
Journal of Economic Entomology, 2001
Nucleopolyhedroviruses originally isolated from Anagrapha falcifera (Kirby) and Autographa californica (Speyer) were formulated with various ingredients using a spray dry method and tested for residual Þeld activity in Illinois and Mississippi. In Mississippi, Þeld tests were conducted on cotton in 1997, whereas in Illinois tests were conducted on cabbage in 1997 and 1998. Within 24 h, signiÞcant differences were observed among formulations in all tests. Unformulated virus had signiÞcantly less insecticidal activity than formulated virus and formulations containing lignin retained activity signiÞcantly longer than other formulations. Relatively small amounts of Blankophor BBH, when encapsulated within the formulation, did not greatly enhance (Ͼ10ϫ) insecticidal activity based on LC 50 determinations nor prolong insecticidal activity based on Þeld evaluations. In most tests, Ͼ50% activity remained in formulations containing lignin, whereas unformulated virus retained Ͻ50% activity within 24 h after application.
Biocontrol Science and Technology, 1992
Agrotis segetum nuclear polyhedrosis virus (AsNPV) and granulosis virus (AsGV), propagated in laboratory cultures of A. segetum in England and A. ipsilon in Spain, respectively, were applied to plots of maize plants at the one-to four-leaf stage of growth. Plots were arranged in a 6 X 6 Latin square design and infested with second-instar A. segetum larvae (the comnwn cutworm). Each virus was applied in separate treatments by two application methods; as an aqueous spray containing 0.1 % Agral as a wetting agent, and as abran bait. The NPV was applied at arate of 4 X 1012 polyhedra/ha, and the GVat 4 X 1013 granules/ha. Soil and plants were sampled fQr larvae on three occasions following virus treatment: 24 h, 4 days and 11 days. The larvae were reared on diet in the laboratory, until death or pupation, to examine the rafe and level of viral infection. lnfection data showed 87.5% and 91 % NPV infection and 12.5% and 55% GV infection in spray and bait treatments, respectively, in larvae sampled 24 h after treatment. In larvae sampled 4 days after treatment, the results were 78% andl00% NPVinfection, and 13% and 6% GVinfectiqn. A totalofonly six larvae were retrieved on day 11. In both treatments larvae infected wi~ AsNPV died significantly more rapidly and at an earlier instar than those infected with AsGV, indicating that AsNPV appears to have better potential as a control agent for A. segetum.
Biocontrol Science …, 1992
Agrotis segetum nuclear polyhedrosis virus (AsNPV) and granulosis virus (AsGV), propagated in laboratory cultures of A. segetum in England and A. ipsilon in Spain, respectively, were applied to plots of maize plants at the one-to four-leaf stage of growth. Plots were arranged in a 6 X 6 Latin square design and infested with second-instar A. segetum larvae (the comnwn cutworm). Each virus was applied in separate treatments by two application methods; as an aqueous spray containing 0.1 % Agral as a wetting agent, and as abran bait. The NPV was applied at arate of 4 X 1012 polyhedra/ha, and the GVat 4 X 1013 granules/ha. Soil and plants were sampled fQr larvae on three occasions following virus treatment: 24 h, 4 days and 11 days. The larvae were reared on diet in the laboratory, until death or pupation, to examine the rafe and level of viral infection. lnfection data showed 87.5% and 91 % NPV infection and 12.5% and 55% GV infection in spray and bait treatments, respectively, in larvae sampled 24 h after treatment. In larvae sampled 4 days after treatment, the results were 78% andl00% NPVinfection, and 13% and 6% GVinfectiqn. A totalofonly six larvae were retrieved on day 11. In both treatments larvae infected wi~ AsNPV died significantly more rapidly and at an earlier instar than those infected with AsGV, indicating that AsNPV appears to have better potential as a control agent for A. segetum.
Evaluation of a Baculovirus Bioinsecticide for Small-Scale Maize Growers in Latin America
Biological Control, 1999
Near identical trials conducted concurrently in maize plots in Honduras and Mexico produced similar results in the pattern of larval mortality of Spodoptera frugiperda following application of a baculovirus or a conventional synthetic insecticide. The highest application rates of virus resulted in approximately 40% mortality of S. frugiperda larvae. Virus-induced mortality decreased with time. Parasitism by wasps and tachinids also contributed up to 40% mortality in field-collected larvae. The application of chlorpyrifos resulted in a resurgence of S. frugiperda. Chlorpyrifos also reduced a number of important predators in the maize crop which is likely to have been influential in the observed resurgence of this pest. The use of granulated sugar in the viral formulation caused an increase in the population density of several maize-associated insect species, and in Mexico a transient increase in parasitism was observed in sugar-treated plots. Sugar did not appear to increase the probability of infection by acting as a feeding stimulant in either trial. A preliminary analysis of the cost of viral production and application indicates that virus was considerably more costly than conventional control. To be commercially viable, economies of scale both in the cost of raw material for the insect diet and in the efficiency of manpower-related activities are needed to substantially reduce the costs of the viral product. Despite high levels of infestation by S. frugiperda, grain weight/ cob was not significantly improved by the application of the biological or synthetic insecticide. Natural mortality factors both biotic and abiotic appear to have a large impact on larval S. frugiperda populations. For improvements in yield, the impact of control measures against S. frugiperda may be dependent on plant growth stage. Trials on timing and frequency of virus application are in progress to test this idea. 1999 Academic Press
Revista Brasileira de Milho e Sorgo
The efficiency of Baculovirus in a wettable powder formulation to control the fall armyworm Spodoptera frugiperda (Smith) was evaluated using variations of the recommended dose of 50 grams per hectare (2.5 x 10 11 polyhedron inclusion bodies-PIB ha-1): 50 or 100 g ha-1 applied once, and variations of two applications at seven-day intervals, of 25+25, 25 + 50, 50+25 and 50+50 g ha-1 , compared to untreated plots. The treatments were arranged in a randomized complete block design with six replications. Each plant at 6-8 or 8-10-leaf growth stages, was artificially infested with 10 newly hatched larvae. The virus suspension (300 L ha-1) was applied 24 hours after larvae infestation using a back-pack-manual sprayer at 40 PSI (2.8 kg cm-2) and a regular flat fan nozzle. Larval mortality rate obtained from plots with the application of 50 g of Baculovirus wettable formulation ha-1 , at once (96.2%), was significantly higher than that obtained with the application of 25+25 g ha-1 (85.3%) or 25 + 50 g ha-1 (87.8%). However, it was lower than that obtained from the other virus treatments, which had no significant difference among them (mean of 99.2%). The damage caused by S. frugiperda on the leaves of plants of untreated plots (average of 4.5 in an visual scale from 1 to 5) was significantly different from that observed in plots sprayed with virus (1.75 to 2.33). Plants protected with the virus produced significantly higher yield (mean of 7,577 kg ha-1) than plants unprotected (6,140 kg ha-1), that is, 23.4% higher.
Crop Protection, 1994
Efeito de Diferentes Doses de Virus de Poliedrose Nuclear para o Controle de Spodoptera frugiperda (Smith) em Milho RESUMO-Diferentes concentrações de vírus da poliedrose nuclear (VPN) foram aplicadas em suspensão aquosa, usando-se pulverizador (acoplado a um trator ou costal-manual), para o controle de larvas de Spodoptera frugiperda (Smith), em milho (Zea mays L.). A mortalidade das larvas variou com o equipamento de aplicação. Na aplicação via trator, foi necessária uma dose de pelo menos 2,5 x 10 12 corpos de inclusões poliédricas (CIP)/ha para se ter eficiência comparável a que se obteve com o pulverizador costal-manual (70,2%). Para este tipo de pulverizador pode-se usar 2,5 x 10 11 CIP/ha, porém o efeito residual foi muito curto. Maior persistência foi obtida com doses acima de 1,25 x 10 12 CIP/ ha (93,4% de mortalidade). A ocorrência de parasitóides na área experimental propiciou um aumento médio na taxa de mortalidade larval (l6,4%), independente da metodologia de aplicação. Entre os parasitóides, a maior ocorrência foi de Campoletis flavicincta (Ashmead) (53,0%), seguido por Chelonus insularis (Cresson) (31,3%), e Eiphosoma spp. (15,6%). PALAVRAS-CHAVE Insecta, lagarta-do-cartucho, Baculovirus, controle biológico. 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%).
Journal of Invertebrate Pathology, 2012
Three biopesticide parameters were evaluated for a fast-killing isolate (3AP2) and a wild-type isolate (Sf3) of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV). Both isolates were evaluated for virus production using in vivo methods, for speed of kill based on bioassay of applications to glasshouse-grown and field-grown plants, and for residual insecticidal activity of unformulated virus and an encapsulating formulation to provide UV protection. Two inoculation rates comparing relative in vivo production of the isolates demonstrated 3AP2 inoculated larvae were significantly smaller than Sf3 inoculated larvae at death. At the lower inoculation rate, Sf3 inoculated larvae produced approximately twofold more occlusion bodies as the 3AP2 inoculated larvae. A model system of applications to cabbage plants and a bioassay to observe mortality of neonate S. frugiperda (J.E. Smith) after feeding on samples of treated leaves was used to evaluate speed of kill and residual insecticidal activity. The LT 50 for the 3AP2 isolate was at least 30 h less than the LT 50 for the Sf3 isolate when applied to either glasshouse-grown or field-grown plants. The spray-dried lignin encapsulating formulation provided similar benefits to both virus isolates when exposed to simulated sunlight in the laboratory and to natural sunlight in the field. For treatment applications to field grown cabbage in June, the half-life for efficacy of unformulated virus was <7.5 h compared with a half-life of >26.7 h for encapsulated virus. These results demonstrate that improved technologies can be combined to address characteristics which otherwise can limit the commercial potential of microbial-based biological insecticides.