Time filter

Source Type

Evaristo A.B.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Matos F.S.,Federal University of Goais | de Freitas R.G.,Federal University of Viçosa | And 2 more authors.
Experimental and Applied Acarology | Year: 2013

The broad mite Polyphagotarsonemus latus is a key pest of physic nut (Jatropha curcas L.). The purpose of this study was to identify physic nut accessions that are less susceptible to P. latus, in support of the breeding program of J. curcas. We first evaluated population growth rate and injury symptoms of P. latus on different J. curcas accessions and then carried out physiological analyses on P. latus-infested and uninfested accessions. From the germplasm bank of the Federal University of Viçosa, 15 physic nut accessions with high seed oil content, with different genetic background, were tested. The following traits were evaluated: instantaneous population growth rate of P. latus (r i), injury symptoms, relative leaf water content, specific leaf area, gas exchange, photosynthetic pigments, nitrogen and biomass of the aerial part. Significant differences were observed for P. latus population growth rate and injury symptoms among accessions. A positive correlation between P. latus growth rate and injury was found. The UFVJC72 accession stood out as the more resistant, considering P. latus growth rate and injury symptoms, compared with most accessions. Physiological responses did not vary among accessions, but did between infested and uninfested plants. In P. latus-infested plants, net photosynthesis was on average 50.5 % lower than in uninfested plants, whereas stomatal conductance and transpiration decreased by 46.2 and 51.6 %, respectively. © 2013 Springer Science+Business Media Dordrecht.

Rodriguez-Cruz F.A.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Pinto C.M.F.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG
Experimental and Applied Acarology | Year: 2013

Amblyseius herbicolus (Banks) is found associated with broad mites Polyphagotarsonemus latus in crops such as chili pepper in Brazil. The species has a potential for controlling P. latus, but little is known about its development and reproduction on this pest as well as on other food sources. We studied biological, reproductive and life table parameters of A. herbicolus on three different diets: broad mites, castor bean pollen (Ricinus communis) and sunnhemp pollen (Crotalaria juncea). The predator was able to develop and reproduce on all diets. However, its intrinsic growth rate was higher on the diet of broad mites or on castor bean pollen than on sunnhemp pollen. Differences among pollen species may be due to their nutritional content. Feeding on alternative food such as pollen can facilitate the predator's mass rearing and maintain its population on crops when prey is absent or scarce. Other strategies of using pollen to sustain predator population and reduce pest damage are discussed. © 2013 Springer Science+Business Media Dordrecht.

Tuelher E.S.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Guedes R.N.C.,Federal University of Viçosa | Pallini A.,Federal University of Viçosa
Crop Protection | Year: 2014

Organic coffee growers in Brazil often spray a wide range of organic-farming compatible products to control pests including the southern red mite, Oligonychus ilicis. However, most of these products have not yet been proven to be effective for mite control and there is no information about their side effects on natural enemies. We evaluated the lethal and sublethal effects of three organic compatible products, the biofertilizer Supermagro, a fresh bovine manure supplemented with micronutrients, bone meal, unrefined sugar, and milk to stimulate fermentation, an enriched Bordeaux mixture (Viça Café Plus®) and lime sulfur to O.ilicis and to its predatory mite Iphiseiodes zuluagai. Additionally, we evaluated the efficacy of these products against O.ilicis under greenhouse conditions. Only lime sulfur showed acute lethal effects at concentrations lower than the field recommended rates (20-40ml/l). The predatory mite I.zuluagai was more tolerant than its prey to the three products based on acute lethal concentration bioassays. The instantaneous rate of increase (ri) of O.ilicis when exposed to lime sulfur at field recommended rates was negative but ri of the predatory mite, I.zuluagai was not. The ri of the predatory mite was lower than that of its prey under Supermagro and Viça Café exposure, including at their field recommended rates (200ml/l and 10g/l, respectively). In a greenhouse experiment, the control efficacy against O.ilicis 14 days after spraying reached levels higher than 80% for all three products. Lime sulfur has the potential to control O.ilicis in organic coffee plantations. Although, Supermagro and Viça Café exhibited potential to control O.ilicis in the greenhouse, the product concentrations used were very high and may lead to selectivity problems. Therefore, spraying suitable concentrations of such products taking into account their effectiveness against O.ilicis and their selectivity to natural enemies are important for ecological pest management in organic coffee besides benefiting coffee plant nutrition. 22;Supermagro and Viça Café were effective only at high concentrations. © 2013 Elsevier Ltd.

Marques R.V.,Federal University of Tocantins | Sarmento R.A.,Federal University of Tocantins | Ferreira V.A.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | And 4 more authors.
Revista Colombiana de Entomologia | Year: 2014

In Brazil, smallholders produce the physic nut Jatropha curcas in association with crops such as pumpkin and corn, besides weeds. We evaluated the suitability of pumpkin and corn pollens, as well as pollen from a weed species (Peltaea riedelii), present in physic nut crop, as alternative food to predatory mites Euseius concordis and Iphiseiodes zuluagai. These species are natural enemies of Polyphagotarsonemus latus and Tetranychus bastosi, two important mite pests on J. curcas plants. The survival and oviposition rate of E. concordis and I. zuluagai were evaluated for five days on leaf discs supplied with pollen of pumpkin, corn or P. riedelii. Castor bean pollen (Ricinus communis) was provided to the predators as a control of suitable food. No significant difference on the oviposition rate of both I. zuluagai and E. concordis was observed when they fed with pollen from the three plants. However, the source of pollen affected the survival of the predatory mites. Pumpkin pollen was the worst food for both predatory mites while corn and P. riedelii was a better food. These results indicate the non-suitability of pumpkin pollen as alternative food to I. zuluagai and E. concordis. Corn and P. riedelli are sources of supplementary food to the predatory mites and can sustain predator populations when prey is scarce. © 2014 The American Society for Cell Biology.

Duarte M.V.A.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Bittencourt M.C.D.S.,Federal University of Viçosa | Rodriguez-Cruz F.A.,Federal University of Viçosa | And 3 more authors.
BioControl | Year: 2015

Many omnivorous arthropods are important natural enemies because they can feed on plant-provided pollen and several prey species, and thus persist in crops even in the absence of the target pest. Hence, populations of these predators can be established in a crop by providing alternative food, thus increasing biological control. We investigated how alternative food affects broad mite (Polyphagotarsonemus latus) control on chilli pepper plants by predatory mites. The predatory mite Amblyseius herbicolus had high oviposition and population growth rates when fed with cattail pollen, chilli pepper pollen and bee-collected pollen, and a low rate on the alternative prey Tetranychus urticae. Supplementing pepper plants with pollen resulted in better control of broad mite populations. Release of A. herbicolus on young plants with weekly addition of honeybee pollen until plants produce flowers seems a viable strategy to sustain populations of this predator, thus protecting young, vulnerable plants from broad mite infestations. © 2015 The Author(s)

Rezende M.Q.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Perez A.L.,Federal University of Viçosa | Cardoso I.M.,Federal University of Viçosa | Janssen A.,University of Amsterdam
Agriculture, Ecosystems and Environment | Year: 2014

Plant diversity may increase natural enemy populations because some plants can provide alternative food to natural enemies. Extrafloral nectar is such an alternative food and plants producing extrafloral nectar are known to suffer less from herbivory. Little is known about the effect of plants with extrafloral nectaries on herbivory of neighbouring plants. Here, we investigated whether extrafloral nectaries of an associated tree (Inga subnuda subsp. luschnathiana) can enhance natural pest control in coffee agroforestry systems. We assessed the effect of nectar availability from Inga trees on parasitism of coffee leaf miners (Leucoptera coffeella) and on damage caused by coffee leaf miners and coffee berry borers (Hypothenemus hampei). Most of the nectary visitors were either parasitoids or predators, with most predators being natural enemies of coffee pests. Coffee plants were sampled every metre along a transect of 10-15. m extending from each Inga tree. The distance of the coffee plants from the Inga trees did not significantly correlate with coffee leaf miner parasitism, proportion of mined leaves or with the proportion of bored coffee berries. We subsequently used abundance and species richness of those nectary visitors without known association with leaf miners and borers as indirect measures of nectar availability. Whereas species richness had no significant effect on natural pest control, leaf miner parasitism increased significantly with the abundance of nectary visitors (excluding natural enemies of the coffee pests), and the proportion of mined leaves decreased significantly with this abundance. The proportion of bored fruits decreased with increasing abundance of visitors, but this trend was not significant. Together, these results suggest that Inga trees provide alternative food to natural enemies of coffee pests, resulting in increased natural control. Thus, extrafloral nectaries of associated trees can enhance natural pest control in agroforestry systems. © 2014 Elsevier B.V.

Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Oliveira R.M.,Federal University of Viçosa | Perez A.L.,Federal University of Viçosa | Rodriguez-Cruz F.A.,Federal University of Viçosa | Martins Filho S.,Federal University of Viçosa
Pest Management Science | Year: 2013

Background: An acaricidal effect of lime sulfur has not been demonstrated for Polyphagotarsonemus latus. However, lime sulfur can cause toxicity to natural enemies and to host plants. In this study, the toxicity of different concentrations of lime sulfur to P. latus, to the predatory mite Amblyseius herbicolus and to the predatory insect Chrysoperla externa was evaluated. Additionally, the phytotoxicity of lime sulfur to two P. latus hosts, chili pepper and physic nut plants, was determined. Results: Lime sulfur at a concentration of 9.5 mL L-1 restrained P. latus population growth. However, this concentration was deleterious to natural enemies. The predatory mite A. herbicolus showed a negative value of instantaneous growth rate, and only 50% of the tested larvae of C. externa reached adulthood when exposed to 10 mL L-1. Physic nut had severe injury symptoms when sprayed with all tested lime sulfur concentrations. For chili pepper plants, no phytoxicity was observed at any tested concentration. Conclusion: Lime sulfur might be used for P. latus control on chili pepper but not on physic nut owing to phytotoxicity. Care should be taken when using lime sulfur in view of negative effects on natural enemies. Selective lime sulfur concentration integrated with other management tactics may provide an effective and sustainable P. latus control on chili pepper. © 2012 Society of Chemical Industry.

Marques R.V.,Federal University of Tocantins | Sarmento R.A.,Federal University of Tocantins | Lemos F.,Federal University of Viçosa | Lemos F.,University of Amsterdam | And 5 more authors.
Functional Ecology | Year: 2015

Mixing of prey that differ in nutrient content or toxic compounds (dietary mixing) may allow synovigenic predatory arthropods to balance their diet or dilute toxins of different prey items to maximize performance: dietary mixing may therefore explain the prevalence of polyphagy in this functional group. Several predatory arthropods can redress nutritional imbalances in their diet by actively mixing different diets, based on experiments with artificial diets or with prey that were manipulated to contain different nutrients. Evidence is also accumulating that predator species perform better on a mixed diet of several different prey species, but evidence that they actively forage for different prey species is scarce. Thus, evidence that predators actively forage for a mixed diet consisting of natural, non-manipulated prey to increase their performance is still rare. Here, we investigate whether arthropod predators invest in achieving an optimal diet by active mixing of different prey species or by simply eating what they encounter. Females of two species of plant-inhabiting predatory mites produced significantly more eggs when feeding on a prey mixture of co-occurring phytophagous mites than when feeding on either of the two prey species separately. When the two prey species were offered on two separate, connected patches at some distance from each other, predators commuted significantly more between the two patches to obtain a mixed diet and had a significantly increased egg production than predators that were offered a single prey species on two patches. Thus, predators actively commuted between patches to balance their diet. We propose that active dietary mixing can have synergistic effects on predator fitness and has the potential to explain polyphagy in this functional group. © 2015 British Ecological Society.

Amaral D.S.S.L.,Federal University of Viçosa | Venzon M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Duarte M.V.A.,Federal University of Viçosa | Duarte M.V.A.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | And 4 more authors.
Biological Control | Year: 2013

Habitat manipulation has long been used as strategy to enhance beneficial insects in agroecosystems. Non-crop weed strips have the potential of supplying food resources to natural enemies, even when pest densities are low. However, in tropical agroecosystems there is a paucity of information pertaining to the resources provided by non-crop weeds and their interactions with natural enemies. In this study we evaluated (a) whether weeds within chili pepper fields affect the diversity and abundance of aphidophagous species; (b) whether there are direct interactions between weeds and aphidophagous arthropods; and (c) the importance of weed floral resources for survival of a native and exotic coccinellid in chili pepper agroecosystems. In the field, aphidophagous arthropods were dominated by Coccinellidae, Syrphidae, Anthocoridae, Neuroptera and Araneae, and these natural enemies were readily observed preying on aphids, feeding on flowers or extrafloral nectaries, and using plant structures for oviposition and/or protection. Survival of native Cycloneda sanguinea (Coleoptera: Coccinellidae) differed between plant species, with significantly greater survival on Ageratum conyzoides and Bidens pilosa. However, no evidence was gathered to suggest that weed floral resources provided any nutritional benefit to the exotic Harmonia axyridis (Coleoptera: Coccinellidae). This research has provided evidence that naturally growing weeds in chili pepper agroecosystems can affect aphid natural enemy abundance and survival, highlighting the need for further research to fully characterize the structure and function of plant resources in these and other tropical agroecosystems. © 2012 Elsevier Inc.

dos Santos S.R.,State University of Montes Claros | Kondo M.K.,State University of Montes Claros | de Oliveira P.M.,Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG | Junior I.O.A.,State University of Montes Claros | de Matos A.T.,Federal University of Viçosa
Australian Journal of Crop Science | Year: 2015

Irrigation with wastewater is an agricultural practice used to supply plants with nutrients that can reduce the nutrient load impact on fresh water sources and save conventional water sources. However, the physical and chemical properties of soil can be altered according to specific wastewater characteristics. This study aimed to investigate short-term changes in soil physical and chemical properties after irrigation of cotton with preliminary treated wastewater (PTW) and tertiary treated wastewater (TTW) as potassium sources in the semi-arid region of Minas Gerais State, Brazil. A randomized complete block design (RCBD) with four replications and five treatments was used: a combination of two wastewaters (PTW and TTW) as potassium topdressing sources and two equivalent doses to 40 and 60 kg K2O ha-1, as well as a control treatment with a conventional mineral fertilizer. After the first soil sampling, the liming, NPK fertilizer, urea and potassium chloride treatments increased the base saturation and electrical conductivity up to 0.4 m soil depth. Wastewater potassium sources did not promote chemical excesses in the four soil depths evaluated, although the sodium content increased up to 0.6 m depth with 60 kg K2O ha-1 via TTW. The same dose (60 kg K2O ha-1) via PTW decreased the soil pH in the top 0.2 m and the water-dispersible clay (WDC) level up to 0.6 m depth due to the better chemical balance of this wastewater. In general, it is recommended to use PTW when providing 60 kg K2O ha-1 in topdressing.

Loading Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG collaborators
Loading Agriculture and Livestock Research Enterprise of Minas Gerais EPAMIG collaborators