Population dynamics of the pasture leafhopper complex (Hemiptera: Cercopidae) in brachiaria and mombasa grass

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Westefann Dos Santos Sousa ◽  
Jorge Luis Carvalho Silva ◽  
Thiago Souza Campos ◽  
João Victor De Lima Santos
Keyword(s):  
Population Dynamics ◽  
Meteorological Data ◽  
Insect Pest ◽  
Climatic Conditions ◽  
Panicum Maximum ◽  
Brachiaria Decumbens ◽  
Widespread Occurrence ◽  
Observation Area ◽  
Pasture Degradation ◽  
Forage Species

Pasture leafhoppers are considered highly important pests in forage grasses in Brazil due to their widespread occurrence. This insect is one of the most relevant pests in pasture degradation. In order for the control of spittlebugs to be efficient, it is important to know the population behavior of the species of this insect, identify the period of greatest occurrence, as well as the climatic and environmental conditions that favor the development of the pest. Thus, this study aimed to evaluate the population dynamics of spittlebugs, at a quantitative level, in Brachiaria decumbens and Panicum maximum pastures, associating the results with meteorological data from the municipality of Conceição do Araguaia, Southeast Pará. To study the population dynamics of spittlebugs, samples were taken every two weeks, in two types of pastures aged between 5 and 7 years, kept under rotational grazing, with a stocking of 1.5 animal units. The method of monitoring nymphs and adults of leafhoppers was adopted, through walking within the observation area. The level of infestation of spittlebugs in both forage species was evaluated and all results were submitted to analysis of variance by the F test. It was found that the species B. decumbens had a greater number of adults and nymphs when compared to the forage species P. maximum. The population dynamics of spittlebugs occur gradually according to climatic conditions, and the period with not-so-high temperatures (22 ºC to 34 ºC) and good rainfall provide an infestation of this insect pest in the pasture.

scholarly journals Chemical control of signalgrass for establishing Tanzania-grass

2020 ◽  
Vol 42 ◽  
pp. e48408
Author(s):  
Barbara Martins Rodrigues ◽  
Marcia Vitoria Santos ◽  
Josimari Regina Paschoaloto ◽  
Thiago Gomes dos Santos Braz ◽  
José Barbosa Santos ◽  
...  
Keyword(s):  
Chemical Control ◽  
Panicum Maximum ◽  
Herbicide Application ◽  
Brachiaria Decumbens ◽  
Forage Species ◽  
Efficient Control ◽  
Guinea Grass

Herbicides have been used to control Brachiaria grass in pastures established or in formation given their practicality, however their efficiency is questionable due to the lack of specific graminicides for different forage species. Therefore, the goal of this study was to evaluate the efficiency of glyphosate and fluazifop-p-butyl in the control of Brachiaria decumbens (signalgrass) and the intoxication levels of Panicum maximum cv. Tanzania (Tanzania quinea grass) in pasture establishment. The experiments were designed in randomized blocks, in a 2 × 5 × 4 factorial arrangement of two herbicides (fluazifop-p-butyl and glyphosate), five doses equivalent to the commercial dosage of each herbicide (0.25; 0.50; 1.00; 1.50; 200), and four evaluation times after herbicide application (15, 21, 30 and 45 days). There was interaction between doses and evaluation times. The dose 1.5 L ha-1 fluazifop-p-butyl provides efficient control of signalgrass, however, leads to high intoxication in Tanzania guinea grass. Glyphosate is efficient in the control of signalgrass even at the lowest dose (90 g ha-1), however, it causes high intoxication in Tanzania guinea grass, preventing its use in developing pastures. It can be concluded that fluazifop-p-butyl and glyphosate herbicides are not recommended for the control of B. decumbens, cv. Basilisk in developing pastures of Tanzania guinea grass.

DROUGHT OCCURRENCE UNDER LITHUANIAN CLIMATIC CONDITIONS

2015 ◽  
Author(s):  
Laima TAPARAUSKIENĖ ◽  
Veronika LUKŠEVIČIŪTĖ
Keyword(s):  
Meteorological Data ◽  
Standardized Precipitation Index ◽  
Vegetation Period ◽  
Climatic Conditions ◽  
Precipitation Record ◽  
Calculation Step ◽  
Drought Conditions ◽  
The Standardized Precipitation Index ◽  
June July

This study provides the analysis of drought conditions of vegetation period in 1982-2014 year in two Lithuanian regions: Kaunas and Telšiai. To identify drought conditions the Standardized Precipitation Index (SPI) was applied. SPI was calculated using the long-term precipitation record of 1982–2014 with in-situ meteorological data. Calculation step of SPI was taken 1 month considering only vegetation period (May, June, July, August, September). The purpose of investigation was to evaluate the humidity/aridity of vegetation period and find out the probability of droughts occurrence under Lithuanian climatic conditions. It was found out that according SPI results droughts occurred in 14.5 % of all months in Kaunas region and in 15.8 % in Telšiai region. Wet periods in Kaunas region occurred in 15.8 %, and in Telšiai region occurrence of wet periods was – 18.8 % from all evaluated months. According SPI evaluation near normal were 69.7 % of total months during period of investigation in Kaunas and respectively – 65.5 % in Telšiai. The probability for extremely dry period under Lithuania climatic conditions are pretty low – 3.0 % in middle Lithuania and 2.4 % in western part of Lithuania.

A METHOD FOR REARING THE LARVAL STAGES OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE), FOR PHYSIOLOGICAL STUDIES

1990 ◽  
Vol 122 (6) ◽  
pp. 1271-1272 ◽  
Author(s):  
Hemendra Mulye ◽  
Roger Gordon
Keyword(s):  
Population Dynamics ◽  
North America ◽  
Choristoneura Fumiferana ◽  
Insect Pest ◽  
Spruce Budworm ◽  
Forest Pest ◽  
Forest Insect ◽  
Larval Stages ◽  
Eastern Spruce Budworm ◽  
Physiological Studies

The eastern spruce budworm, Choristoneura fumiferana Clemens, is the most widely distributed and destructive forest insect pest in North America. Although much is known about the ecology, population dynamics, and impact of C. fumiferana on tree growth (Sanders et al. 1985), there is very little information available on the physiology of this forest pest. Physiological studies are crucial to the development of novel strategies for spruce budworm control.

scholarly journals Controle de dez espécies daninhas em cana-de-açúcar com o herbicida mesotrione em mistura com ametryn e metribuzin

2010 ◽  
Vol 28 (3) ◽  
pp. 585-590 ◽  
Author(s):  
F.T. Carvalho ◽  
R.M. Castro ◽  
R.I. Otsubo ◽  
F.A.R. Pereira
Keyword(s):  
Panicum Maximum ◽  
Bidens Pilosa ◽  
Brachiaria Decumbens ◽  
Ipomoea Nil

Existem muitas opções de herbicidas para aplicações em pré-emergência em cana-de-açúcar, mas o grande desafio atual para a cultura é o controle pós-emergente. O objetivo deste trabalho foi avaliar a eficácia do herbicida mesotrione em mistura com ametryn e metribuzin no controle em pós-emergência de 10 espécies daninhas semeadas em cana-de-açúcar, variedade RB 86-7515. As espécies daninhas selecionadas para o experimento foram: Brachiaria decumbens, Brachiaria plantaginea, Cenchrus echinatus, Digitaria horizontalis, Panicum maximum, Amaranthus deflexus, Bidens pilosa, Euphorbia heterophylla, Ipomoea nil e Sida glaziovii, semeadas nas entrelinhas após a emergência da cultura. Os herbicidas foram aplicados aos 45 dias após o plantio da cana-de-açúcar, com as plantas daninhas monocotiledôneas na fase de terceiro perfilho e as dicotiledôneas com três a quatro pares de folhas, e constaram dos seguintes tratamentos: mesotrione (120 g ha-1); ametryn (2.000 g ha-1); metribuzin (1.920 g ha-1); mesotrione + ametryn (120 g + 2.000 g ha-1); mesotrione + metribuzin (120 g + 1920 g ha-1) e testemunhas no mato e no limpo. Concluiu-se que os herbicidas isolados ou em mistura foram seletivos à cana-de-açúcar. Com relação à eficácia, observou-se que o herbicida mesotrione foi eficiente no controle de A. deflexus; ametryn, no controle de A. deflexus, B. pilosa e I. nil; metribuzin, no controle de A. deflexus, B. pilosa e S. glaziovii; mesotrione + ametryn, no controle de B. decumbens, B. plantaginea, D. horizontalis, P. maximum, A. deflexus, B. pilosa, I. nil e S. glaziovii; e mesotrione + metribuzin, no controle de B. plantaginea, D. horizontalis, P. maximum, A. deflexus, B. pilosa e S. glaziovii. Foi constatado elevado efeito sinergístico do mesotrione com os herbicidas testados, sendo o efeito mais pronunciado na mistura com o ametryn.

scholarly journals A modelling study of the event-based retention performance of green roof under the hot-humid tropical climate in Kuching

2017 ◽  
Vol 76 (11) ◽  
pp. 2988-2999 ◽  
Author(s):  
C. T. Chai ◽  
F. J. Putuhena ◽  
O. S. Selaman
Keyword(s):  
Flash Flood ◽  
Retention Rate ◽  
Meteorological Data ◽  
Green Roof ◽  
Tropical Climate ◽  
Climatic Conditions ◽  
Retention Performance ◽  
Strong Negative Correlation ◽  
Rainfall Depth ◽  
Event Based

Abstract The influences of climate on the retention capability of green roof have been widely discussed in existing literature. However, knowledge on how the retention capability of green roof is affected by the tropical climate is limited. This paper highlights the retention performance of the green roof situated in Kuching under hot-humid tropical climatic conditions. Using the green roof water balance modelling approach, this study simulated the hourly runoff generated from a virtual green roof from November 2012 to October 2013 based on past meteorological data. The result showed that the overall retention performance was satisfactory with a mean retention rate of 72.5% from 380 analysed rainfall events but reduced to 12.0% only for the events that potentially trigger the occurrence of flash flood. By performing the Spearman rank's correlation analysis, it was found that the rainfall depth and mean rainfall intensity, individually, had a strong negative correlation with event retention rate, suggesting that the retention rate increases with decreased rainfall depth. The expected direct relationship between retention rate and antecedent dry weather period was found to be event size dependent.

scholarly journals Analysis of evapotranspiration and biomass in pastures with degradation indicatives in the Upper Tocantins River Basin, in Brazilian Savanna

Revista CERES ◽  
2016 ◽  
Vol 63 (6) ◽  
pp. 754-760 ◽  
Author(s):  
Ricardo Guimarães Andrade ◽  
Antônio Heriberto de Castro Teixeira ◽  
Janice Freitas Leivas ◽  
Sandra Furlan Nogueira
Keyword(s):  
River Basin ◽  
Large Scale ◽  
Meteorological Data ◽  
Simple Algorithm ◽  
Production Potential ◽  
Pasture Degradation ◽  
Ndvi Time Series ◽  
Tocantins River ◽  
Remote Sensing Techniques ◽  
Degraded Pastures

ABSTRACT The objective of this study was to apply the Simple Algorithm For Evapotranspiration Retrieving (SAFER) with MODIS images together with meteorological data to analyze evapotranspiration (ET) and biomass production (BIO) according to indicative classes of pasture degradation in Upper Tocantins River Basin. Indicative classes of degraded pastures were obtained from the NDVI time-series (2002-2012). To estimate ET and BIO in each class, MODIS images and data from meteorological stations of the year 2012 were used. The results show that compared to not-degraded pastures, ET and BIO were different in pastures with moderate to strong degradation, mainly during water stress period. Therefore, changes in energy balance partition may occur according to the degradation levels, considering that those indicatives of degradation processes were identified in 24% of the planted pasture areas. In this context, ET and BIO estimates using remote sensing techniques can be a reliable indicator of forage availability, and large-scale aspects related to the degradation of pastures. It is expected that this knowledge may contribute to initiatives of public policies aimed at controlling the loss of production potential of pasture areas in the Upper Tocantins River Basin in the state of Goiás, Brazil.

scholarly journals Intoxicações por plantas em ruminantes e equídeos na região central de Rondônia

2012 ◽  
Vol 42 (7) ◽  
pp. 1257-1263 ◽  
Author(s):  
Sandro Vargas Schons ◽  
Tiago Vaz Lopes ◽  
Taciane Leticia de Melo ◽  
João Padovani Lima ◽  
Franklin Riet-Correa ◽  
...  
Keyword(s):  
Manihot Esculenta ◽  
Panicum Maximum ◽  
Brachiaria Brizantha ◽  
Brachiaria Decumbens ◽  
Em 12

Foi realizado um levantamento em 12 municípios da região central de Rondônia sobre a presença de plantas tóxicas e ocorrência de surtos de intoxicação em ruminantes e equídeos. O trabalho foi desenvolvido mediante a utilização de um questionário aplicado a médicos veterinários, agrônomos, zootecnistas e produtores rurais, com o objetivo de identificar as principais plantas tóxicas que ocorrem na região. Trinta e quatro entrevistados relataram casos de intoxicação por uma ou mais plantas comprovadamente tóxicas como: Palicourea marcgravii (12 surtos), Palicourea grandiflora e Enterolobium contortisiliquum (sete surtos cada) e Palicourea juruana, Brachiaria radicans, Brachiaria brizantha e Manihot esculenta (dois surtos cada). Em ovinos, foram relatados dois surtos de fotossensiblização por Brachiaria decumbens e um surto de mortalidade por Palicourea grandiflora. Dos 34 surtos relatados em bovinos pelos entrevistados, 374 (8,9%) animais foram afetados e 311 (7,4%) morreram, de um total de 4.192 de ambos os sexos sob risco. De um total de 250 ovinos sob risco, três surtos de intoxicação por plantas foram relatados e afetaram 28 animais, dos quais 20 morreram. Amorimia sp., previamente desconhecida como tóxica, foi identificada como causa de morte súbita em 32% das propriedades. Quinze surtos de cólica em equídeos que pastavam cultivares de Panicum maximum ('Massai', 'Tanzânia' e 'Mombaça') durante o período das chuvas foram, também, observados. Os resultados do presente trabalho demonstram a importância significativa das intoxicações por plantas como causa de perdas econômicas para a pecuária da região central do Estado de Rondônia. Com a realização deste trabalho, o número de plantas tóxicas para ruminantes com a confirmação de ocorrência de surtos com mortalidade na região passou de um para nove, o que confirma que um trabalho sistemático de investigação é necessário para o conhecimento da importância das intoxicações por plantas na região Norte do Brasil.

scholarly journals Allocative efficiency and adoption of improved maize variety: A case of eastern hills of Nepal

2020 ◽  
Vol 3 (1) ◽  
pp. 148-159
Author(s):  
Tilak Katel ◽  
Bhishma Raj Dahal ◽  
Sandesh Bhatta
Keyword(s):  
Regression Model ◽  
Insect Pest ◽  
Allocative Efficiency ◽  
Climatic Conditions ◽  
Probit Regression ◽  
Maize Production ◽  
Factors Affecting ◽  
Face To Face ◽  
Maize Variety ◽  
Structured Questionnaire

Production and  profit from maize farming can be substantially increased by allocating resources efficiently and adopting improved maize variety. In this context, a study was undertaken to determine the allocative efficiency and factors affecting adoption of improved maize variety in Eastern hills of Nepal. Random sampling was conducted in eastern part of Khotang district namely, Halesi municipality and Diktel Rupakot Majuwagadi municipality during month of March 2019. Pretested semi-structured questionnaire was administered among 80 randomly selected farmers cultivating maize since last two years. Face to face interview was scheduled to obtain data. Cobb Douglas production function was used to determine allocative efficiency; probit regression model was launched to determine factors affecting adoption of improved maize variety.  Significant positive relation of cost of seed, planting, and weeding with income has suggested to increase expenditure on certified maize seed over own farm seed, line sowing over broadcasting, and weeding. The model revealed that increasing all the factors of production by 100% would result in increase in income by 71.83%. Furthermore, cultivating improved maize variety is more profitable than own farm seed. Probit regression model showed that, farmers who have received training, who were member of cooperatives and who have received high schooling were more likely to adopt open-pollinated improved maize variety. Unavailability of inputs (seed, fertilizer, and labor), insect pest attack and adverse climatic conditions were major constraint of maize farming. Therefore, it would be better to suggest maize producers to increase expenditure on seed; make maize field weed free and adopt line sowing method. In addition, providing training, increasing access over inputs and encouraging farmers towards cooperatives could be virtuous for sustainable maize production.

scholarly journals Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

2012 ◽  
Vol 21 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Raquel Abdallah da Rocha ◽  
Patrizia Ana Bricarello ◽  
Gilberto Pedroso da Rocha ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Dry Matter ◽  
Cynodon Dactylon ◽  
Larval Survival ◽  
Grass Species ◽  
Panicum Maximum ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Brachiaria Decumbens ◽  
Infective Larvae ◽  
Experimental Plots

This experiment aimed to assess the recovery of infective larvae (L3) of Trichostrongylus colubriformis from Brachiaria decumbens cv. Australiana, Cynodon dactylon cv. Coast-cross and Panicum maximum cv. Aruana. The experimental module comprised six plots, with two plots per herbage species. Larval survival was assessed from autumn to winter, under the effect of two herbage-paring heights (5 and 30 cm). TThe paring was carried out immediately before contamination with faces containing T. colubriformis eggs. The feces and herbage were collected at one, two, four, eight, 12 and 16 weeks after feces had been deposited in the experimental plots. In general, larvae were recovered from both herbage and feces until the 16th week. The longer persistence of these larvae in the environment was probably due to warmer temperatures. The number of L3 recovered from the pasture was not influenced by the height of plants, except for Brachiaria and Aruana herbage in the fourth week. Regarding the concentrations of larvae per kg of dry matter (L3/kg DM), recovery was higher from low pasture in all three herbage species. During the autumn, the development and survival of the T. colubriformis free-living stages were not affected by the different herbage species.

scholarly journals S-metolachlor efficacy on the control of Brachiaria decumbens, Digitaria horizontalis, and Panicum maximum in mechanically green harvested sugarcane

2012 ◽  
Vol 30 (4) ◽  
pp. 861-870 ◽  
Author(s):  
N.M. Correia ◽  
F.J. Perussi ◽  
L.J.P. Gomes
Keyword(s):  
Sugar Cane ◽  
Crop Residue ◽  
Block Design ◽  
Soil Surface ◽  
Panicum Maximum ◽  
Herbicide Application ◽  
Visible Injury ◽  
Brachiaria Decumbens ◽  
Randomized Complete Block Design ◽  
Herbicide Treatments

The aim of this study was to assess the efficacy of S-metolachlor applied in pre-emergence conditions for the control of Brachiaria decumbens, Digitaria horizontalis, and Panicum maximum in sugar cane mechanically harvested without previous burning of the crop (green harvest) with the crop residue either left or not on the soil surface. The experiments were established in the field according to a randomized complete block design with four repetitions in a 7 x 2 split-plot scheme. In the plots, five herbicide treatments were studied (S-metolachlor at 1.44, 1.92, and 2.40 kg ha-1, clomazone at 1.20 kg ha-1, and isoxaflutole at 0.188 kg ha-1), and two control treatments with no herbicide application. In the subplots, the presence or absence of sugar cane crop residue on the soil surface was evaluated. S-metolachlor efficacy was not hampered by either 14 or 20 t ha-1 of sugar cane crop residue on the soil surface. When sugar cane crop residue was covering the soil surface, S-metolachlor at a rate of 1.44 kg ha-1 resulted in weed control similar at their larger rates, where as without the presence of crop residue, S-metolachlor controlled B. decumbens, D. horizontalis, and P. maximum at the rates of 1.92, 1.44, and 1.92 kg ha-1, respectively. The herbicides clomazone and isoxaflutole were effective for the studied species, independently of the crop residue covering the soil surface. S-metolachlor caused no visible injury symptoms to the sugar cane plant. Clomazone and isoxaflutole caused visible injuries to the sugar cane plant. None of the herbicides negatively affected the number of viable culms m² or the culm height and diameter.

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