Epidemiological factors influencing the success of roguing for the control of bunchy top disease of bananas in New South Wales

1978 ◽  
Vol 29 (3) ◽  
pp. 535 ◽  
Author(s):  
RN Allen
Keyword(s):  
Incubation Period ◽  
Infection Rate ◽  
Detection Efficiency ◽  
Late Summer ◽  
Disease Symptoms ◽  
Factors Influencing ◽  
South Wales ◽  
Number Of Leaves ◽  
Time Of Year ◽  
Banana Leaves

An infection chain was reconstructed from historical data of a typical outbreak of bunchy top disease of bananas to determine factors influencing the seasonal occurrence and eradication of disease under roguing. The results were described by a mathematical model involving four random variables (incubation period, relative infection rate, detection efficiency and eradication efficiency) and one fixed variable (inspection interval). The model successfully predicted the course of roguing in an independent disease outbreak. The incubation period of the disease depended on the time taken for two banana leaves to emerge after inoculation. At Alstonville, N.S.W., the incubation period varied from 19 days in summer to 125 days in winter. The relative infection rate varied on average from 0.027 to 0.001 new infections per old infection per day in summer and winter respectively. Efficiency of disease detection by experienced inspectors depended on the number of leaves displaying disease symptoms and, equally, on time of year. Under the normal 3-weekly inspection routine, detection efficiency varied from 0.94 in summer to 0.19 in winter, plants being found on average at the two-leaf stage of disease. The efficiency with which banana growers eradicated diseased plants following their detection was found to be a characteristic of the grower concerned but was, in general, poorest in late summer.

scholarly journals POTENSI AGENSIA HAYATI DAN NABATI DALAM MENGENDALIKAN PENYAKIT BUSUK RIMPANG JAHE

2005 ◽  
Vol 5 (1) ◽  
pp. 50-57
Author(s):  
Loekas Soesanto ◽  
Sudarmono Sudarmono ◽  
Nur Prihatiningsih ◽  
Abdul Manan ◽  
Endang Iriani ◽  
...  
Keyword(s):  
Incubation Period ◽  
Infection Rate ◽  
Trichoderma Harzianum ◽  
Block Design ◽  
Central Java ◽  
Randomized Block Design ◽  
Ginger Rhizome ◽  
Number Of Leaves ◽  
Central Java Province ◽  
Rhizome Rot

Potency of biological and botanical agents in controlling ginger rhizome rot. Research aimed at knowing integrity of various control agents in controlling causal agent of ginger rhizome rot. The research was carried out at Gowak Village, Pringsurat District, Temanggung Regency, Central Java Province, from November up to May 2004. Randomized Block Design was used with treatments of biological (Bacillus sp. with density of x  1010 cfu ml-1 suspension and Trichoderma harzianum 20 g crop-1), of botanical (clove leaves powder of 20 g crop-1 and neem seeds extract of 25 ml crop-1), and synthetical agents (benomil with concentration of 2 g l-1) either alone or in combination, with three replicates. Variables observed were incubation period, disease intensity, infection rate, number of leaves per crop, crop height, and ginger production per hectare. Result of the research showed that the location was endemic of the disease. The treatments could generally retard the incubation period and the infection rate, decrease the disease intensity, and increase the ginger production. The highest ginger yield was obtained from the plot given Trichoderma harzianum (Trikonis), either alone or in combination with the dry clove leaves of 10 g crop-1 as many as four times with interval of seven days started from seedling planted.

scholarly journals Pengendalian Penyakit Pustul Xanthomonas axonopodis pv. glycines Pada Kedelai Dengan Bacillus spp. Asal Filosfer Gulma di Pertanaman Kedelai

2020 ◽  
Vol 2 (2) ◽  
pp. 53
Author(s):  
Siti Rahayu ◽  
Suhartiningsih Dwi Nurcahyanti
Keyword(s):  
Incubation Period ◽  
Infection Rate ◽  
Soybean Plant ◽  
Xanthomonas Axonopodis ◽  
Severity Of Disease ◽  
Bacillus Spp ◽  
Number Of Leaves ◽  
Treatment Application ◽  
Number Of Branches

Soybean pustule disease by Xanthomonas axonopodis pv. glycines (Xag) is one of the important diseases of soybean plant. Application Bacillus spp. origin of weed phyllosphere has a great potential as an alternative to control because it is isolated to origin of same region as Xag is the phyllosphere. Research by Nurcahyanti and Ayu obtained the best five isolates of Bacillus spp. of weeds phyllosphere in soybean cropping in inhibiting Xag in vitro. This study used the complete random draft (RAL) 6 treatment, 4 repeats, each unit consists of 4 plants wich treatment application of 5 isolates of Bacillus spp. namely K = control; A = Bacillus JG 1.3; B = Bacillus JG 3.6; C = Bacillus JG 1.4.1; D = Bacillus BGd 1.1; E = Bacillus Bp 2.2. The results showed that application of Bacillus spp. could inhibit Xag in vitro with bacteriostatic mechanism and isolates Bacillus BGd 1.1 has the greatest inhibition of 14.25 mm. Fifth Bacillus spp. can suppress the development of disease and isolates Bacillus BGd 1.1 has best results with the incubation period during 13 HSI, the severity of disease 10.07%, infection rate 0.045 unit/day as well as the effectiveness of control 85.72%. The fifth isolates of Bacillus spp. can not increase the number of leaves but can increase number of branches and isolates Bacillus JG 1.3, Bacillus JG 1.4.1 and Bacillus BGd 1.1 can increase the height of soybean crop.

Factors influencing the occurrence of high ultimate pH in three muscles of lamb carcasses in Australia

2014 ◽  
Vol 54 (10) ◽  
pp. 1853 ◽  
Author(s):  
N. G. McPhail ◽  
J. L. Stark ◽  
A. J. Ball ◽  
R. D. Warner
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Rectus Femoris ◽  
Carcass Weight ◽  
Mixed Model Analysis ◽  
Factors Influencing ◽  
South Wales ◽  
Generalised Linear Mixed Model ◽  
Processing Plants ◽  
Few Data

Chilled lamb meat exported from Australia has, on occasions, been rejected by importing countries due to greening, after only 6 weeks of storage time. Greening is known to be more prevalent in high ultimate pH (pHu) beef meat (>5.9). There are few data available for lamb carcasses in Australia on the occurrence of high pHu meat, which may have an impact on the understanding and control of quality and greening during storage. The aim of this project was to determine the prevalence of, and influencing factors for, high pHu meat in a range of muscle types in lamb carcasses in Australia. Muscle pHu data were collected from a total of 1614 carcasses from 78 lots at four lamb processing plants in Victoria and New South Wales in autumn and spring of 2013. The pHu of the knuckle (rectus femoris), rack (longissimus) and blade (infraspinatus) was measured and data on carcass and lot characteristics were recorded. Data were subjected to restricted maximum likelihood and generalised linear mixed model analysis. The mean pHu of the knuckle, rack and shoulder were 6.06, 5.79 and 6.12 respectively, and the main factors influencing muscle pHu and occurrence of dark-cutting were breed, season, electrical stimulation and carcass weight. Merino lambs had a higher pHu in the blade and knuckle than did other breeds (P < 0.05, P < 0.01 respectively). Lambs processed in autumn had a higher predicted pHu in the blade and knuckle and a higher percentage dark-cutting (DC; pHu >6.0) for those muscles, than did those processed in spring (P < 0.05). Carcasses that had been electrically stimulated had a higher %DC and a higher pHu in all three muscles (P < 0.05). Carcass weight had a significant effect on the pHu of all three muscles (P < 0.001), with heavier carcasses having a lower pHu and lower %DC. The pHu of the rack was not a reliable predictor for the pHu in other muscles of the lamb carcass. In conclusion, the high occurrence of DC in the muscles, particularly the blade and knuckle, suggests that these muscles may be at risk for producing greening in the vacuum bag during storage.

Impact of extrafloral nectar availability and plant genotype on ant (Hymenoptera: Formicidae) visitation to quaking aspen (Salicaceae)

2015 ◽  
Vol 148 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Jonathon R. Newman ◽  
Diane Wagner ◽  
Patricia Doak
Keyword(s):  
Populus Tremuloides ◽  
Late Summer ◽  
Early Summer ◽  
Quaking Aspen ◽  
Plant Genotype ◽  
Free Living ◽  
Natural Induction ◽  
Formica Fusca ◽  
Time Of Year ◽  
Nectar Availability

AbstractFor quaking aspen (Populus tremuloides Michaux; Salicaceae) the rate of extrafloral (EF) sugar secretion is increased by defoliation and decreased by drought. Although wholesale blocking of EF nectar has been shown to reduce ant (Hymenoptera: Formicidae) visitation to aspen, the effect of more subtle and realistic variations in nectar availability on ant recruitment is unknown. Working in Alaskan boreal forest (United States of America), we reduced and supplemented EF nectar availability on potted aspen ramets of three genotypes and surveyed visitation by free-living Formica fusca (Linnaeus) (Hymenoptera: Formicidae). Ants were more responsive to a subtle increase in sugar availability than to a decrease. While nectar reduction had no effect on ant visitation, nectar supplementation increased ant visitation to one aspen genotype by 70% during an early summer trial. Average ant visitation to different aspen genotypes varied during the late summer, indicating that aspen genotype can influence attractiveness to ants. We conclude that natural induction of EF secretion in response to herbivory may benefit aspen through improved ant recruitment, though the response is dependent on aspen genotype and time of year. Differences among aspen genets in attractiveness to ants could influence the relative success of genotypes, especially in settings in which aspen regenerates from seed.

scholarly journals Fish nursery value of algae habitats in temperate coastal reefs

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6797 ◽  
Author(s):  
Hilmar Hinz ◽  
Olga Reñones ◽  
Adam Gouraguine ◽  
Andrew F. Johnson ◽  
Joan Moranta
Keyword(s):  
Juvenile Fish ◽  
Strong Association ◽  
Late Summer ◽  
Early Spring ◽  
Rocky Reef ◽  
Term Survival ◽  
Fish Nursery ◽  
Prey Biomass ◽  
Reduced Height ◽  
Time Of Year

The nursery function of coastal habitats is one of the most frequently mentioned and recognized ecosystem services in the valuation of coastal ecosystems. Despite its importance our understanding of the precise habitat parameters and mechanisms that make a habitat important as a nursery area is still limited for many species. The study aimed to establish the importance of different algae morphotypes in providing shelter and food for juvenile coastal fish during the main settlement peaks, in early spring and late summer, in littoral rocky reef systems in the Northwestern Mediterranean. The results of our study showed strong seasonal differences in algae cover, composition and height between the two sampling periods. Overall, during spring the algae were well developed, while in late summer, both density and height, of most algae decreased considerably. Equally, prey biomass, in form of suitable sized invertebrate fauna associated to the algae, decreased. Accordingly, the shelter and food for the fish settling in this habitat during late summer were less abundant, indicating a mismatch between the observed presence of juvenile fish and optimal habitat conditions. Differences in prey densities were detected between algae morphotypes, with structurally more complex algae, such as Cystoseira spp. and Halopteris spp. consistently containing more prey, independent of season, compared to simpler structured morphotypes such as Dictoytales. The study furthermore related juvenile fish density to habitats dominated by different algae morphotypes. Out of the three-study species (Diplodus vulgaris, Symphodus ocellatus, Coris julis) only S. ocellatus showed a significant association with an algae habitat. S. ocellatus related positively to habitats dominated by Dictoytales which provided the highest cover during late summer but had the lowest prey densities. A strong association of this species with Cystoseira, as reported by other studies, could not be confirmed. Cystoseira was abundant within the study area but in a state of dieback, showing loss and reduced height of foliage, typical for the time of year within the study area. It is therefore likely that algae-fish associations are context-dependent and that several algae species may fulfil similar functions. We also discovered that prey biomass did not appear to have an important effect on juvenile abundances. Nevertheless, the availability of prey may influence juvenile fish condition, growth performance and ultimately long-term survival. We therefore suggest that future studies on habitat quality should also include, besides abundance, indicators related to the condition and growth of juveniles.

Further studies on epidemiological factors influencing control of banana bunchy top disease and evaluation of control measures by computer simulation

1987 ◽  
Vol 38 (2) ◽  
pp. 373
Author(s):  
RN Allen
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Significant Loss ◽  
Control Measures ◽  
Disease Spread ◽  
Disease Symptoms ◽  
Control Disease ◽  
Banana Leaves ◽  
Time Required ◽  
Apparently Healthy

The basic infection rate of bunchy top disease in established bananas averaged 0.0342 new infections per infectious plant per day, but varied seasonally with a maximum in summer. The mean distance of spread for the aphid vector was 15.2 m. The latent period was 59.8 days and correlated with the time required for the growth of 3.7 new banana leaves. A microcomputer program was written to simulate spread of banana bunchy top disease in space and time. In the absence of disease control, disease spread from an initial primary infection in July or January to 124 or 153 infected plants, respectively, in one year. When disease control was maintained by removing diseased plants whenever the number of infected plants exceeded a given threshold, the numbers of diseased plants detected each inspection were positively correlated with the infection threshold, but the numbers of inspections required to maintain control increased markedly as the infection threshold was decreased. A practice of removing apparently healthy plants within 5 m of plants detected with bunchy top disease symptoms in five or more leaves was found to locate about 30% of the remaining undetected infected plants when disease was first detected in a plantation. However, its use as a routine control measure was ineffective in reducing the number of inspections required to maintain control or in reducing the risk of disease spreading to adjoining plantations. Removal of apparently healthy plants within 5 m had some bearing on disease control when applied around plants with disease symptoms in two leaves or less, but also caused a significant loss of healthy plants.

Factors influencing the development of bacterial blight of peas.

1954 ◽  
Vol 5 (3) ◽  
pp. 365 ◽  
Author(s):  
DC Wark
Keyword(s):  
Soil Moisture ◽  
Low Temperature ◽  
Moisture Content ◽  
Bacterial Blight ◽  
Soil Moisture Content ◽  
Atmospheric Humidity ◽  
Disease Symptoms ◽  
High Soil Moisture ◽  
Factors Influencing ◽  
Number Of Bacteria

Garden peas commonly carry a nucleus of plants with bacterial blight (Pseudomonas pisi Sackett) in a masked form. When such plants were exposed to low temperature, either by natural frosting or by dipping the tops of the plants in cold liquids, the number of bacteria in the tissues increased rapidly and typical symptoms of the disease occurred in a few days. Soil type and soil moisture content also influenced the development of the disease, which was more marked in peas grown on a red loam from the Dickson Experiment Station than in peas grown on a prepared potting soil. Disease symptoms developed more rapidly a t high soil moisture content than at lower soil moisture content, following exposure to high atmospheric humidity.

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