Relationship of Cassava Mosaic Severity in Planting Material to Mosaic Development, Growth and Yield of Cassava in Zaire

1987 ◽  
Vol 23 (2) ◽  
pp. 221-225 ◽  
Author(s):  
A. Muimba-Kankolongo ◽  
K. Phuti

SummaryThe performance of a cassava clone susceptible to cassava mosaic disease (CMD) was tested over two successive years for CMD development, plant vigour and yield of fresh tuberous roots. Cuttings from plants with different CMD infection levels were used. There was a significant increase in mosaic incidence, severity and proportion of leaves showing symptoms of the disease in the subsequent crop as the levels of CMD primary infection in planting material increased. Plant height and stem diameter were also adversely affected and the yield of plants from severely affected cuttings was reduced by 60–70%.

2017 ◽  
Vol 13 (2) ◽  
pp. 94-102
Author(s):  
Dessy A Ralahalu ◽  
Rhony E Ririhena ◽  
Abdul K Kilkoda

This study aims to examine the effect of concentration of liquid organic fertilizer supermes on various spacing to the growth and yield of onion. The experiment was conducted in Dusun Telaga Kodok, Hitu Lama Village, Leihitu Barat District, Central Maluku District, from March to April 2017. The experiment used was a Randomized Block Design with three replications. The concentration of liquid organic fertilizer supermes consists of: 0, 2, 4, 6 mL/L water. Plant ing distance consists of: 10 × 15 cm, 15 × 15 cm and 20 × 15 cm. Varieties used were varieties of Bima Brebes. Parameters measured were plant height, number of leaves, number of tubers, root length, wet weight and dry weight of tubers. During the experiment, rainfall and rainy days were quite high at the research location. This condition causes the crop to be harvested at 41 HST because it is attacked by ground caterpillar, mosaic disease and purple spots. The application of liquid organic fertilizer has not shown any significant effect to the growth and yield parameters of shallot crop. Planting distance of 15 × 15 cm shows the effect on plant height and number of leaves at 35 HST, tuber weight and tuber dry weight and there is a significant interaction on the leaf number at 35 HST with concentration of 4 mL/L water and Planting Distance 15 × 15 cm. Keywords: liquid organic fertilizer, planting distance, red onion   ABSTRAK Penelitian ini bertujuan untuk menguji pengaruh konsentrasi pupuk organik cair supermes pada berbagai jarak tanam terhadap pertumbuhan dan hasil bawang merah. Penelitian dilaksanakan di Dusun Telaga Kodok, Desa Hitu Lama Kecamatan Leihitu Barat, Kabupaten Maluku Tengah, dari bulan Maret sampai dengan April 2017. Percobaan menggunakan Rancangan Acak Kelompok dengan tiga ulangan. Konsentrasi pupuk organik cair Supermes terdiri dari 0, 2, 4, 6 mL/L air. Jarak tanam terdiri dari 10 ×15 cm, 15 × 15 cm, dan 20 × 15 cm. Varietas yang digunakan adalah varietas Bima Brebes. Paramater yang diukur adalah tinggi tanaman, jumlah daun, jumlah umbi, panjang akar, bobot basah dan bobot kering umbi. Selama percobaan berlangsung curah hujan dan hari hujan cukup tinggi terjadi di lokasi penelitian. Kondisi ini menyebabkan tanaman dipanen pada umur 41 HST karena diserang oleh hama ulat tanah, penyakit mozaik dan bercak ungu. Pemberian pupuk organik cair belum memberikan pengaruh yang nyata terhadap parameter pertumbuhan dan hasil tanaman bawang merah. Jarak tanaman 15 × 15 cm berpengaruh terhadap tinggi tanaman dan jumlah daun pada 35 HST, bobot basah umbi dan bobot kering umbi serta adanya interaksi perlakuan yang nyata terhadap jumlah daun pada umur 35 HST dengan konsentrasi 4 mL/L air dan jarak tanam 15 × 15 cm. Kata kunci: bawang merah, jarak tanam, pupuk organik cair


2021 ◽  
Author(s):  
Anna Maria Szyniszewska ◽  
Patrick Chiza Chikoti ◽  
Mathias Tembo ◽  
Rabson Mulenga ◽  
Christopher Gilligan ◽  
...  

Cassava is an important food crop across sub-Saharan Africa, where production is severely inhibited by two viral diseases; cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), both propagated by a whitefly vector and via human-mediated movement of infected cassava stems. There is limited information on growers’ behaviour related to movement of planting material, as well as growers’ perception and awareness of cassava diseases, despite the importance of these factors for disease control. This study surveyed a total of 96 cassava subsistence growers and their fields across five provinces in Zambia between 2015 and 2017, to address these knowledge gaps. CMD symptoms were observed in 81.6% of the fields, with an average incidence of 52% across the infected fields. No CBSD symptoms were observed. Most growers used planting materials from their own (94%) or nearby (<10 km) fields of family and friends, although several large transactions over longer distances (10-350 km) occurred with friends (15 transactions), markets (1), middlemen (5), and NGOs (6). Information related to cassava diseases and certified clean (disease-free) seed reached only 48% of growers. The most frequent sources of information related to cassava diseases included nearby friends, family and neighbours, whilst extension workers were the most highly preferred source of information. These data provide a benchmark on which to plan management approaches to controlling CMD and CBSD, which should include clean propagation material, increasing growers' awareness of the diseases and increasing information provided to farmers (specifically disease symptom recognition and disease management options).


2019 ◽  
Author(s):  
Anna Maria Szyniszewska ◽  
Patrick Chiza Chikoti ◽  
Mathias Tembo ◽  
Rabson Mulenga ◽  
Frank van den Bosch ◽  
...  

AbstractCassava is an important food crop for most small-holder growers across sub-Saharan Africa, where production is largely limited by the presence of two viral diseases: cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), both propagated by a vector whitefly and via human-mediated movement of infected cassava stems. Despite its importance, there is limited knowledge of growers’ behaviour related to planting material movement, as well as growers’ perception and knowledge of cassava diseases, which have major implications for disease spread and control. This study was conducted to address this knowledge gap by surveying small-holder growers in Zambia. A total of 96 subsistence cassava growers across five provinces were surveyed between 2015 and 2017. Most growers interviewed used planting materials from their own fields (94%) or those of nearby (<10 km) family and friends, although some large transactions with markets, middlemen, and NGOs occurred over longer distances. At the same time, information related to cassava diseases and uninfected planting material only reached 48% of growers, where those with access to information were more concerned about the disease. These data provide a basis for future planning of cassava clean seed systems to control virus diseases, emphasising the critical role of grower knowledge, and consequently education, in success of these systems. In particular, we highlight the importance of extension workers in this education process, as well as farmer’s groups and the media.


2018 ◽  
Vol 9 (2) ◽  
pp. 153-163
Author(s):  
Wiwik Ambarsari ◽  
Henly Yuliana

The study aimed to determine the effect of the combination of city waste compost and cattle manure on the growth and yield of pakcoy plants (Brassica rapa, L. Chinensis) in Aluvial, Indramayu Regency. The study was conducted at the Experimental Garden of the Faculty of Agriculture, Wiralodra University, Indramayu Regency from March to August 2018. This study used Factorial Pattern Randomized Block Design with two factors. The first factor is city waste compost and the second factor is cattle manure with 4 levels: 0%, 3.0%, 6.0%, and 9.0%, repeated twice. The results showed that there was an independent influence between city waste compost and cattle manure on plant height and number of leaves. The best combination to increase the feasibility weight of pakcoy consumption is by giving city waste compost 9.0% (S4) and cattle manure 6.0% (K3).


2020 ◽  
pp. 1-12
Author(s):  
E. K. Al-Fahdawe ◽  
A. A. Al-Sumaidaie ◽  
Y. K. Al-Hadithy

A pots experiment was conducted at the Department of Biology/College of Education for Girls/University of Anbar during Autumn season of 2018-2019 to study the effect of the salinity irrigation water and spray by humic acid in some of morphological, physiological, growth and yield traits of wheat cv. IPa. The experiment was randomized complete block design (RCBD) with three replications. The first factor was assigned for irrigation by saline water at four level (S0, S1, S2 and S3), while the second factor was the foliar spraying of humic acid in three level (0.0, 1.0 and 1.5 g l-1). The results showed that there was significant reduction in plant height, vegetative dry weight, biological yield and chlorophyll leaves content when the plants were irrigated by saline water approached to 41.09 cm, 0.747 g, 0.849 g plant-1 and 38.67 SPAD, respectively at salinity level of 8.3 ds m-1 compared with the plants which irrigated by fresh water. The total carbohydrates were significantly decreased at the treatment of 8.3 ds m-1 reached 18.71 mg g-1. Spray levels humic acid achieved a significant increase in plant height, dry weight of the vegetative part, biological yield and chlorophyll leaves content sprayed at 1.0 and 1.5 g l-1 compared to no sprayed. Nitrogen concentration was significantly increased, while both phosphorus and potassium were decreased in the vegetative parts of wheat as the salinity of irrigation water increased. However, the increase of humic acid levels led to significant increasing in nitrogen, phosphorus and potassium concentration.


2021 ◽  
Vol 83 (8) ◽  
Author(s):  
F. Al Basir ◽  
Y. N. Kyrychko ◽  
K. B. Blyuss ◽  
S. Ray

AbstractMany plant diseases are caused by plant viruses that are often transmitted to plants by vectors. For instance, the cassava mosaic disease, which is spread by whiteflies, has a significant negative effect on plant growth and development. Since only mature whiteflies can contribute to the spread of the cassava mosaic virus, and the maturation time is non-negligible compared to whitefly lifetime, it is important to consider the effects this maturation time can have on the dynamics. In this paper, we propose a mathematical model for dynamics of cassava mosaic disease that includes immature and mature vectors and explicitly includes a time delay representing vector maturation time. A special feature of our plant epidemic model is that vector recruitment is negatively related to the delayed ratio between vector density and plant density. We identify conditions of biological feasibility and stability of different steady states in terms of system parameters and the time delay. Numerical stability analyses and simulations are performed to explore the role of various parameters, and to illustrate the behaviour of the model in different dynamical regimes. We show that the maturation delay may stabilise epidemiological dynamics that would otherwise be cyclic.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Saengsoon Charoenvilaisiri ◽  
Channarong Seepiban ◽  
Mallika Kumpoosiri ◽  
Sombat Rukpratanporn ◽  
Nuchnard Warin ◽  
...  

Abstract Background Cassava mosaic disease (CMD) is one of the most devastating viral diseases for cassava production in Africa and Asia. Accurate yet affordable diagnostics are one of the fundamental tools supporting successful CMD management, especially in developing countries. This study aimed to develop an antibody-based immunoassay for the detection of Sri Lankan cassava mosaic virus (SLCMV), the only cassava mosaic begomovirus currently causing CMD outbreaks in Southeast Asia (SEA). Methods Monoclonal antibodies (MAbs) against the recombinant coat protein of SLCMV were generated using hybridoma technology. MAbs were characterized and used to develop a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) for SLCMV detection in cassava leaves and stems. Assay specificity, sensitivity and efficiency for SLCMV detection was investigated and compared to those of a commercial ELISA test kit and PCR, the gold standard. Results A TAS-ELISA for SLCMV detection was successfully developed using the newly established MAb 29B3 and an in-house polyclonal antibody (PAb) against begomoviruses, PAb PK. The assay was able to detect SLCMV in leaves, green bark from cassava stem tips, and young leaf sprouts from stem cuttings of SLCMV-infected cassava plants without cross-reactivity to those derived from healthy cassava controls. Sensitivity comparison using serial dilutions of SLCMV-infected cassava sap extracts revealed that the assay was 256-fold more sensitive than a commercial TAS-ELISA kit and 64-fold less sensitive than PCR using previously published SLCMV-specific primers. In terms of DNA content, our assay demonstrated a limit of detection of 2.21 to 4.08 × 106 virus copies as determined by quantitative real-time PCR (qPCR). When applied to field samples (n = 490), the TAS-ELISA showed high accuracy (99.6%), specificity (100%), and sensitivity (98.2%) relative to the results obtained by the reference PCR. SLCMV infecting chaya (Cnidoscolus aconitifolius) and coral plant (Jatropha multifida) was also reported for the first time in SEA. Conclusions Our findings suggest that the TAS-ELISA for SLCMV detection developed in this study can serve as an attractive tool for efficient, inexpensive and high-throughput detection of SLCMV and can be applied to CMD screening of cassava stem cuttings, large-scale surveillance, and screening for resistance.


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