DOCSLIB.ORG

Tolerance of Different Host-Plants to the Cassava Mealybug Phenacoccus Manihoti Mati Le-Ferrero (Homoptera: Pseudococcidae)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Tolerance of Different Host-Plants to the Cassava Mealybug Phenacoccus Manihoti Mati Le-Ferrero (Homoptera: Pseudococcidae) Tolerance of different host-plants to the cassava mealybug Phenacoccus manihoti Mati le-Ferrero (Homoptera: Pseudococcidae) (Keywords: Phenacoccus manihoti, cassava, insect-plant relationship, antibiosis, tolerance, varietal resistance, Congo) B. LE RU and M. TERTULlANO Laboratoire d'Entomologie Agricole, ORSTOM, BP 181, Brazzaville, R. du Congo Abstract. The tolerance of seven varieties of cassava (Manihot Aphididae (Dixon, 1971 a,b; Barlow et al., 1977; Barlow esculenta Crantz), Poinsettia (Euphorbia ptncbetrime Wild.), and Messmer, 1982; Hawkins et al., 1985, 1986). Their Talinum (Talinum triangulare Jacq.) and Faux-caoutchouc (a quantification provides a useful tool to evaluate the degree hybrid of M. esculenta and M. glaziovii Mull. Arg.) to the cassava of plant tolerance (Jimenez et al., 1989; Scott et aI., 1991; mealybug Phenacoccus manihoti Matt. Ferr., was measured in the laboratory, by quantifying morphological and physiological Webster et al., 1991). changes in the growth of plants infested with P. menihotl. A 2­ When evaluating components of host-plant resistance month infestation by 100 mealybugs decreased the total leaf area to P. manihoti, different degrees of resistance in terms of and the leaf area ratio but did not modify total dry weight, F, antixenosis and antibiosis have been demonstrated (Le relative growth rate R or net assimilation rate E of plants studied. Ru et al., 1991 a). The aim of the present study is to The decrease in leaf area was extremely variable and depended on plant species and variety. The effect of infestation on dry determine the cassava tolerance to P. manihoti by quan­ weight of different plant organs was not homogeneous, suggest­ tifying morphological and physiological changes in their ing that translocation of nutrients made during photosynthesis growth caused by pest infestation. was modified. In cassava the decrease in leaf area, without significant change in leaf dry weight, appeared to be due to physiological changes in plants similar to those induced by water stress. The degree of tolerance was not related to the plant 2. Materials and methods species (cassava varieties Ganfo, Incoza and Zanaga were as tolerant as Talinum and Faux-caoutchouc). The 10 host-plants used in this study were selected according to the results obtained in a previous experi­ ment done to assess the antixenotic and antibiotic rela­ tionships between P. manihoti and its host-plants (Le RO 1. Introduction et al., 1991 a). The seven varieties of cassava (M. esculenta) have a varying degree of resistance in terms of antixenosis Tolerance is a component of plant resistance and re­ and antibiosis (high resistance: Incoza, Moudouma, and lates to its capacity to withstand insect attacks which Zanaga; medium resistance: M'Pembe, 30 M7; low resist­ would otherwise affect the growth of susceptible plants ance: 3 M8, Ganfo). (Horber, 1980). Unlike antixenosis and antibiosis, it does We also measured the tolerance of Faux-caoutchouc (a not exert a strong selective pressure on insect pest popu­ hybrid of M. esculenta and M. glaziovii Mull. Arg.), Tall­ lations; thus it can be maintained in a population over a num (Talinum triangulare Jaq., Portulacacae) and Poin­ long period (Auclair, 1989; Jimenez et al., 1988). settia (Euphorbia pulcherrima Wild., Euphorbiaceae); Cassava (Manihot esculenta Crantz; Euphorbiaceae) is their biological characteristics are as follows: a perennial shrub plant, relatively tolerant to diseases and pests because, unlike most other cultivated plants, it does 1. Faux-caoutchouc hosts large populations of P. not have critical phases during its development which can manihoti throughout the year, unlike cassava on possibly affect the yield. However, yield losses are high if which they are present for only 3-5 months the lifespan of leaves and the rate of photosynthesis are (Iheagwam, 1981). decreased or if stems are damaged severely (Cock, 1979). 2. Talinum is a weedy plant found in cassava fields, and A field experiment done in Nigeria has shown that the can sometimes host large populations of cassava infestation of cassava by the mealybug Phenacoccus mealybugs (Neuenschwander et et., 1986). manihoti Matile Ferrero (Homoptera; Pseudococcidae) 3. Poinsettia is sometimes used in the laboratory as results in a yield loss ranging between 52% and 58% in a substitute for cassava to mass-rear mealybugs 12-month-old plants. This loss might be due to a decrease (A. Panis and J. Boussienguet, personal communica­ in growth rate and leaf area; the latter might strongly tion), although it is never infested with this pest influence the total production of dry matter and its redis­ under natural conditions in Congo. tribution to roots (Schulthess et al., 1991). These modifications in growth due to the infestation of Plants were obtained from 30 cm cuttings planted vertically P. manihoti are similar to those induced by other sucking with two-thirds of their length in soil held in plastic pots insects such as Cicadellidae (Andrzejewska, 1967) and (30 x 22 cm). Pots were left in the shade for 2 weeks to 0967-0874/93 $10'00 © 1993 Taylor and Francis Lld stimulate the rooting process. Thereafter they were placed where W o and W 1 are the total dry weights at the begin­ in full light untit the 9-1 O-Ieaf stage (about 70 cm in height) ning (To) and end (Td of the time period; R indicates the which took 9-10 weeks. Pots (30 of each host-plant) were variation in plant weight per unit of time. then left for a further 2 months in a growth chamber under The rate of net assimilation Ë is: controlled conditions with an average temperature of 25°C (minima-maxima 21-32°C) and an average relative humidityof 70% (ranging between 60% and 80%); photo­ where A o and A 1 are the leaf areas at times To and T 1 period was 12 hours L:D. Under these experimental con­ respectively; Ë is an approximate measure of the net ditions we obtained after a 4-month period, plants with photosynthetic rate (Causton and Venus, 1981). In a con­ approximately 20 leaves and about 90-100 cm in height. stant environment, Ë can be considered as an index of the Under natural conditions in Congo, attacks by mealybugs plant's productive efficiency (Williams, 1946). occur at the beginning of the dry season on plants 3-8 The leaf area ratio Fis: months otd derived from the propagation of cassava cut­ tings, mostiy performed between November and April. Pots were watered twice a week during ail the experiment. This is a morphological index of the plant, and assumes The strain of P. manihoti (species reproducing by thely­ that leaves are the sole assimilatory organs (Causton and tocous parthenogenesis) used for the experiment in the Venus, 1981). laboratory was collected on the M'Pembe variety in the Mean values were analysed statistically using at-test at vegetable crop area of Brazzaville in October 1988. In the 5% level. order to Hmit the influence of parental trophic feeding mealybugs were reared for four generations (6 months) on 3. Results and Discussion each of the host-plants used in this experiment. At time 0 (To), 15 plants per host-plant, of identical size, Infestation of P. manihoti decreased the total leaf area of without symptoms of African cassava mosaic virus, were ail host-plants studied; however, this decrease was signi­ chosen amongst the 30 cuttings prepared initially. These ficant only for the Faux-Caoutchouc and for varieties of were divided randomly into two groups: one group of five cassava Moudouma, Ganfo Zanaga, 30 M7 and M'pembe. plants which was harvested 2 months later at time T1 • Infestation also reduced significantly the average number Each pair consisted of a control plant (non-infested) and a of leaves in the varieties of cassava 3 M8 and 30 M7, as weil treated plant (infested with 100 neonate mealybug L1 as the average number of internodes in the variety 3 M8 larvae, less than a day old). These conditions of infestation and Talinum, and the stem length between internodes in (100 mealybugs per plant for 2 months) were representa­ the variety Moudouma (Table 1). The general decrease in tive of the maximum number usually observed 2 months leaf area was found to depend on the plant itself. Com­ after the beginning of gradation in Congo (Le Rü et al., pared to Schulthess et al. 's (1991) work on only one variety 1991b). The artificial infestation is done on the second and of cassava (TMS 30572), our study shows that although third leaves from the apex with young neonate larvae. the infestation of P. manihoti is characterized by a de­ They attach themselves to the plant within the first 48 crease in leaf area, it can be variable depending on the hours, resulting in a homogeneous infestation of plants by variety, and ranges between 7% and 56%. When plant P. manihoti. We then count and readjust their number to growth was analysed in detail-for instance by taking into 100 (by removing or adding mealybugs of the same stage) account the average number of leaves, number and aver­ during ail experiments, in order to have an identical num­ age length of internodes-we then found that the develop­ ber on ail infested plants. Finally, when mealybugs reach ment of plants was affected only to a small extent by the L4 stage with ovisacs, we remove the ovisacs each mealybug infestation (Table 1). When infestation modified week to prevent new larvae from hatching and to keep the plant growth significantiy, it decreased either the lifespan total number constant. of leaves (30 M7) or their rate of development (Talinum) or The following parameters were determined at time To both (3 M8). Our results do not suggest a general pattern and T1 on control and experimental plants for each host­ for the effect of mealybug infestation on the growth of plant: the average number of leaves, the average number cassava.
Load more

Recommended publications
  • Effect of Invasive Pest Phenacoccus Manihoti Matile-Ferrero (Hemiptera; Pseudococcidae) in Cassava Nila Wardani1, Aunu Rauf2, I Wayan Winasa2, Sugeng Santoso2
    International Journal of Environment, Agriculture and Biotechnology (IJEAB) Vol-4, Issue-5, Sep-Oct- 2019 https://dx.doi.org/10.22161/ijeab.45.24 ISSN: 2456-1878 Effect of Invasive Pest Phenacoccus manihoti Matile-Ferrero (Hemiptera; Pseudococcidae) in Cassava Nila Wardani1, Aunu Rauf2, I Wayan Winasa2, Sugeng Santoso2 1Lampung Assesment Institute for Agriculture Technology, Jl. ZA. Pagar Alam No. IA, Bandar Lampung, email: [email protected] 2Department of Plant Protection, Bogor Agricultural University, Dramaga Campus, Bogor, West Java, Indonesia 16680 Abstract—Heavy damage by the cassava mealybug, Phenacoccua manihoti Matile-Ferrero (Hempiptera: Pseudococcidae) caused symptoms of bunchy top, shortened and distorted nodes, leaf drops, and inhibition of plant growth. The consequences of these pests can cause yield losses of 80%. This study was to determine the development of P. manihoti and cassava yield loss. Field observations indicated that symptoms of bunchy top appeared as early as 8 weeks after planting (wap) and rose quickly started 16 wap, at the same time with the advent of the dry season (May-June). Level of infestation developed faster on variety Jimbul; at 18 wap all plants had bunchy tops. While on varieties Roti and Manggu, 100% infestation occurred at 30 and 36 wap, respectively. There was a correlation between early infetation with plant height ang yield. Cassava plants infested during early stage were shorter and the yield lower, compared to those infested at further stages. Lower yields of variety Jimbul (0.94 kg/tree) than variety Manggu (3.16 kg/plant), was thought to be related to heavy infestation which occurred during early stage.
    [Show full text]
  • Factors Influencing the Life Table Statistics of the Cassava Mealybug Phenacoccus Manihoti
    Insect Sci. Applic. Vol. 8, Nos 4/5/6, pp. 851-856, 1987 0191-9040/87 $3.00 + 0.00 Printed in Great Britain. All rights reserved © 1987 ICIPE—ICIPE Science Press FACTORS INFLUENCING THE LIFE TABLE STATISTICS OF THE CASSAVA MEALYBUG PHENACOCCUS MANIHOTI F. SCHULTHESS1, J. U. BAUMGARTNER2 and H. R. HERREN1 'International Institute of Tropical Agriculture, Oyo Road, PMB 5320, Ibadan Nigeria; 'Institute of Phytomedicine, Swiss Federal Institute of Technology, 8092 Zurich, Switzerland (Received 27 November 1986) Abstract—Detailed age-specific life table studies were carried out under controlled conditions to measure the effect of temperature, leaf quality (= age), variety and plant drought stress on net production rate (RQ), intrinsic rate of increase (rm) and generation time (G) of Phenacoccus manihoti Mat.-Ferr. in order to explain changes in population densities observed in the field. The developmental threshold calculated from our data and results published by various authors was 14.7°C. At 35°C all mealybugs died before reaching the adult stage. Mealybugs reared on leaves of different ages showed little differences in rm, and the higher occurrence of P. manihoti on plant tips and oldest leaves could not be explained with better nutritive value of these plant parts alone. Cassava varieties have a strong influence on the intrinsic rate of increase, which could explain differences in results published by other authors. Plant drought stress had little influence on the life table statistics, but rainfall is assumed to be a determinant factor in the dynamics of the mealybug. Key Words: Age-specific life tables, temperature, leaf quality, variety, plant drought stress Resume—Des etudes visant a etablir une table de survie detaillee par categories d'age ont ete menees en environnement controle arm d'evaluer l'impact de la temperature, de la qualite du feuillage (age), de la variete et des contraintes hydriques sur le taux de production net (/?o)> ^e taux de croissance intrinseque (rm) et la duree des generations (G) de Phenacoccus manihoti Mat.-Ferr.
    [Show full text]
  • The Potential Distribution of Cassava Mealybug (Phenacoccus Manihoti), a Threat to Food Security for the Poor
    RESEARCH ARTICLE The potential distribution of cassava mealybug (Phenacoccus manihoti), a threat to food security for the poor Tania Yonow1,2, Darren J. Kriticos1,2,3*, Noboru Ota4 1 HarvestChoice, InSTePP, University of Minnesota, St. Paul, MN, United States of America, 2 CSIRO, Canberra ACT, Australia, 3 The University of Queensland, School of Biological Sciences, St. Lucia, QLD, Australia, 4 CSIRO, Wembley WA, Australia a1111111111 * [email protected] a1111111111 a1111111111 a1111111111 a1111111111 Abstract The cassava mealybug is a clear and present threat to the food security and livelihoods of some of the world's most impoverished citizens. Niche models, such as CLIMEX, are useful tools to indicate where and when such threats may extend, and can assist with planning for OPEN ACCESS biosecurity and the management of pest invasions. They can also contribute to bioeconomic Citation: Yonow T, Kriticos DJ, Ota N (2017) The analyses that underpin the allocation of resources to alleviate poverty. Because species can potential distribution of cassava mealybug invade and establish in areas with climates that are different from those that are found in (Phenacoccus manihoti), a threat to food security their native range, it is essential to define robust range-limiting mechanisms in niche models. for the poor. PLoS ONE 12(3): e0173265. doi:10.1371/journal.pone.0173265 To avoid spurious results when applied to novel climates, it is necessary to employ cross- validation techniques spanning different knowledge domains (e.g., distribution data, experi- Editor: Nikos T. Papadopoulos, University of Thessaly School of Agricultural Sciences, GREECE mental results, phenological observations). We build upon and update a CLIMEX niche model by Parsa et al.
    [Show full text]
  • Cassava-Mealybug Interactions
    Cassava-Mealybug Interactions Paul-André Calatayud Bruno Le Rü IRD I ACTIQUES Diffusion ✓ support papier support cédérom Cassava–Mealybug Interactions La collection « Didactiques » propose des ouvrages pratiques ou pédagogiques. Ouverte à toutes les thématiques, sans frontières disciplinaires, elle offre à un public élargi des outils éducatifs ou des mises au point méthodologiques qui favorisent l’application des résultats de la recherche menée dans les pays du Sud. Elle s’adresse aux chercheurs, enseignants et étudiants mais aussi aux praticiens, décideurs et acteurs du développement. JEAN-PHILIPPE CHIPPAUX Directeur de la collection [email protected] Parus dans la collection Venins de serpent et envenimations Jean-Philippe Chippaux Les procaryotes. Taxonomie et description des genres (cédérom) Jean-Louis Garcia, Pierre Roger Photothèque d’entomologie médicale (cédérom) Jean-Pierre Hervy, Philippe Boussès, Jacques Brunhes Lutte contre la maladie du sommeil et soins de santé primaire Claude Laveissière, André Garcia, Bocar Sané Outils d’enquête alimentaire par entretien Élaboration au Sénégal Marie-Claude Dop et al. Awna Parikwaki Introduction à la langue palikur de Guyane et de l’Amapá Michel Launey Grammaire du nengee Introduction aux langues aluku, ndyuka et pamaka Laurence Goury, Bettina Migge Pratique des essais cliniques en Afrique Jean-Philippe Chippaux Manuel de lutte contre la maladie du sommeil Claude Laveissière, Laurent Penchenier Cassava–Mealybug Interactions Paul-André Calatayud Bruno Le Rü IRD Éditions INSTITUT DE RECHERCHE POUR LE DÉVELOPPEMENT Collection Paris, 2006 Production progress chasing Corinne Lavagne Layout Bill Production Inside artwork Pierre Lopez Cover artwork Michelle Saint-Léger Cover photograph: C. Nardon/Cassava mealybug (Phenacoccus manihoti) La loi du 1er juillet 1992 (code de la propriété intellectuelle, première partie) n’autorisant, aux termes des alinéas 2 et 3 de l’article L.
    [Show full text]
  • PEST ALERT Occurrence of Cassava Mealybug Phenacoccus Manihoti
    PEST ALERT Occurrence of cassava mealybug Phenacoccus manihoti Matile-Ferrero in India Phenacoccus manihoti Matile-Ferrero is one of the most destructive pests of cassava in the world. It is native to South America, but has become acclimatized throughout sub-Saharan Africa since its unintentional introduction into the continent in the early 1970s causing up to 84% loss of yield and endangering the subsistence of about 200 million people. This pest was not known to occur in Asia until 2008, when it was first detected in Thailand. At present the pest is distributed in Neotropical Region (Argentina, Bolivia, Brazil, Colombia, Paraguay); Australasian Region (Indonesia); African Region (Angola, Benin, Burundi, Congo, Côte d'Ivoire, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Malawi, Mali, Mozambique, Nigeria, Rwanda, Senegal, Sierra Leone, Sudan, Tanzania, Togo, Uganda, Zaire, Zambia, Zanzibar); and Oriental Region (Cambodia, Malaysia, Thailand and Vietnam). Cassava mealybug is known to infest plants belonging to 9 families viz., Cyperaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Malvaceae, Nyctaginaceae, Portulacaceae, Rutaceae and Solanaceae. Besides cassava, P. manihoti can infest crops like citrus, Solanum species and basil. So far thirty-three natural enemies have been recorded on this pest in other countries. In India, infestation of this pest was observed on around 2000 square meter experimental plot of cassava (Manihot esculenta Crantz) in Thrissur, Kerala (Fig. 1 A). All the stages of mealybug viz., eggs, nymphs and adults (Fig. 1 B & C) were observed on all the plant parts including undersurface of leaves (Fig. 1 D) causing curling up of the leaves at growing tip of the plant leading to formation of bunchy tops (Fig.
    [Show full text]
  • Impact Assessment of the Biological Control of the Cassava
    CORE Metadata, citation and similar papers at core.ac.uk Provided by RERO DOC Digital Library Bull. ent. Res. 79, 579-594 579 Published 1989 Impact assessment of the biological control of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), by the introduced parasitoid Epidinocarsis lopezi (De Santis) (Hymenoptera: Encyrtidae) P. NEUENSCHWANDER and W. N. O. HAMMOND Biological Control Programme, International Institute of Tropical Agriculture, Benin Research Station, B.P. 062523 Cotonou, Benin A. P. GUTIERREZ Division of Biological Control, University of California, Berkeley, 1050 San Pablo Avenue, Albany, CA 94706, USA A. R. CUDJOE and R. ADJAKLOE Plant Protection and Quarantine Unit, Department of Agriculture, P.O. Box M37, Accra, Ghana J. U. BAUMGARTNER Division of Phytomedicine, Swiss Federal Institute of Technology, ETH-Zentrum, Zurich, Switzerland U. REGEV Department of Economics, Ben Gurion University, Beersheva, Israel Abstract The impact of Phenacoccus manihoti Matile-Ferrero on growth and tuber yield of cassava, and the results of its biological control by the exotic parasitoid Epidinocarsis lopezi (De Santis) were investigated in a survey of 60 farmers' fields in Ghana and Ivory Coast over an area of 180 000 km2 of the savanna and forest ecosystems. Twenty-nine variables associated with plant growth, agronomic and environmental factors, and insect populations were recorded. Densities of P. manihoti were closely correlated with stunting of the cassava shoot tips and, less so, with the rate of stunting early in the growing season. With increasing mealybug infestations, average harvest indi- ces declined and populations of E. lopezi and of indigenous coccinellids increased, but parasitoids were found at lower host levels than were preda- tors.
    [Show full text]
  • Biology of Prochiloneurus Insolitus (Alam) (Hymenoptera, Encyrtidae)
    Biology of Prochiloneurus insolitus (Alam) (Hymenoptera, Encyrtidae), a hyperparasitoid on mealybugs (Homoptera, Pseudococcidae) : immature morphology, host acceptance and host range in West Africa Autor(en): Goergen, G. / Neuenschwander, P. Objekttyp: Article Zeitschrift: Mitteilungen der Schweizerischen Entomologischen Gesellschaft = Bulletin de la Société Entomologique Suisse = Journal of the Swiss Entomological Society Band (Jahr): 63 (1990) Heft 3-4: Gedenkschrift zum Rücktritt von Prof. Dr. Vittorio Delucchi PDF erstellt am: 30.09.2021 Persistenter Link: http://doi.org/10.5169/seals-402404 Nutzungsbedingungen Die ETH-Bibliothek ist Anbieterin der digitalisierten Zeitschriften. Sie besitzt keine Urheberrechte an den Inhalten der Zeitschriften. Die Rechte liegen in der Regel bei den Herausgebern. Die auf der Plattform e-periodica veröffentlichten Dokumente stehen für nicht-kommerzielle Zwecke in Lehre und Forschung sowie für die private Nutzung frei zur Verfügung. Einzelne Dateien oder Ausdrucke aus diesem Angebot können zusammen mit diesen Nutzungsbedingungen und den korrekten Herkunftsbezeichnungen weitergegeben werden. Das Veröffentlichen von Bildern in Print- und Online-Publikationen ist nur mit vorheriger Genehmigung der Rechteinhaber erlaubt. Die systematische Speicherung von Teilen des elektronischen Angebots auf anderen Servern bedarf ebenfalls des schriftlichen Einverständnisses der Rechteinhaber. Haftungsausschluss Alle Angaben erfolgen ohne Gewähr für Vollständigkeit oder Richtigkeit. Es wird keine Haftung übernommen für
    [Show full text]
  • First Record of Cassava Mealybug, Phenacoccus Manihoti (Hemiptera: Pseudococcidae), in Malaysia
    Zootaxa 3957 (2): 235–238 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Correspondence ZOOTAXA Copyright © 2015 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.3957.2.8 http://zoobank.org/urn:lsid:zoobank.org:pub:5C879096-2FE8-4873-8C34-A3380D545E9A First record of cassava mealybug, Phenacoccus manihoti (Hemiptera: Pseudococcidae), in Malaysia DEWI SARTIAMI1, GILLIAN W. WATSON2, MOHAMAD ROFF M.N3., MOHD HANIFAH Y3 & IDRIS. A.B1 1School of Environmental and Natural Sciences, Faculty of Science and Technology, National University of Malaysia, Bangi 43000, Selangor, Malaysia. E-mail addresses: [email protected] and [email protected] 2Plant Pest Diagnostic Center, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento CA 95832, Sacramento, California, U.S.A. E-mail: [email protected] 3Horticulture Research Center, Malaysian Agricultural Research and Development Institute, Persiaran MARDI-UPM, 43400 Serdang, Selangor, Malaysia. E-mail addresses: [email protected] and [email protected] Cassava (Manihot esculenta Crantz, Euphorbiaceae) is an important staple food crop in tropical countries. The leaves and tubers are used for human consumption and livestock feed. The tubers are processed into starch (Winotai et al. 2010) and biofuel (Howeler 2007). In Africa, cassava is a particularly important crop because the tubers can be stored to provide staple food during severe droughts (Calatayud & Le Rü 2006). In the 1970s, an undescribed mealybug (Hemiptera: Pseudococcidae) of Neotropical origin was accidentally introduced into West Africa and devastated the cassava crop, causing up to 84% loss of yield (Nwanze 1982) and endangering the subsistence of about 200 million people (Herren & Neuenschwander 1991).
    [Show full text]
  • Special Paper Series 28
    The Biotechnology Revolution and its Implication for Food Security in Africa Victor Konde ATPS SPECIAL PAPER SERIES No. 28 Published by the African Technology Policy Studies Network, P.O. Box 10081, 00100 General Post Office, Nairobi, Kenya. © 2006 African Technology Policy Studies Network (ATPS) PUBLISHED BY ATPS COMMUNICATIONS DEPARTMENT Printed by Newtec Concepts P.O. Box 00800, Westlands 14180 Nairobi, Kenya Tel: 4449849, Fax: 4450399 [email protected] ISBN: 9966-916-95-4 ABOUT THE AFRICAN TECHNOLOGY POLICY STUDIES NETWORK The African Technology Policy Studies Network (ATPS) is a multi-disciplinary network of researchers, policy makers, actors in the private sector and other end users interested in generating, promoting and strengthening innovative science and technology policies in Africa. With a regional secretariat in Nairobi, the network operates through national chapters in 23 countries, with an expansion plan to cover the entire sub-Saharan Africa. One of the objectives of the network is to disseminate research results to policy makers, legislators, the organized private sector, civil society, mass media and farmers’ groups through publications, dialogue and advocacy. Among its range of publications are the Working Paper Series (WPS), Research Paper Series (RPS), Special Paper Series (SPS) and the Technopolicy Briefs. Papers published under the ATPS Special Paper Series are those commissioned as concept papers, think pieces, leading conference papers and keynote addresses. In keeping with our knowledge brokerage function, ATPS publishes, with permission of the author(s) or journal editors, papers (published or unpublished) produced by distinguished academics/ researchers for a different purpose but judged by ATPS to be of excellent quality.
    [Show full text]
  • Economics of Biological Control of Cassava Mealybug in Africa
    AGRICULTURAL ECONOMICS ELSEVIER Agricultural Economics 24 (200 1) 209-219 www.elsevier.com/locate/agecon Economics of biological control of cassava mealybug in Africa J. Zeddiesa, R.P. Schaaba, P. Neuenschwanderb·*, H.R. Herrenb,l a University of Hohenheim, Institute ofAgricultural Economics (410 B), D-70593 Stuttgart, Germany b International Institute of Tropical Agriculture (l/TA), 08 B.P. 0932, Cotonou, Benin Received 24 December 1997; received in revised form 16 February 2000; accepted 9 March 2000 Abstract Pest populations of the cassava mealybug Phenacoccus manihoti Mat.-Ferr. (Homoptera: Pseudococcidae) were reduced successfully by the biological control agent Apoanagyrus (Epidinocarsis) lopezi De Santis (Hymenoptera: Encyrtidae) throughout most of sub-Saharan Africa. The economics of the project were evaluated based on data from field trials, socio-economic surveys, published results, and financial information provided by the International Institute of Tropical Agriculture (IITA) and the national programmes. Costs and benefits for the biological control of P. manihoti were calculated over 40 years (1974-2013) for 27 African countries, for four different scenarios, taking into account that impact by A. lopezi and speed of the impact differ between ecological zones. A reasonable calculation considering compounded interest resulted in a benefit cost ratio of about 200 when cassava was costed at world market prices, and of about 370-740 when inter-African prices were considered.© 2001 Elsevier Science B.V. All rights reserved. Keywords: Economics of biological control; Phenacoccus manihoti; Apoanagyrus lopezi; Cassava; Africa 1. Introduction decade, the biological control agent had spread to all the major mealybug infestations and had brought the The cassava mealybug Phenacoccus manihoti pest under control in 95% of all the fields (Herren Mat.-Ferr.
    [Show full text]
  • Biological Characteristics of the Cassava Mealybug Phenacoccus Manihoti (Hemiptera: Pseudococcidae)
    Revista Colombiana de Entomología 40 (1): 21-24 (2014) 21 Biological characteristics of the cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) Características biológicas del piojo harinoso de la yuca, Phenacoccus manihoti (Hemiptera: Pseudococcidae) DIANDRO R. BARILLI1, VANDA PIETROWSKI2, ANA P. G. DA S. WENGRAT3, DIEGO GAZOLA4 and RUDINEY RINGENBERG5 Abstract: The cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) feeds by sucking the sap of cassava plants, causing damage directly by sucking the sap and contaminating the plant with its toxic saliva and indirectly by favoring the development of sooty molds. To establish an integrated pest management program, information about the biology of pest species is basic. Thus, the objective of this study was to determine some biological characteristics of Ph. manihoti on cassava. The experiment was conducted using Santa Helena cultivar which was kept in a semi-heated room at an average temperature of 25 °C. Approximately 20 newly oviposited eggs were placed on four apical leaves of each plant. After the eggs had hatched, only one first-instar nymph was left per leaf. The mealybug nymphs were examined on a daily basis; information on molting time was recorded and data on mortality and oviposition were used to construct a fertility life table. The experiment was conducted with 90 replicates. The average duration of the egg, first-instar, second-instar, third-instar nymph and the adult stages were 7.7, 6.9, 4.9, 5.7 and 20.7 days, respectively. On average, the total life cycle lasted 45.22 days, and each female was able to produce a total of 247 eggs.
    [Show full text]
  • Nitrogen Fertilization in the Contents of Secondary Compounds in Cassava Cultivars Semina: Ciências Agrárias, Vol
    Semina: Ciências Agrárias ISSN: 1676-546X ISSN: 1679-0359 Universidade Estadual de Londrina Gazola, Diego; Zucareli, Claudemir; Ringenberg, Rudiney; Graça, José Perez da; Hoffmann-Campo, Clara Beatriz Nitrogen fertilization in the contents of secondary compounds in cassava cultivars Semina: Ciências Agrárias, vol. 39, no. 3, 2018, May-June, pp. 1015-1027 Universidade Estadual de Londrina DOI: https://doi.org/10.5433/1679-0359.2018v39n3p1015 Available in: https://www.redalyc.org/articulo.oa?id=445760189009 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Journal's webpage in redalyc.org Portugal Project academic non-profit, developed under the open access initiative DOI: 10.5433/1679-0359.2018v39n3p1015 Nitrogen fertilization in the contents of secondary compounds in cassava cultivars Adubação nitrogenada nos teores de compostos secundários em cultivares de mandioca industrial Diego Gazola1*; Claudemir Zucareli2; Rudiney Ringenberg3; José Perez da Graça4; Clara Beatriz Hoffmann-Campo3 Abstract The production of chemical substances is a strategy of plants to defend against the attack of pest insects. The synthesis of secondary compounds in plants is influenced by genotype and cultural management, such as the use of nitrogen fertilizers. Thus, the objective of this work is to evaluate the effect of doses of nitrogen fertilizer over time on the production of secondary compounds in two industrial cassava cultivars. The experiment was carried out in a greenhouse (25 ± 5 °C) of Embrapa Soybean in Londrina, Paraná, with the cultivation of potted plants (4l) in a 2 × 4 × 3 factorial scheme, with five replications.
    [Show full text]