Cacao Trees (cacao + tree)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Activity of Bacillus thuringiensis toxins against cocoa pod borer larvae

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2004
Djoko Santoso
Abstract Twelve Cry proteins from Bacillus thuringiensis Berliner were tested in bioassays on cacao plantations in Indonesia for activity against the larvae of cocoa pod borer (Conopomorpha cramerella (Snellen)), an insect pest of the cacao tree. Through the damage caused by their feeding, the larvae of cocoa pod borer cause the pods of the cocoa tree to ripen prematurely. They are difficult to control with conventional measures. Preliminary assays identified five toxins that were more active than others. In two subsequent bioassays the activity of selected toxins was determined more accurately. Three Cry1 proteins with relatively little homology were all found to be toxic, opening perspectives for controlling cocoa pod borer by expression of Cry proteins in transgenic plants. Copyright © 2004 Society of Chemical Industry [source]

Water use characteristics of cacao and Gliricidia trees in an agroforest in Central Sulawesi, Indonesia

ECOHYDROLOGY, Issue 4 2009
Michael Köhler
Abstract Water use characteristics of cacao (Theobroma cacao) and Gliricidia sepium shade trees were studied in an agroforest on Sulawesi, Indonesia. The objectives were: (1) to identify environmental and tree structural factors controlling water use, (2) to analyse the effect of shade tree cover on cacao water use and (3) to estimate stand level transpiration. Sap flux density was measured in up to 18 trees per species and described with a Jarvis-type model. Model parameters suggested a 49% higher maximum sap flux density in cacao than in Gliricidia and species differences in the response to vapour pressure deficit and radiation. Tree water use was positively related to tree diameter in both species, but this relationship tended to differ between species. In cacao trees maximal tree water use increased with decreasing canopy gap fraction above the trees (R2adj = 0·39, p = 0·04). This was paralleled by an increase of cacao stem diameter and leaf area with decreasing gap fraction. Maximum water use rate per unit crown area of cacao was 13% higher than that of Gliricidia. At the stand level the average transpiration rate was estimated at 1·5 mm day,1 per unit ground area, 70% of which was contributed to by cacao. We conclude that, in the given stand, species differed substantially in water use characteristics, while estimated stand transpiration is in line with findings from other studies for cacao stands. Shade trees may enhance stand transpiration through own water use and additionally by increasing water use rates of cacao trees. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Moniliophthora perniciosa, the causal agent of witches' broom disease of cacao: what's new from this old foe?

MOLECULAR PLANT PATHOLOGY, Issue 5 2008
LYNDEL W. MEINHARDT
SUMMARY Moniliophthora perniciosa (=Crinipellis perniciosa) causes one of the three main fungal diseases of Theobroma cacao (cacao), the source of chocolate. This pathogen causes Witches' broom disease (WBD) and has brought about severe economic losses in all of the cacao-growing regions to which it has spread with yield reductions that range from 50 to 90%. Cacao production in South America reflects the severity of this pathogen, as the yields in most of the infected regions have not returned to pre-outbreak levels, even with the introduction of resistant varieties. In this review we give a brief historical account and summarize the current state of knowledge focusing on developments in the areas of systematics, fungal physiology, biochemistry, genomics and gene expression in an attempt to highlight this disease. Moniliophthora perniciosa is a hemibiotrophic fungus with two distinct growth phases. The ability to culture a biotrophic-like phase in vitro along with new findings derived from the nearly complete genome and expression studies clearly show that these different fungal growth phases function under distinct metabolic parameters. These new findings have greatly improved our understanding of this fungal/host interaction and we may be at the crossroads of understanding how hemibiotrophic fungal plant pathogens cause disease in other crops. Historical summary of WBD:, The first WDB symptoms appear to have been described in the diaries of Alexandre Rodrigues Ferreira (described as lagartão; meaning big lizard) from his observations of cacao trees in 1785 and 1787 in Amazonia, which is consistent with the generally accepted idea that M. perniciosa, like its main host T. cacao, evolved in this region. The disease subsequently arrived in Surinam in 1895. WBD moved rapidly, spreading to Guyana in 1906, Ecuador in 1918, Trinidad in 1928, Colombia in 1929 and Grenada in 1948. In each case, cacao production was catastrophically affected with yield reductions of 50,90%. After the arrival of M. perniciosa in Bahia in 1989, Brazil went from being the world's 3rd largest producer of cacao (347 000 tonnes in 1988,1990; c. 15% of the total world production at that time) to a net importer (141 000 tonnes in 1998,2000). Fortunately for chocolate lovers, other regions of the world such as West Africa and South East Asia have not yet been affected by this disease and have expanded production to meet growing world demand (predicted to reach 3 700 000 tonnes by 2010). Classification:,Moniliophthora perniciosa (Stahel) Aime & Phillips-Mora: super-kingdom Eukaryota; kingdom Fungi; phylum Basidiomycota; subphylum Agaricomycotina; class Agaricomycetes; subclass Agaricomycetidae; order Agaricales; family Marasmiaceae; genus Moniliophthora. Useful websites:,http://www.lge.ibi.unicamp.br/vassoura/, http://nt.ars-grin.gov/taxadescriptions/keys/TrichodermaIndex.cfm, http://www.worldcocoafoundation.org/info-center/research-updates.asp, http://www.ars.usda.gov/ba/psi/spcl [source]

Phenological growth stages of cacao plants (Theobroma sp.): codification and description according to the BBCH scale

ANNALS OF APPLIED BIOLOGY, Issue 1 2010
N. Niemenak
The detailed description of growth stages of useful plants followed by adequate codification facilitates communication between scientists and practicians if, for example, new findings of science have to be transferred to management procedures or if experiences made at one growing site have to be adapted to another. We describe the growth stages of the worldwide species of cacao trees (Theobroma sp.) to prepare the basis for production management, comparisons of epidemiological studies of disease, of growth patterns under different environmental factors and of genetically clone specific parameters. The codification follows the ,extended BBCH (BBCH, Biologische Bundesantalt, Bundessortenamt and CHemische Industrie, Germany) scale', a numerical system that differentiates between principal, secondary and tertiary growth stages. Each growth stage presented from seed germination to crown development and harvest is correlated with general management practices. This scale will be of great help to cacao growers and scientists around the world for better communication, more efficient planning of management practices and experiments. [source]