Rehabilitation Approach for quick and sustainable regain in cocoa production in declining full sun plantations

In Malaysia an intensively managed high input full sun cocoa plantation can reach high yields of 1.5 to 2 t dry beans per ha. Following a high production period of 10 years the yields often decrease markedly. Focusing on leading depleted cacao plantations sustainably back to full production a research project was initiated in June 2011 using a diversification approach with agroforestry systems. The experimental site is located on a large commercial farm in the humid tropical lowlands of peninsular Malaysia, in the region of Kuala Lipis. In a field trial with a strip-split-plot design, three different production systems, mainly characterised by diversification levels (mono culture to high diversity agroforestry) and accordingly different external input levels (high to low), are compared under two tree age conditions: newly planted and old rehabilitated cocoa trees, after the removal of the original canopy back to the leader structure. The existing twenty-two-year-old plantation with the original canopy and a high input level serves as control treatment. When cacao yields decline after the initial high production period trees are often replanted. This results in a non-productive phase lasting several years before the young trees start to develop pods and even longer before yields reach a remunerative level. Rehabilitating old low producing trees on the other hand, as practised in the present experiment, is expected to re-establish higher yields more quickly than re-planting. The first full harvest in the trial started in September 2012, 15 months after the rehabilitation pruning. Between September 2012 and March 2013 (main harvest) an average of 462 kg dry beans per ha were harvested in the control treatment. The yields of the common practice treatment already amounted to 24.9 % of the control. This is a very promising result, especially in view of the development of young trees which will take at least another year before the first pod development. Yields in the agroforestry systems increased less quickly as tree development under shade and with lower fertiliser input is inherently slower

Successful rehabilitation approach for sustainable regain in cocoa production systems in South-East Asia

In Malaysia an intensively managed high input full sun cacao (Theobroma cacao L.) plantation can reach high yields of 1.5 to 2 t dry beans per ha. Following a high production period of 10 years the yields often decrease markedly. Focusing on leading depleted cacao plantations sustainably back to full production a research project was initiated in June 2011 using a diversification approach with agroforestry systems. The experimental site is located on a large commercial farm in the humid tropical lowlands of peninsular Malaysia, in the region of Kuala Lipis. In a field trial with a strip-split-plot design, three different production systems are compared under two tree age conditions: newly planted and old rehabilitated cacao trees, after the removal of the original canopy back to the leader structure. The examined production systems are: i) high external inputs in a mono crop full sun system representing the common practice of large cacao plantations in South-East Asia (COM); ii) medium level of external inputs in an agroforestry system of low diversity focusing on leguminous and timber trees (AF LD); iii) low external inputs in an agroforestry system of high diversity and high density shade trees including annual crops and fruit trees (AF HD). The existing twenty-two-year-old plantation with the original canopy and a high input level serves as control treatment (REF). When cocoa yields decline after the initial high production period trees are often replanted. This results in a non-productive phase lasting several years before the young trees start to develop pods and even longer before yields reach a remunerative level. Rehabilitating old low producing trees on the other hand, as practiced in the present experiment, is expected to re-establish higher yields more quickly than re-planting. The first full harvest in the trial started in September 2012, 15 months after the rehabilitation pruning. Between October 2012 and June 2013 (main harvest) an average of 471.2 kg dry beans per ha were harvested in the control treatment. The yields of the common practice treatments already amounted to 41.6 % of the control. This is a very promising result, especially in view of the development of young trees which will take at least another year before the first pod development. Yields in the agroforestry systems increased less quickly as tree development under shade and with lower fertilizer input is inherently slower

Evaluation of attract-and-kill strategy for management of cocoa pod borer, Conopomorpha cramerella, in Malaysia cocoa plantation

In South-East Asia, cocoa production is dramatically affected by cocoa pod borer (CPB) infestations. As an alternative tool to chemical control, the efficacy of attract-and-kill strategy (CPB sex-pheromone as attractant and Delta trap without sticky liner sprayed with cypermethrin solution as killing station) was evaluated and compared with current standard CPB management approach as control treatment during two main cocoa harvest seasons in Malaysia (with 100 mu g and 33.3 mu g CPB-pheromone loading per station, respectively). In both seasons, attract-and-kill strategy was highly effective at reducing male flight activity (p < 0.05) in attract-and-kill plots comparing with standard CPB management plots. For the percentage of CPB-infested pods, the attract-and-kill strategy (100 mu g) was as good as the conventional pesticide spray applications of cypermethrin (p = 0.083) in first season. However, it was significantly (p = 0.021) reduced in the second season with lower pheromone loading (33.3 mu g), indicating that this semiochemical based strategy is far superior to and more feasible than the currently applied conventional synthetic pesticide treatment and is therefore a good alternative in CPB integrated pest management

Biocontrol of vascular streak dieback (Ceratobasidium theobromae) on cacao (Theobroma cacao) through induced systemic resistance and direct antagonism

Vascular streak dieback (VSD), caused by Ceratobasidium theobromae (P.H.B. Talbot & Keane), has a considerable impact on cacao (Theobroma cacao L.) production in Southeast Asia. Two biocontrol experiments were set up to explore alternatives to ineffective chemical control of VSD. The effects on VSD development of (i) Trichoderma harzianum, superficially applied to leaves of mature cacao plants, and (ii) an inoculation with fungal (Trichoderma asperellum) and bacterial (Bacillus sp., Pseudomonas sp. and Enterobacter spp.) elicitors of systemic resistance in young cacao plants, were tested. After three months, cacao leaves treated with T. harzianum exhibited a significantly (p < .05) lower disease score compared to the untreated control leaves, with no significant differences or interaction effects between three cacao clones tested. Six months after inoculation of cacao seedlings with elicitors, a significant (p < .05) effect on the number of VSD-affected leaves per plant was evidenced on seedlings treated with Bacillus sp. and Enterobacter spp. After transplanting to the field (8 months after inoculation), both number of VSD-affected leaves per plant and number of VSD-affected leaves per branch per plant were significantly (p < .05) lower as compared to control plants following inoculation by all bacterial elicitors tested, with no significant differences in the VSD controlling effect observed between the different bacterial elicitors tested. T. asperellum did not show potential as an elicitor of systemic resistance in our experiment. More research is needed on the lasting effect of biocontrol treatments, as well as on their economic and ecological sustainability

Geometric isomers of sex pheromone components do not affect attractancy of Conopomorpha cramerella in cocoa plantations

The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen), sex pheromone was previously identified as a blend of (E,Z,Z)- and (E,E,Z)-4,6,10-hexadecatrienyl acetates and corresponding alcohols. These pheromone components were synthesized by modification of an existing method and the relative attractiveness of synthetic blends that included different levels of non-target pheromone components and chemical purities was tested in a cocoa field using Delta traps. Male captures were not significantly different among traps baited with pheromone blends containing 5% to 47% (based on four identified pheromone components) of other geometric acetates [(E,Z,E)-, (Z,Z,Z)-, (Z,E,Z)- and (Z,E,E)-4,6,10-hexadecatrienyl acetates], indicating that C.cramerella males did not discriminate among the pheromone components and other geometric isomers in the blends. Therefore, neither antagonistic nor synergistic effects from other pheromone geometric isomers were observed. The modified synthetic pathway offers the prospect of more economical production of CPB sex pheromone. During 17weeks when C.cramerella monitoring coincided with the main cocoa pod harvest period in 2013-2014, CPB trap catch data from some blends showed a good correlation with the number of pods with C.cramerella infestation symptoms