Evaluation of Witches’ broom disease severity for cacao/plantain intercropping systems under four spatial arrangements, 2006-2007.

摘要

Five intercropping systems of plantain with cacao were developed to test the effect of intercropping on the incidence of witches’ broom disease. The five spatial arrangements consisted of three intercropped systems and one cacao and one plantain monoculture, each consisting of four replications planted in a randomized complete block design. Each plot/replication has an area of 864 m2, with an average of seventy five plants per crop/plot. For cacao an Ecuadorian clone (EET-103) of the national type was planted as a four month-old clonally rooted plantlet in Apr 06. Rooted plantain suckers of cultivar cv. Barraganete were planted at the same time. The plots were managed following standard IPM practices including mechanical control of weeds, nutritionbased on previous soil analysis and plant requirements, phytosanitary pruning, etc. The five spatial arrangements were: CDR+PDR = cacao double row (833 plants/ha) + plantain double row (1111 plants/ha); CSR+PSR = cacao single row + plantain single row (954 plants/crop/ha); CD + PD = cacao diamond (943 plants/ha) + plantain diamond (1095 plants/ha); SC = single cacao in square (1111 plants/ha) and SP = single plantain in square (1111 plants/ha.). The diamond planting arrangement separates each cacao plant both in row, and across rows with a plantain, and similarly separates each plantain with a cacao. Treatments were evaluated for the witches’ broom incidence in the mid-rainy season (Mar 07). The number of symptomatic axillary shoots, terminal shoots, and flower cushions born on the stems were recorded. By the time of the evaluation, the plantains were 4 times the height of the cacao plants (1 to 1.5 m) and provided a dense overstory to the much smaller cacao during the rainy season.