Page 182 - FRUTAS DEL TRÓPICO

182 Frutas del trópico

inoculum of P. palmivora high into the canopy (Konam and Guest, 2002). Once in the canopy,
reservoirs of inoculum establish in cankers, infected flower cushions and mummified pods.

Disease management strategies focus on eliminating sources of primary inoculum, preven-

ting the movement of inoculum from the soil to the canopy, and reducing the production of

secondary inoculum via frequent and complete harvesting of pods, and the appropriate disposal

of pod mummies, infected pods and pod husks. Chemicals are widely recommended for Phyto-

phthora control, but their effectiveness is variable, particularly during high-disease pressure in

the wet season. The implementation of recommendations is typically yield —and price-sensiti-

ve. Protectant sprays of copper-based fungicides and metalaxyl at 3- or 4— weekly intervals are

frequently recommended, but rarely cost-effective (Guest et al., 1994; Opuku, 2000). Annual
trunk injections of the inexpensive inorganic salt potassium phosphonate are very effective aga-

inst P. palmivora in very wet areas of Papua New Guinea (PNG) (Guest et al., 1994).

Frosty pod (edited from Phillips-Mora and Wilkinson, 2007). Frosty pod is caused by the

basidiomycete, Moniliophthora roreri. It is the most destructive disease of cacao, but has the

narrowest geographic distribution of the major diseases. It remains restricted to western South

America, but recently spread throughout Central America, reaching Mexico in 2005; it will

almost certainly spread throughout South America once it is established on the eastern side of
the Andes (Phillips et al., 2006). Its resilient spores, which are produced in great numbers on

affected pods, and the high susceptibility of most cultivars, make frosty pod a most dangerous

disease (Ram, 1989).

Pods are the only organ of cacao that are affected. External symptoms include the death

of young fruit, small water-soaked lesions, deformation and premature ripening and chocolate-

colored spots. In advanced infections, the internal pod tissues appear to form a compact mass

surrounded by a watery substance. The chocolate-colored spots develop a layer of white

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