The correction of boron deficiency in cacao in Ecuador

Boron deficiency has been shown to exist on certain soils in Ecuador, cacao showing leaf symptoms and giving low yields. The effect of three levels of boron supplied as a monthly foliar spray of Solubor has been studied. Boron treatments led to an increase in the dry weight of the leaf and to increased contents of nitrogen and boron as a percentage of dry weight. The expression of leaf symptoms was reduced. Pollen germination, growth of the pollen tube, fruit set and persistence of the fruit were all increase. An increase in yield of the trees was found only with artificial pollination. Natural pollination on the site appears to be low, the result, it is thought, of a shortage of insect pollinators