The influence of a natural commercial bio-stimulant, ComCat®, alone and in combination with a prototype natural product (SS) in the developmental phase was investigated by means of two trials in a six-year-old Opuntia ficus-indica (L) Mill. orchard during the 2003/2004 growing season. The main aim was to quantify the effect on cladode initiation, fruit yield and fruit characteristics. ComCat® showed an effect on fruit production, while SS induced the development of new cladodes, but had no stimulatory effect on fruit yield.  A combination of ComCat® and SS, in a 50:50 ratio, increased both fruit and cladode formation, while Kelpak, a commercial seaweed extract used as a positive control, enhanced fruit development, but had no significant effect on cladode initiation. ComCat® and SS applied in combination also produced the highest percentage of medium fruits in both trials. Statistical analysis showed that fruit length and fruit diameter correlated with fruit mass, but this was not affected by the treatments. Similarly, fruit mass and peel mass were correlated with pulp mass and this was also not influenced by any of the treatments. Two statistical models were developed to predict the influence of a) fruit length and diameter on fruit mass and b) peel mass and fruit mass on pulp mass, and showed a >50% accuracy, confirming the application potential of these models in the cactus pear industry.