de Bie, Kees
bud-dormancy breaking agent, e.g. potassium nitrate (as a spray). The technology
was successfully used to produce off-season fruit at high gross-margins.
Pruning of mango trees is not common, but practiced in Phrao to remove
branches that are affected by stemboring caterpillars. Pending on its timing,
pruning induces a new growth flush, and possibly fruits the year after.
Weeding by tractor is a management aspect that indirectly seems to influence the
hormonal balance of trees. Weeding by tractor is done by ploughing-in the weeds
and results in cutting sub-surface mango roots; it must thus be labeled as root-
pruning. This practice restricts water and nutrient uptake and if done at the
appropriate time in the tree’s physiological cycle, results in more prolific flowering
and better yields (Subhadrabandhu 1990, Sauco 1989).
SPRAYING PESTICIDES
In Thailand, the price of pesticides is high so that most growers cannot afford
adequate pest control (Polprasid 1986). Only Azodrin (monocrotophos) proved
effective, even when not applied by motor sprayer. The high efficiency of motor
sprayers to apply pesticides into the canopy is proven beyond doubt.
Bf in fully grown orchards weeding takes place by
tractor
Ef the ability exists to apply supplementary irrigation
water
L1If the top-soil has a relatively high pH
El Combined effect of 'pruning* motor spraying'
Elf Azodrin is used to control caterpillars
Li Combined effect of 'location'
Mango Yield '000 Bath/ha
Biennial bearing behavior of mango
Ed Actual average yield
45 Orchards
Figure 13. Yield constraints of mango orchards in Phrao (1993
season).
The specialized management requirements of mango orchards require not only a
high level of knowledge and experience by farmers but also a well-informed
extension service. Close(r) collaboration between this service and researchers of
universities and research stations is strongly recommended.
338 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
