Field Guide of Discovery-based Exercises for - Aseanipm ...

Exercise No. 6.06 228
PRUNING AS AN INSECT PEST AND DISEASE
MANAGEMENT STRATEGY FOR ORGANIC VEGETABLE
PRODUCTION
BaCKGroUND aND raTIoNalE
Regular pruning usually reduces height and yield of a
plant, and changes its general configuration. The increased
vegetative growth that occurs after pruning does not
compensate for decreased photosynthetic area. The new
leaves that develop may be larger but fewer than the removed
leaves. It is, however, marketable yield that counts and not
total yield 229 . Therefore, an organic vegetable farmer has to
338
Field Guide of Discovery-based Exercises for Organic Vegetable Production
when is this exercise most
appropriate?
ɶ In FFS, TOT, and
VST sessions, at any
appropriate stages of
all organically-grown
vegetables in learning
field; and/or
ɶ When farmers want to
learn improved pruning
practices from other
farmers for any vegetable
crop.
decide on the amount of pruning to be done that will result in favorable effects and yet will not
reduce marketable yield.
In both conventional and organic vegetable production, pruning may also be practiced as a strategy
for pest and disease management. In some twig borer-infested solanaceous vegetables, pruning
is accomplished on affected plant parts to prevent twig borer larvae from further developing into
adults thereby drastically reducing pest population. In some instances, satisfactory disease control
can be achieved by simply removing diseased plant parts. For example, lower leaves of bean rustaffected
legume vegetables are pruned to reduce disease infection. Late blight-affected potato
leaves are pruned to prevent pathogen from reaching tubers 230 .
Conventional and organic vegetable farmers, particularly in the Cordilleras, had many other
innovative pruning practices that should be shared with other farmers in FFSs to continuously
improve their current best pruning practices. The foregoing exercise was specifically designed for
this purpose.
228 Adapted from Callo, Jr., D.P., L.B. Teofilo, and H.A. Tauli (eds). 2002. Field Guide of Discovery-based Exercises for Vegetable IPM, Volume II. SEAMEO
Regional Center for Graduate Study and Research in Agriculture (SEARCA), Los Baños, Laguna, Philippines. pp 277-279.
229 Bautista, O.K. (ed). 1994. Introduction to Tropical Horticulture. 2 nd Edition. SEAMEO Regional Center for Graduate Study and Research in Agriculture
and University of the Philippines Los Baños, College, Laguna, Philippines. pp385-399.
230 Quebral, F.C. 1988. What one should know about plant diseases. University of the Philippines Los Baños, College, Laguna, Philippines. pp18-20.