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

Section 5 • Integrated Disease Management
INTRODUCTORY EXERCISES ON DISEASES
In a previous refresher course 171 mentioned earlier, field walks, observations and collection of
diseases and physiological disorders of crucifers (e.g., cabbage and cauliflower), parsley (e.g.,
carrot and celery), legumes (e.g., snap bean and garden pea), cucurbits (e.g., cucumber, chayote,
and zucchini), and solanaceous vegetables (e.g., potato, tomato and bell pepper) were similarly agreed
upon by participants as initial step in field diagnosis of vegetable diseases. This will be followed by
sorting and identification of collected specimens by participants in small groups and validation with
technical experts in a big group session. Again, participants together with technical experts should
summarize outputs of said session by coming up with a list of most distinguishing characteristics for
field identification of vegetable diseases 172 and physiological disorders 173 as follows:
• Virus Diseases. The general symptoms are: (a) leaf discoloration, (b) stunting, (c) leaf rolling
or twisting, and (d) vein clearing;
• Bacterial Diseases. The most common symptoms are: (a) maceration or disintegration of
tissues, (b) ‘water-soaked’ appearance, and (c) ‘foul’ odor;
• Fungal Diseases. The general symptoms are presence of: (a) ‘cottony-like’ and (b) ‘dry’
appearances (e.g., leaf spots) of infected plant parts;
• Nematodes (or the ‘unseen enemy’). The general symptoms are: (a) gall formation in root
system, (b) root necrosis (e.g., branching), and (c) gall formation within root system (in contrast
to nodules which are formed outside root system); and
• Physiological Disorders. The usual symptoms are malformations caused by: (a) non-infectious
organisms, (b) nutrient deficiencies or toxicities, and (c) chemical injuries or toxic residues.
171 Binamira, J.S. 1998. A Consultant’s Report: Refresher Course for Trainers of IPM in Crucifers and Other Highland Vegetable Crops. Cordillera Highland
Agricultural Resources Management Project, Department of Agriculture, CAR Regional Field Unit, Baguio City, Philippines. pp15-22.
172 Milagrosa, S.P. 1998. As cited in: 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. 366p.
173 Balaki, E.T. 1998. As cited in: 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. 366p.
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