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

Exercise No. 4.14 155
FIELD-COLLECTION AND USE OF GREEN AND WHITE
MUSCARDINE FUNGI FOR LEPIDOPTEROUS PESTS
MANAGEMENT IN ORGANICALLY-GROWN VEGETABLES
BaCKGroUND aND raTIoNalE
Naturally occurring predators, parasitoids, and insect pathogens
attack eggs, larvae, nymphs, and adults of lepidopterous
insect pests of organically-grown vegetables. Among insect
pathogens, the most common are green (Metarhizium anisopliae
[Metchnikoff] Sorokin) or GMF and white (Beauveria bassiana
[Balsamo] Vuillemin) or WMF muscardine fungi. Among
others, they are known to attack larvae of many lepidopterous
pests of organically-grown vegetables. These insect pathogens
are described below 156 :
Green muscardine fungus or GMF is a naturally-occurring
insect pathogen that attacks more than 200 insects. The fungus
has cylindrical conidiogenous cells. Inside these cells are
232
Field Guide of Discovery-based Exercises for Organic Vegetable Production
when is this exercise most
appropriate?
ɶ In FFS, TOT, and VST
sessions, as follow-up or
integral part of topic on
‘Biological Control of
Insect Pests’; and
ɶ When farmers want to
learn some innovative
ways of using green
(Metarhizium anisopliae)
or GMF and white
(Beauveria bassiana)
or WMF muscardine
fungi as biological
control agents against
lepidopterous pests
of organically-grown
vegetables.
powdery masses of dark green to yellow-green columns of conidia that arise from white mycelium.
The conidia are > 9 µm long and are cylindrical with a slight central narrowing. They form very
long and laterally adherent chains. The spores are shaded green. GMF spores land on host’s body
and high humidity favors its growth. During its development, fungus consumes its host’s contents.
When host dies, fungus emerges as a white growth and then turns dark green with age. The spores
are spread by wind or water to new hosts.
White muscardine fungus or WMF is a naturally-occurring insect pathogen commonly used for
insect pest control worldwide. The fungus forms white powdery conidial masses that are globose
to broadly ellipsoid. They measure 2.5-3.5 µm. They are produced on sympodial conidiogenous
cells present on hyphae arising from mycelium mat. These cells are globose to flask-shaped, 2-3 x
2-4 µm with dented zigzag-shaped rachis that reaches up to 20 µm. During development, fungus
uses soft tissues and body fluids of host. The growth of WMF requires conditions of prolonged high
moisture for airborne and waterborne spores to germinate. When ready to produce chalky-white
spores, fungus grows out of host’s body.
155 Adapted from Callo, Jr. D.P., A.G. Castillo, and C.A. Baniqued (eds). 2001. Field Guide of Discovery-based Exercises for Corn Production. SEAMEO
Regional Center for Graduate Study and Research in Agriculture (SEARCA), College, Laguna, Philippines. pp298-300.
156 IRRI. 2008. Insect Pathogens. As cited in: http://www.knowledgebank.irri.org/beneficials.