Transcript C13_WCR_Diabrotica

FOOD QUALITY AND SAFETY
MODULE C13
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Integrated Pest Management for
WESTERN CORN ROOTWORM -WCR
(Diabrotica virgifera virgifera LeConte)
in Central and Eastern Europe
Background
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First detection of WCR (damage by larvae) in
Europe in 1992;
Rapid spread of the pest in Europe;
Jumping-spread movement beyond the
actual spread line;
Multiple transatlantic introductions of WCR.
Morphology of WCR
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Eggs: 0,5 mm; whitish-yellow; 15-20cm in the soil;
Larvae: 3 larval stages; 1,2 mm (L1)- 1,5 cm (L3);
whitish-yellow, black head capsule; soil, maize roots;
Pupae (pupa libera) 7,5 mm; whitish-yellow; non
moving stage in the soil;
Adults: 7,5 mm; yellow, with three black strips;
difference between males and females; active on
plants.
Life cycle of WCR
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Eggs overwinter
in the soil
L1
Adults die
L2
L3
Oviposition
Emergence
of adults
Source: S. Toepfer
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Pupae
Damage by WCR larvae
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Successful development of larvae (almost)
only on maize roots;
Maize root system damaged, plants will lodge
(goose-neck symptom);
WCR larval damage evaluation: Iowa 1-6
scale, node – injury scale.
Damage by WCR adults
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WCR adults are feeding on several plant species,
Feed on pollen of different crops;
Feed on maize leaves, silks and pollen;
Economic damage on maize plants due to silk
clipping;
Less fertilized ears and yield loss (quantity and
quality of kernels).
Monitoring of WCR
adults
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Purpose:
Evaluation of the
- presence of WCR adult population;
- potential for silk clipping;
- risk for next year larval damage (if not rotated).
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Tools/methods:
- Csalomon pheromone traps;
- yellow sticky traps (e.g. Pherocon AM);
- whole plant count.
IPM for WCR
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Cultural practices
Crop rotation field test plots for WCR
management (EU 5th Framework
project Hungary, 2000-2004)
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- Feeding and oviposition of females in maize,
successful larval development in subsequent year maize
CROP ROTATION;
- Field size/margins/surrounding of the field;
- Soil type, tillage system/weeds;
- Planting time/hybrid selection; BT maize (?);
- Production inputs (fertilizer, water, green manure).
LATE PLANTING: escape from taching period of the larvae
where temperature and rainfall allow
EARLY PLANTING: to allow root system development as soon
as possible where temperature and rainfall allow
IPM for WCR
FOOD QUALITY AND SAFETY
Biological methods:
- There are several antagonists and parasitoids
(entomopathogenic fungi, Nematodes, Diptera
spp.) and predators (praying mantis, ground
beetles, spiders, frogs and some birds) that
parasite or prey on WCR;
- It is still not defined to what extent these
predators are able to regulate the WCR
population.
FAO/ S. TOEPFER
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FAO/ P. HOFFMANN
IPM for WCR
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Chemical control:
Larvae: to prevent/decrease larval damage in given year
- seed treatment
- soil insecticide application at planting
Innovative control option:
Bt (rootworm resistant) maize hybrids
- widespread in USA
- under approval in Europe
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Adults: to prevent damage by silk clipping or to reduce egg
laying and next year larval damage
- foliar insecticide application
- high clearence ground sprayer
- aircraft/helicopter
- attract and kill (reduced insecticide rate+feeding
arrestant)
Farmers perspective?
FOOD QUALITY AND SAFETY
FARMERS AIM is to be able to MANAGE the pest on their
fields,
but
Management of the WCR on one field is not effective enough
so
COMMUNITY ACTION is needed,
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based on COMMON UNDERSTANDING.