Prediction of pest pressure on corn root nodes: the POPP-Corn model
Prediction of pest pressure on corn root nodes: the POPP-Corn model
Annika Agatz 0 1 2 3
Roman Ashauer 0 1 2 3
Paul Sweeney 0 1 2 3
Colin D. Brown 0 1 2 3
0 Environment Department, University of York , Heslington, York , UK
1 & Annika Agatz
2 Communicated by M. Traugott
3 Syngenta , Jealott's Hill, Bracknell , UK
A model for the corn rootworm Diabrotica spp. combined with a temporally explicit model for development of corn roots across the soil profile was developed to link pest ecology, root damage and yield loss. Development of the model focused on simulating root damage from rootworm feeding in accordance with observations in the field to allow the virtual testing of efficacy from management interventions in the future. We present the model and demonstrate its applicability for simulating root damage by comparison between observed and simulated pest development and root damage (assessed according to the node injury scale from 0 to 3) for field studies from the literature conducted in Urbana, Illinois (US), between 1991 and 2014. The model simulated the first appearance of larvae and adults to within a week of that observed in 88 and 71 % of all years, respectively, and in all cases to within 2 weeks of the first sightings recorded for central Illinois. Furthermore, in 73 % of all years simulated root damage differed by \0.5 node injury scale points compared to the observations made in the field between 2005 and 2014 even though accurate information for initial pest pressure (i.e. number of eggs in the soil) was not measured at the sites or available from nearby locations. This is, to our knowledge, the first time that pest ecology, root damage and yield loss have been successfully interlinked to produce a virtual field. There are potential applications in investigating efficacy of different pest control measures and strategies.
Population model; Integrated pest management; Diabrotica; Node injury; Zea mays; Pest
-
•
The corn rootworm is a pest of international importance
in corn production due to larvae feeding on roots.
Deciding on the necessity for and optimal decision on
type of control measure is challenging because damage
and yield loss vary with region and season.
A model capable of predicting root damage specific to
region and season has been developed and provides a
powerful tool to support decision-making processes for
both provider and user of pest control measures.
Introduction
The corn rootworm Diabrotica spp. (Coleoptera:
Chrysomelidae) is a univoltine pest in corn [Zea mays
subsp. Mays (L.)] production which has become a pest of
international importance due to its presence in the USA,
Canada, Mexico and Europe
(Meinke et al. 2009)
. Yield
loss and expenses associated with rootworm damage
exceed costs of $1 billion per year in the USA alone
(Tinsley et al. 2015)
. Adult beetles lay eggs from the
middle of the summer to late autumn into the upper 30 cm
of soil
(Vidal et al. 2005)
. Eggs overwinter and develop to
new adults below ground over the summer to then emerge
from the soil, mate and lay eggs for the next growing
season. The larvae, which hatch from the eggs around early
summer, pass through three instar phases before pupation
and emergence as adult beetles
(Meinke et al. 2009)
. All
larval instars depend on foraging on corn roots for
successful development; this can cause substantial damage
which is manifested in reduced growth and lodging of corn
plants
(Meinke et al. 2009)
. The damage caused depends
on a variety of factors including, but not limited to, pest
pressure, planting time, row spacing at planting, climate
and soil type.
Damage control strategies for corn rootworm include the
use of crop rotation, the use of Bt corn and the application
of plant protection products against adults as foliar
application and/or against larvae as seed treatment or soil
application
(Hodgson 2008)
. Both the need for damage
control measures and the effectiveness of those measures in
controlling pest populations within economic thresholds
will vary in space and time. This presents challenges to
farmers in deciding on the necessity for and optimal
decision on type of control measure, and to assessors and
developers of control measures to judge the overall
(region- and season-independent) efficacy of a control
measure. The development of a temporally and spatially
explicit population model which supports the prediction of
root damage and yield loss that is specific to region and
season could thus be a vital step towards the provision of a
powerful tool to support decision-making processes for
both provider and user of pest control measures.
There has been extensive research on simulation of corn
rootworm including the development of modelling tools to
predict temporal egg hatch and adult emergence
(Nowatzki
et al. 2002; Schaafsma et al. 1991; Stevenson et al. 2008)
,
the development of cohort population models
(Elliott and
Hein 1991; Elliott et al. 1990; Mitchell and Riedel (...truncated)