Impacts on Insect and Mite Pests - Climate Resilient Agriculture for Ensuring Food Security - page 122

Table 7.3 (continue d)

Herbivore species Host species Effects

Order Comments

ÿ

Hymenoptera Aphidius matricariae (green

peach aphid parasitoid)

Poa annua (grass)

Lepidoptera Pseudoplusia includens

(soybean looper)

Glycine max (soybean) − Caterpillars

generally eat
more to
compensate, but
enhanced plant
growth results in
little net effect

ÿ

Trichoplusia ni (cabbage
looper)

Phaseolus lunata (lima
bean)

Spodoptera eridania (southern
armyworm)

Mentha piperita
(peppermint)

ÿ

Spodoptera frugiperda (fall
armyworm)

Festuca arundinacea (tall
fescue)

ÿ

Pectinophora gossypiella
(pink bollworm)

Gossypium hirsutum
(upland cotton)

ÿ

Helicoverpa armigera (cotton
bollworm)

Gossypium (cotton) +

A warmer climate in temperate regions may
result in changes in geographical distribution,
increased overwintering (i.e., more insects sur-
vive the winter), changes in population growth
rates, increases in the number of generations,
extension of the development season, changes in
crop-pest synchrony, changes in interspecifi c
interactions, and increased risk of invasion by
migrant pests (Bale et al. 2002 ). In Japan, warmer
climate led to the northward migration of the
green stinkbug ( Nezara viridula ), a major agri-
cultural pest damaging soybean, rice, cotton, and
many other crops (Musolin 2007 ).
Geographical distribution of insect pests con-
fi ned to tropical and subtropical regions will
extend to temperate regions along with a shift in
the areas of production of their host plants, while
distribution and relative abundance of some
insect species vulnerable to high temperatures in
the temperate regions may decrease as a result of
global warming. These species may fi nd suitable
alternative habitats at greater latitudes.
An increase of 1 and 3 °C in temperature will
cause northward shifts in the potential distribu-
tion of the European corn borer, Ostrinia nubila-
lis , up to 1,220 km, with an additional generation
in nearly all regions where it is currently known
to occur (Porter et al. 1991 ).
Diamondback moth, Plutella xylostella , over-
wintered in Alberta in 1994 (Dosdall 1994 ), and
if overwintering becomes common, the status of

7.5 Expansion of Geographical

Distribution

Climate change will have a major effect on geo-
graphic distribution of insect pests, and low tem-
peratures are often more important than high
temperatures in determining geographical distri-
bution of insect pests (Hill 1987 ). Increasing tem-
peratures may result in a greater ability to
overwinter in insect species limited by low tem-
peratures at higher latitudes, extending their geo-
graphical range (Fig. 7.3 ) (EPA 1989 ; Elphinstone
and Toth 2008 ), and sudden outbreaks of insect
pests can wipe out certain crop species and also
encourage the invasion by exotic species (Kannan
and James 2009 ). Spatial shifts in distribution of
crops under changing climatic conditions will
also infl uence the distribution of insect pests in a
geographical region (Parry and Carter 1989 ).
Some plant species may be unable to follow the
climate change, resulting in extinction of species
that are specifi c to particular hosts (Thomas et al.
2004 ). However, whether or not an insect pest
would move with a crop into a new habitat will
depend on other environmental conditions such as
the presence of overwintering sites, soil type, and
moisture, e.g., populations of the corn earworm,
Heliothis zea , in North America might move to
higher latitudes/altitudes, leading to greater dam-
age in maize and other crops (EPA 1989 ).