Agriculture Reference
In-Depth Information
8.3.5 HIGH TEMPERATURE INCREASE IN DISEASES, INSECT
PESTS AND WEEDS
As temperature increases, the insect-pests will become more abundant
through a number of interrelated processes, including range extensions
and phenological changes, as well as increased rates of population devel-
opment, growth, migration and overwintering. The climate change is
likely to alter the balance between insect pests, their natural enemies
and their hosts. The rise in temperature will favor insect development
and winter survival. Rising atmospheric carbon dioxide concentrations may
lead to a decline in food quality for plant-feeding insects, as a result of
reduced foliar nitrogen levels. The epidemiology of plant diseases will be
altered. The prediction of disease outbreaks will be more difficult in peri-
ods of rapidly changing climate and unstable weather. Environmental
instability and increased incidence of extreme weather may reduce the
effectiveness of pesticides on targeted pests or result in more injury to
nontarget organisms.
• Insect pest will increase with increase temperature and pest activity
period will be longer for example DBM in cauliflower and
Heliothis
in
tomato.
• There will be negative growth of predator like
Trichoderma
• Weed and pest will have opportunity to spread where they have cur-
rently unable to establish because of temperature constraints, for ex-
ample, white fly.
• Poor effectiveness of biological pesticides, NPV for tomato (effec-
tive under cool moist condition).
8.3.6 LOW TOLERANCE IN VEGETABLES
The cultivated tomato genotype (
Solanum lycopersicum
earlier known as
Lycopersicon esculentum
L.) displays limited growth and development at
temperatures under 12ºC (Hu et al., 2006). At temperatures between 0 and
12ºC, plants are damaged by chilling stress. The severity of damage is
proportional to the length of time spent in this temperature range.
