Several strains of insects that infest
the Brazilian rice fields are similar to
strains that occur in other regions around
the globe, some of them with equal, big-
ger or smaller potential for damage. It
is the case of the rice stem borer, high-
ly damaging in Asia, but of secondary
importance in Brazil. “Remarkably, in
that continent there are locusts that, be-
sides directly damaging the rice plants,
are vectors of viral diseases, a problem
that does not exist in Brazil”, explains re-
searcher José Francisco da Silva Martins,
fromEmbrapa Temperate Climate.
Should any exotic species (quarantin-
ary rice pest) enter Brazil, the official or-
gans responsible for solving the problem,
have already adopted the necessary mea-
sures. According to the agronomist, it is
understood that a future strategy of the
rice sector, in search of higher competi-
tiveness, implies in maximizing the use of
information about the IPM, so as to avoid
any dependence on chemical insect con-
trol, making use of the economic, toxico-
logical, environmental and rice quality ad-
vantages, resulting fromthis attitude”.
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Through the rice fields around the world
H
istorically a complex of pest in-
sects occurs in rice farming in
Brazil,withthepotentialtocause
quantitative productivity losses
ranging from 20% to 30%, both
in irrigated fields in the flooding system in the
Southand in the fields of dry land rice inhigh-
lands,intheCenter-West.Damagesareequal-
ly qualitative. Termites, plant lice and weevil
larvae(rootmaggot)damageplantsandroots
in the initial and vegetative stage of the crop.
Worms alsoattack youngplants andpanicles,
whilstbugsdamagestalksandgrains.
According to agronomist José Francis-
co da Silva Martins, researcher with Embra-
pa Temperate Climate, in Pelotas (RS), in the
control of these insects, insecticide applica-
tions predominate, in the treatment of the
seeds or through foliar spraying, based on
the calendar, even in areas with no history
of outbreaks, or where the population has
not yet reached the level of control, capable
of causing economic damage. “Example of
chemical control that should be rethought
is the use of seeds treated in fields estab-
lished on slopes for the control of rice wa-
ter weevils (Oryzophagus oryzae), where a
huge portion of the area is infested with the
insect, as irrigationwater does not accumu-
late on the surface of the soil”, he explains.
For the master in Entomology, other
methods for Integrated Pest Management
(IPM) in rice fields, whose introduction could
mitigatetheuseofinsecticides,shouldbecon-
sidered. In his view, based on the association
between theperiod thepest occurs in the rice
field, the level and type of damage, the dif-
ficulties in controlling the problem(although
through chemical products) and the toxico-
logical and environmental implications, the
ricestinkbug(Tibracalimbativentris)andthe
smallricestinkbug(Oebaluspoecilus)areev-
identlythemajorinsect-peststhatneedtobe
focusedonby the rice farmers.
“The rice stalk stink bug, in spite of be-
ginning its attacks at the growing stage, is
CONTROLOFINSECTSINRICEGROWING
AREASMAkESITMANDATORyFORTHE
FARMERSINTHEENTIRECOUNTRyTORESORT
TOINTEGRATEDPESTMANAGEMENT(IPM)
generally controlled with a mix of insecti-
cides and fungicides, applied at blossom-
ing time, when the rice plants are higher,
and most of the insects are established in
the lower portion of the plant, between the
stalks, and are hardly reached by the mix-
tures”, he explains. The rice stink-bug, more
frequent in the tropical region of Brazil, oc-
curs close toharvest time, causingquantita-
tive and qualitative damages, consisting of
grain spots anddistortions. In this case,Mar-
tins maintains that sprayings, in case the
level of control has not been reached, will
only increase the risk of insecticide residue
accumulations in the kernels, which turns
out to be less desirable in light of the expan-
sion of the international ricemarket.
With an eye on improving the IPM for in-
sects, the researcher stresses that research
organshavereleaseddataonthewaythein-
sects disseminate throughout the rice fields,
population levels of control, effects stem-
ming from cultural practices and correct
insecticide handling. They also reinforce
questions related to cultivar resistance, bio-
logical control, pheromones, diagnoses and
prediction methods, among others. “This is
important information, so far little used by
the rice growing sector”, he comments.
Targetedby
science
Research organs furnish data on the manner insects disseminate
Inor Ag. Assmann
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