Abstract:
The sunflower caterpillar
Chlosyne lacinia
saundersii
(Lepidoptera: Nymphalidae) is
considered a major pest in sunflower, causing sever
e defoliation and, thus, threatening
production of oilseed. Chemical control remains the
most widely used method for the
management of this defoliator. To manage insect pes
ts, there is a need to use substances of
low toxicity that are able to stimulate the plant t
o use its own defense mechanisms.
Therefore, in this study, we evaluated the inductio
n of resistance by silicon (Si) and
acibenzolar-S-methyl (ASM) against
C. lacinia saundersii
in sunflower plants. The
bioassay was conducted in a completely randomized d
esign using 4 treatments and 10
replicates. The treatments were: (1) Si; (2) ASM; (
3) Si+ASM, and (4) the control. The
biological parameters of the caterpillar and the ac
cumulation of Si and lignin in plants
were evaluated. The application of resistance induc
ers reduced weight of the caterpillars
10 and 15 days of age. The use of Si alone or Si+AS
M promoted the accumulation of this
element; however, only ASM increased lignin content
in plants. Negative correlations
between the silicon content and larval weight and b
etween the silicon content and lignin
content were observed. Therefore, the application o
f silicic acid or ASM can inhibit the
development of
C. lacinia saundersii
, conferring a resistance in plants attributable to
the
accumulation of silicon and lignin, thus serving as
an alternative approach that may
potentially be integrated into the management of th
is key pest in sunflower crops.
Keywords:
Benzothiadiazole,
Chlosyne lacinia saundersii
,
Helianthus annuus
L., Integrated
pest management, Silicic acid.
