Weed control program should be environmentally benign and cost-effective so that reduced herbicide use can help meet
these goals. Field trials were conducted to assess the bio-economic and qualitative impact of reduced doses (25 and 50% of
label dose) of a postemergence pyrimidinyloxybenzoic acid herbicide (bispyribac-sodium) applied alone or in combination
with multipurpose tree (eucalyptus [
Eucalyptus camaldulensis
Dehnh.], mango [
Mangifera indica
L.], and mulberry
[
Morus alba
L.]) water extracts in direct seeded rice (
Oryza sativa
L.) fields. The label dose of bispyribac-sodium and
penoxsulam along with weed control were included for comparison. Tank mixing of multipurpose tree water extracts with
reduced herbicide doses accounted for > 55% suppression in weed density and > 75% in dry weight; they were quite higher
than those recorded for the same herbicide doses used alone. A combination of these extracts with 50% reduced dose of
bispyribac-sodium improved rice yield and quality attributes similar to the label dose of this herbicide. Despite the higher
net benefits associated with label herbicide dose, the maximum marginal rate of return was achieved with a tank mix of 25%
label herbicide dose with multipurpose tree water extracts.
