Use of adjuvant and allelopathic plant extract to minimize the herbicide dose for controlling parthenium (Parthenium hysterophorus L.) in okra (Abelmoschus esculentus)

Abstract

Herbicide use in vegetables poses serious
ecological and health hazards. To identify chemical
strategy for minimizing herbicide doses with the use of
adjuvant and allelopathic plant extract for controlling
parthenium weed in okra, two-year field studies were
undertaken at experimental area of College of Agriculture,
University of Sargodha, Punjab-Pakistan during the
summer seasons of years 2018 and 2019. The experimental
treatments were a pre-emergence application of
pendimethalin (495 g a.i. ha-1
), post-emergence
applications of metribuzin and halosulfuron at their full
(518 g a.i. ha-1
and 37 g a.i. ha-1
, respectively) and 75%
doses alone and tank-mixed application with alkyl ether
sulfate (AES) adjuvant and aqueous extract of A. aspera
(AAE). The results indicated that among two herbicides,
the efficiency of halosulfuron was proved to be higher than metribuzin in terms of reducing parthenium dry weight and
getting higher okra pod yield. Among two herbicides,
halosulfuron showed greater enhancement in its efficacy by
addition of adjuvant as compared to that shown by metribuzin.
Halosulfuron full and 75% dose alone and in mixture with
AES and AAE caused significantly the highest reduction in
parthenium weed dry weight (up to 78%), while the highest
increases in plant height (up to 76%), number of leaves
(443%), number of pods (up to 256%), pod length (up to 66%)
and pod yield (up to 82%) of okra in comparison to control.
The reduced dose of halosulfuron in mixture with AES
adjuvant showed the same performance as shown by its full
dose alone in reducing weed density and dry weight and
increasing pod yield of okra. It can be concluded that the
halosulfuron dose can be reduced up to 25% if AES adjuvant
was tank-mixed in it to obtain the same efficiency as with its
full dose without compromising okra yield. © 2020
Department of Agricultural Sciences, AIOU