Ecology and management of an exotic weed Phalaris minor - Invasive Plants: Ecological and Agricultural Aspects - page 162

P. minor is a bigger problem in wheat-rice cropping systems compared to
where rice is not sown after wheat. Wheat-rice cropping systems are prevalent
in Punjab and Haryana where P. minor has been selected for herbicide resistance
[1, 22]. Anaerobic conditions due to cultivation of lowland rice may contribute
to maintaining the viability of P. minor seeds. Parashar and Singh [28] found
that P. minor seeds enter into secondary dormancy under anaerobic conditions.
It is hypothesized that P. minor seeds have potential to tolerate oxygen stress due
to synthesis of secondary metabolites that change membrane permeability.

Management

Herbicide-resistant weed species are a serious threat to agriculture, and their
management is receiving considerable attention from researchers and industry
[29]. Although manual removal of P. minor still occurs (Fig. 1c), farmers rely
heavily on chemical control (Tab. 2). Isoproturon has been used to control P.

Table 2. Herbicides recommended for P. minor control

Herbicide Mode of action Chemical class Time of application

Metsulfuron (Escort/Ally) ALS inhibitor Sulfonylurea Pre- & Post-emergence

Sulfosulfuron (Leader) ALS inhibitor Sulfonylurea Pre- & Post-emergence

Tribenuron (Express) ALS inhibitor Sulfonylurea Post-emergence

Isoproturon (Techical) PS II inhibitor Phenylurea Pre- & Post-emergence

Chlorotoluron PS II inhibitor Phenyl urea Pre- & early post-

emergence

Metribuzin (Sencor) PS II inhibitor Triazine Pre- & Post-emergence

Atrazine (AAtrex) PS II inhibitor Triazine Post-emergence

Terbutryn (Prebane) PS II inhibitor Triazine Pre- & Post-emergence

Metaxuron (Dosanex) PS II inhibitor Subsituted urea Pre- & Post-emergence

Methabenthiazuron (Tribunil) PS II inhibitor Subsituted urea Post-emergence

Clodinafop (Topik) ACCase inhibitor Aryloxyphenoxy Post-emergence

propionate

Diclofop (Hoegrass) ACCase inhibitor Aryloxyphenoxy Post-emergence

propionate

Fenoxaprop-P ACCase inhibitor Aryloxyphenoxy Post-emergence

(Cheetah super, Whip) propionate

Tralkoxydim (Grasp) ACCase inhibitor Cyclohexanedinone Post-emergence

Pendimethalin (Stomp) Microtubule- Dinitroaniline Pre-emergence

assembly inhibitor

Nitrofen PPO inhibitor Diphenylether Pre-emergence or

pre-plant incorporated

ALS, acetolactate synthase; PS, photosystem; ACCase, acetyl-CoA carboxylase; PPO, protopor-
phyrinogen oxidase