Weed Management

Bayer, D. E.

doi:10.1007/978-1-4899-3754-4_8

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…Thus, finding an appropriate and effective way to eliminate undesirable plant species is crucially important. Generally, there are numerous methods of weeding, such as biological, chemical, manual, and mechanical. − Among these, herbicides are still widespread . Moreover, since the discovery of the concept of allelopathy , agrochemists have been investigating the effect of allelochemicals on weeds and crop plants to produce natural product herbicides. − Further, to discover new and effective weed killers, chemists have also formed derivatives of allelochemicals − to find selective and eco-friendly herbicides.…”

Section: Introductionmentioning

confidence: 99%

Herbicidal Activity of Flavokawains and Related trans-Chalcones against Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

2019

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Flavokawains have a broad spectrum of biological activities; however, the herbicidal activity of these naturally occurring chalcones has been less investigated. Flavokawains and their analogues were prepared by the Claisen–Schmidt condensation reaction between xanthoxyline (or aromatic ketones) and a variety of aromatic and heteroaromatic aldehydes. These compounds were then evaluated for their inhibitory effect against representative dicot and monocot plants. Among 45 synthetic chalcones, derivatives containing phenoxyacetic acid, 4-(N,N-dimethylamino)phenyl, N-methylpyrrole, or thiophenyl groups inhibited the germination and growth of Chinese amaranth (Amaranthus tricolor L.) with moderate to high degrees compared to commercial butachlor. For barnyardgrass (Echinochloa crus-galli (L.) Beauv.), most of the thiophenyl chalcones interrupted shoot and root emergence. This finding highlighted the importance of functional groups on the herbicidal activity of chalcones. The level of inhibition also depended on the applied concentrations, plant species, and plant organs. (E)-2-(2-(3-Oxo-3-(thiophen-2-yl)prop-1-enyl)phenoxy)acetic acid (14f) was the most active compound among 45 derivatives. This chalcone could be a promising structure for controlling the germination and growth of weeds. The structure–activity relationship results provide useful information about the development of active chalconoids as novel natural product-like herbicides.

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Section: Introductionmentioning

confidence: 99%

Herbicidal Activity of Flavokawains and Related trans-Chalcones against Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

2019

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“…In general, weed management practices vary widely depending upon climatic and environmental conditions as well as weed species. Overall, the main methods of weeding are manual, mechanical, chemical and biological controls respectively [ 3 , 4 , 5 ]. Among those methods, chemical control is one of the most popular procedures.…”

Section: Introductionmentioning

confidence: 99%

Inhibitory Effects of a Variety of Aldehydes on Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

2018

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Thirty-seven commercial aldehydes containing aliphatic chains and aromatic rings as well as heteroaromatic rings were evaluated for their inhibitory activities against Chinese amaranth (Amaranthus tricolor L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv). Polysorbate 80 (Tween® 80) was used as a surfactant and the research was preliminarily conducted at 400 μM of all aldehydes. Among these aldehydes, (E)-cinnamaldehyde (7) showed the greatest inhibitory effect on seed germination, shoot and root growth of Chinese amaranth by 54.55%, 75.53%, and 85.13% respectively. Similarly, (E)-crotonaldehyde (5), a related α,β-unsaturated aldehyde, inhibited the germination and seedling growth of the tested species at a high percentage. Apart from these two unsaturated aldehydes, no other aliphatic aldehydes had a harmful effect on Chinese amaranth. In terms of benzaldehyde (6), it had no effect on the tested plant; however, many of its derivatives displayed some inhibitory activity. Furthermore, for the ten common heteroaromatic aldehydes, picolinaldehyde (32) had a high inhibitory effect on Chinese amaranth which closely related to the effect of (E)-crotonaldehyde (5) and (E)-cinnamaldehyde (7), whereas, other heteroaromatic aldehydes showed lower effects. In the case of a monocot plant, barnyardgrass, no tested aldehydes reduced seed germination, however, (E)-cinnamaldehyde (7), 2,4,6-trimethoxybenzaldehyde (16) and 4-(dimethylamino)benzaldehyde (24) could inhibit the seedling growth of the plant with low to moderate levels. The herbicidal effects of the most active aldehydes were then further investigated in order to find the minimum concentration of these aldehydes suppressing the germination and growth of the tested plants. At concentrations as low as 50–100 μM some aldehydes could inhibit the seedling growth of the tested species. The structure-activity relationship (SAR) study reported here demonstrates the chemical clues governing the inhibitory activity of aldehydes which could be utilized in the development of highly effective herbicides in the near future.

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“…Weeds that mature with the crop tend to be spread as contaminants in the harvested crop and in subsequently planted seed (Bayer, 1991). Seed contaminated with weed seeds may introduce new species to a given field or add to an existing weed population.…”

Section: Introductionmentioning

confidence: 99%

Weed seeds in rice seed shipments: A case study

Huelma¹,

Moody²,

Mew³

1996

International Journal of Pest Management

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Weed seeds in rice seed shipments: a case study (Abstract. The Seed Health Unit of the International Rice Research Institute (IRRI) conducts seed quarantine tests of incoming and outgoing rice seeds. Forty-eight percent of the incoming shipments did not carry the necessary phytosanitary certificate from the point of origin. Fifteen percent of the incoming rice seed shipments and 0.3% of the outgoing rice seed shipments were contaminated with weed seeds. Twenty weed species were identified as rice seed contaminants. Echinochloa spp. were the most frequent, with as many as 436 seeds per seed-lot. Storage fungi Penicillium spp., Aspergillus sp. and Rhizopus sp. were detected in incoming Echinochloa spp. weed seeds. Pathogenic seedborne fungi such as Bipolaris oryzae and Fusarium moniliforme were detected from IRRI field-collected Echinochloa spp. seeds. More care in processing rice seeds for germplasm exchange is needed to prevent weed seed contamination and spread.

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Weed Management

Cited by 4 publications

References 6 publications

Herbicidal Activity of Flavokawains and Related trans-Chalcones against Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

Herbicidal Activity of Flavokawains and Related trans-Chalcones against Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

Inhibitory Effects of a Variety of Aldehydes on Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.

Weed seeds in rice seed shipments: A case study

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