Moss, S. R.

English

Rothamsted Repository

Patron:		Her	Majesty	The	Queen	 	 Rothamsted	Research	Harpenden,	Herts,	AL5	2JQ		Telephone:	+44	(0)1582	763133	Web:	http://www.rothamsted.ac.uk/			 			Rothamsted Research is a Company Limited by Guarantee Registered Office: as above.  Registered in England No. 2393175. Registered Charity No. 802038.  VAT No. 197 4201 51. Founded in 1843 by John Bennet Lawes.		Rothamsted Repository DownloadG - Articles in popular magazines and other technical publicationsMoss, S. R. 2016. Identification of wild-oats (Rothamsted technical publication, 2016). Rothamsted Research. doi:10.23637/rothamsted.8v194 The publisher's version can be accessed at:• https://dx.doi.org/10.23637/rothamsted.8v194The output can be accessed at: https://repository.rothamsted.ac.uk/item/8v194/identification-of-wild-oats-rothamsted-technical-publication-2016.© 2019, Please contact library@rothamsted.ac.uk for copyright queries.03/12/2019 17:18 repository.rothamsted.ac.uk library@rothamsted.ac.ukRESEARCHROTHAMSTED®Identification of wild-oatsDr Stephen MossIn the UK, there are two main species which occur as weeds of arable crops. Their relative fequencies, as reported in the Atlas of the British Flora (2002), are given as the (%) of the 2852 10 x 10 km grid squares surveyed in which the species was detected.Avena fatua – common or spring wild-oat Occurs throughout England; more scattered distribution in Scotland and Wales. (55%).Germinates mainly in spring (March/April) but with a variable, and sometimes considerable, amount of autumn germination too (mainly Sept/Oct).Avena sterilis ssp. ludoviciana – winter wild-oatLess common and mainly found within 50 – 100 miles of Oxford where it was first recorded in the wild in 1910. (10%). Probably under-reported due to confusion with Avena fatua. Germinates mainly in autumn and winter, from October to early March, and is more tolerant of freezing conditions than Avena fatua.Avena sterilis ssp. ludoviciana is generally considered the more challenging species to control, requiring more robust strategiesSeedling emergence patterns and winter hardiness differ between the two species so correct identification can help in herbicide decision-making Although herbicide resistance has been found in both species, it is relatively more common in Avena sterilis ssp. ludoviciana. The first cases of resistance in the UK were all found in this species despite its more limited distribution.Why does identification of species matter?Both species may occur within a single field, sometimes in mixture but sometimes in separate patches.At the vegetative stage, wild-oats can be identified in cereal crops by:It is not possible to identify reliably the different species of wild-oats at the vegetative stageNo auricles on wild-oats (or cultivated oats) but leaf margins often hairy.The lower half of leaves of wild-oats (and cultivated oats) tend to twist anti-clockwise when viewed from above (but note the leaf tips often twist clockwise)Wheat and barley leaves tend to twist clockwise when viewed from above.Hairy leaf margins and the absence of auriclesLeaves twisting the opposite wayWheat - well developed, hairy auricles (hairs restricted to the auricles).Barley - large, hairless auricles.AuriclesAvena fatua – seeds separate when mature and are shed singly.Avena sterilis ssp. ludoviciana – the two to three seeds within each spikelet remain attached together and are shed as a unit.AcknowledgementsThis leaflet was written by Stephen Moss Consulting for the CROPROTECT knowledge transfer initiative and designed by the Visual Communications Unit of Rothamsted Research, which is a national institute of biosciences strategically funded by BBSRC. The maps are reproduced with permission of the Botanical Society of Britain and Ireland (BSBI) and the Biological Records Centre (BRC). With thanks to Graham Shephard for photography.CROPROTECT is a knowledge exchange system to support UK growers in sustainable crop protection to allow efficient crop production. See http://croprotect.com (or search for ‘CROPROTECT‘) for more information.An electronic version of this leaflet is available on the CROPROTECT website and at: www.rothamsted.ac.uk/toolsInformation sourcesNew Atlas of the British and Irish Flora. (2002). By C D Preston, D A Pearman & T D Dines. Oxford University Press, Oxford, UK. 910 pp. (Online version:  https://www.brc.ac.uk/plantatlas/)Wild-oats in World Agriculture. (1976). Edited by D P Jones. Agricultural Research Council, London. 296 pp.The best time for this assessment in wheat crops is in late July or early August when most seed shedding occurs.This characteristic is most easily assessed by holding panicles inside a polythene bag and shaking vigorously.Samples collected in this manner will consist almost entirely of seeds, with no stalks, chaff or other debris.Unripe seeds of both species will tend to remain attached together, so this identification method is less suitable for use prior to seed shedding.The first and second seeds in the spikelets of both species are always awned.A fully developed 3rd seed is often not present – look at the biggest spikelets on the biggest plants to increase the chances of success.The presence or absence of awns can often be assessed on vestigial (not fully developed) seeds – see photo left. Easier with a hand lens.This identification method can be used any time after panicle emergence.After wild-oat panicles have emerged, two features make it easy to identify the two species.1. Presence or absence of an awn on the third seed in a spikelet2. Whether seeds remain attached to each other or separate at sheddingAwn present on 3rd seed in spikelet (and 4th seed if present)Awn absent on 3rd seed in spikelet(and 4th seed if present)Vestigial 4th seedAvena fatua Avena sterilis ssp. ludoviciana A Rothamsted technical publication, 2015. Rothamsted Research, Harpenden, Herts AL5 2JQ, UK Information in this document may be reproduced freely, provided the source is acknowledged.October 2015RESEARCHROTHAMSTED®

Identification of wild-oats (Rothamsted technical publication, 2016)

https://repository.rothamsted.ac.uk/download/691bab28929430df32d7dc79418c0cc1b4ba1586752143e707ca4992b1b9eded/4061756/Identification%2520of%2520wild-oats%2520%28Rothamsted%2520technical%2520publication%252C%25202016%29.pdf

Identification of wild-oats (Rothamsted technical publication, 2016)

Abstract

Similar works

Full text

Available Versions

Rothamsted Repository