Vol. 54—2000 - NorthEastern Weed Science Society
Share Embed Flag
Download ePaper

Vol. 54—2000 - NorthEastern Weed Science Society

Vol. 54—2000 - NorthEastern Weed Science Society Vol. 54—2000 - NorthEastern Weed Science Society

newss.org
08.06.2015 Views

LONGEVITY OF PREEMERGENCE CRABGRASS HERBICIDES Jeffrey F. Derr' ABSTRACT Studies were conducted to determine the length of residual control for commonly-used turf preemergence herbicides. In the first study, flats were buried in a field location aod filled with native soil. The pH was 5.3 with 1.5% organic matter. Six flats were used per plot. Herbicides applied as sprays aod their application rates were: prodiamine, 0.75 Ib ai/A; pendirnethalin, 3.0 IblA; dithiopyr, 0.5 IbfA; bensulide, 10.0 IbfA; siduron, 10.0 IblA; aod oryzaIin, 3.0 IbiA. The following herbicides were applied in granular form at 3.0 IbfA: benefin, benefin plus trifluralin aod oxadiazon. Plots were treated on April 3, 1998. A rain totaling 1.75" fell 1 day after treatment. Flats were removed at 0, I, 2, 3, 4, aod 5 months after treatment (MAn aod seeded with large crabgrass [Digitaria sangutnolis (L.) Scop.] aod yellow foxtail [Setaria glauca (L.) Beauv.]. Flats were maintained in the greenhouse. Shoot fresh weight was recordedapproximately1monthafterseeding. At 0 MAT, all treatments controlled both weed species greaterthao 95%. At 1 MAT, all chemicalsexceptbenefinplustrifluralinreducedlargecrabgrassshootweight by over 95%. All treatmentsexcept bensulide, benefin, and benefinplus trifluralinreducedyellow foxtail shoot weight by over 90%. At 2 MAT, only prodiamine,pendimethalin,andoxadiazonreducedshoot weight of both species by over90%. By 3 MAT, only prodiamineprovidedover 90%reduction in large crabgrass shoot weight, while oxadiazon reduced shoot weight by 89%. At 3 MAT, numerical reduction in large crabgrass shoot weight was in the order, from greatest to least: prodiarnine, oxadiezon, oryzalin, pendirnethaIin, bensulide, dithiopyr, siduron, benefin, aod benefin plus trifluraIin. Only prodiarnine aod oxadiazon reduced yellow foxtail shoot weight over 90% at 3 MAT. BY 4 MAT, no treatmentreduced large crabgrass shoot weight by 90% or more. Prodiamine reduced large crabgrass shoot weight by approximately 80% while all other treatments gave less than a 50% reduction. Oxadiazon reduced yellow foxtail shoot weight by approximately 85% at 4 MAT. All other treatments provided less than70% reduction. At 5 MAT, all treated flats had a similar large crabgrass shoot weight as the untreated flats. At 5 MAT, prodiamine aod oxadiazon reduced yellow foxtail shoot fresh weight by approximately 55 and 75%, respectively. Shoot weights in the other treatments were similar to that in untreated flats. A second study was conducted in an established turf site. At 3 MAT, prodiamine, pendimethalin, dithiopyr, bensulide, benefin plus trifluralin, oxadiazon, andbenefin all provided over 800/0control of a mixtureof large and smooth crabgrass. At 5 MAT, prodiarnine, benefln plus trifluralin, and oxadiazon controlled large and smooth crabgrass 70% or greater. Pendimethalin, dithiopyr, bensulide, and benefin controlled large and smooth crabgrass less than 60% at 5 MAT. Herbicide longevity is dependent upon the herbicide usedand weed species. 'Professor, 23455. Virginia Tech, Hampton Roads Ag. Res. and Ext. Center, Virginia Beach, VA 120

EFFICACY OF DITHIOPYR FORMULATIONS FOR PREEMERGENCE ANNUAL GRASS CONTROL R. B. Taylorson I ABSTRACT The study wasconducted during 1999 at the University of Rhode Island turf research farm on a 7-year old stand of Kentucky bluegrass (poa pratensis) aodcreeping redfescue(Festucarubra)mowedat 1.75inches. Theformulationsof dithiopyrwere applied to plots six feet wide by eightfeet long with a two foot untreated strip between adjacent plots. There were four replicates in a randomozed complete block design. Al1 treatments were applied on April21,1999 with either a backpack sprayer at 48 GPA or a Gaodydrop spreader. Ratings of smooth crabgrass

EFFICACY OF DITHIOPYR FORMULATIONS FOR<br />

PREEMERGENCE ANNUAL GRASS CONTROL<br />

R. B. Taylorson I<br />

ABSTRACT<br />

The study wasconducted during 1999 at the University of Rhode Island turf<br />

research farm on a 7-year old stand of Kentucky bluegrass (poa pratensis) aodcreeping<br />

redfescue(Festucarubra)mowedat 1.75inches. Theformulationsof dithiopyrwere<br />

applied to plots six feet wide by eightfeet long with a two foot untreated strip between<br />

adjacent plots. There were four replicates in a randomozed complete block design. Al1<br />

treatments were applied on April21,1999 with either a backpack sprayer at 48 GPA or<br />

a Gaodydrop spreader. Ratings of smooth crabgrass

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!