Efficacy ofExserohilum monocerasfor the control ofEchinochloaspecies in rice (Oryza sativa)

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 144-150 ◽  
Author(s):  
Wenming Zhang ◽  
Alan K. Watson

Efficacy of an indigenous fungus,Exserohilum monoceras, for the control of 3Echinochloaspecies was evaluated and compared under both regulated greenhouse and screenhouse (field plots netted with 2 layers of metal mesh screening to exclude vertebrate pests) conditions. Under greenhouse conditions, an inoculum dose of 2.5 × 107conidia m−2killed all seedlings of both barnyardgrass andE. glabrescens, whereas an inoculum dose of 5.0 × 107conidia m−2was required to obtain 100% mortality of junglerice seedlings. The 1.5-leaf stage of all 3Echinochloaspecies was the most susceptible. Increasing inoculum density increased weed control efficacy on younger or olderEchinochloaseedlings. The highest level of control was observed forE. glabrescens, less for barnyardgrass, and least for junglerice. Under screenhouse conditions,Exserohilum monocerascaused more than 90% mortality ofEchinochloaspecies when the inoculum was formulated as an oil emulsion or when applied as a dry powder.

2011 ◽  
Vol 9 (2) ◽  
pp. 597 ◽  
Author(s):  
J. Cavero ◽  
C. Zaragoza ◽  
A. Cirujeda ◽  
A. Anzalone ◽  
J. M. Faci ◽  
...  

1990 ◽  
Vol 4 (4) ◽  
pp. 838-842 ◽  
Author(s):  
James E. Hill ◽  
Stacey R. Roberts ◽  
D. E. Bayer ◽  
J. F. Williams

In five field experiments from 1986 to 1988, herbicides were evaluated alone and in combinations for weed control in water-seeded rice. Combinations of bensulfuron with either molinate or thiobencarb applied into the paddy water at the 2-leaf stage of rice, controlled all broadleaf and sedge weeds, and 92% or more early watergrass. These combinations were equivalent to a commercial standard of molinate at the 2-leaf stage followed by a separate application of bentazon to the drained paddy at midtillering.


2015 ◽  
Vol 29 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Garret B. Montgomery ◽  
Jason A. Bond ◽  
Bobby R. Golden ◽  
Jeffrey Gore ◽  
H. Matthew Edwards ◽  
...  

Research was conducted in Mississippi in 2012 and 2013 to compare the efficacy of saflufenacil to other broadleaf herbicides applied in mixtures with imazethapyr in a Clearfield rice system. Saflufenacil at 50 g ai ha−1, carfentrazone at 35 g ai ha−1, a prepackaged mixture of halosulfuron plus thifensulfuron at 35 plus 4 g ai ha−1, and a prepackaged mixture of propanil plus thiobencarb at 2,240 plus 2,240 g ai ha−1 were applied in mixture with imazethapyr at 70 g ai ha−1 early-POST (EPOST) to rice in the one- to two-leaf stage or late-POST (LPOST) to rice in the four-leaf to one-tiller stage. No differences in injury among the broadleaf herbicides or between application timings were detected at any evaluation. Imazethapyr combined with propanil plus thiobencarb or saflufenacil provided the greatest control of barnyardgrass 7 and 14 d after treatment (DAT). Hemp sesbania, ivyleaf morningglory, and Palmer amaranth control was greatest and similar for imazethapyr combined with carfentrazone, propanil plus thiobencarb, and saflufenacil; however, rough rice yield was greatest for imazethapyr combined with propanil plus thiobencarb or saflufenacil. Propanil plus thiobencarb or saflufenacil can be used in a Clearfield rice system to achieve optimum weed control and highest rice yields.


Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Gary Peng ◽  
K. N. Byer ◽  
K. L. Bailey

One hundred and thirty-three fungal isolates, pathogenic to green foxtail, were evaluated for weed control potential under controlled conditions. To determine weed control efficacy, these pathogens were applied as spore or mycelial suspensions at approximately 105propagules ml−1to green foxtail at the three-leaf stage. One week after inoculation, most isolates caused only minor injury to the plants, but 15 isolates caused 50 to 100% disease. Among the most efficacious isolates, only those ofPyricularia setariaeexhibited strong host specificity to the target weed, revealing no significant pathogenicity on 28 other plant species tested, including many important crops such as wheat, barley, and oat. On green foxtail leaves, conidia of this fungus germinated readily at 14, 20, and 26 C, but the process of germination and appressorial formation was more rapid at the higher temperatures. The fungus applied at the concentration of 105spores ml−1reduced weed fresh weight by 34% 7 d after the treatment when compared with controls, whereas a concentration of 107spores ml−1reduced fresh weight by 87%. This efficacy was comparable with that of the herbicide sethoxydim. When applied to the weed at the one- to four-leaf stages, the fungus reduced green foxtail fresh weight by more than 80%. Efficacy was slightly lower on plants at the five-leaf stage or older. On the green foxtail biotype resistant to the herbicide sethoxydim,P. setariaecaused 80% fresh weight reduction compared with untreated controls, as opposed to 17% achieved with the herbicide. At 20 C, the fungus required a minimum of 6-h dew period to initiate infection, but a 10-h dew period was needed to cause severe damage to green foxtail.


2021 ◽  
pp. 1-25
Author(s):  
Matthew J. R. Goddard ◽  
Clebson G. Gonçalves ◽  
Shawn D. Askew

Abstract Mesotrione typically requires multiple applications to control emerged weeds in turfgrass. Since it is absorbed by both foliage and roots, a controlled-release (CR) formulation could eliminate the need for multiple applications. Research was conducted evaluate simulated-release scenarios that mimic a potential CR mesotrione formulation. A soluble concentrate formulation of mesotrione was titrated to produce a stepwise change in mesotrione rates, which were applied daily to mimic predetermined release scenarios over a three-wk period. CR scenarios were compared to a broadcast treatment of mesotrione at 280 g ai ha-1 applied twice at three-wk intervals, and a nontreated. Mesotrione applied in three temporal release scenarios controlled creeping bentgrass, goosegrass, nimblewill, smooth crabgrass, and white clover equivalent to the standard sprayed mesotrione treatment in every comparison. However, each CR scenario injured tall fescue 2 to 7 times more than the standard treatment. Soil- and foliar-initiated repeat treatments were equivalent in most comparisons. Data indicates that mesotrione applied in a temporal range to simulate controlled release scenarios can deliver desired weed control efficacy comparable to sequential broadcast applications. More research is needed to elucidate proper timings and release scenarios to minimize turfgrass injury.


Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 608-618 ◽  
Author(s):  
Martina Keller ◽  
Geoffroy Gantoli ◽  
Jens Möhring ◽  
Christoph Gutjahr ◽  
Roland Gerhards ◽  
...  

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.


2013 ◽  
Vol 04 (04) ◽  
pp. 890-895 ◽  
Author(s):  
Sathya Priya Ramalingam ◽  
Chinnusamy Chinnagounder ◽  
Manickasundaram Perumal ◽  
Murali Arthanari Palanisamy

2018 ◽  
Vol 63 (2) ◽  
pp. 399-404
Author(s):  
Thi Hien LE ◽  
Wei Qiang JIA ◽  
Ok Jae WON ◽  
Taek–Keun OH ◽  
Yoshiyuki SHINOGI ◽  
...  

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 303-308 ◽  
Author(s):  
E. P. Richard ◽  
H. R. Hurst ◽  
R. D. Wauchope

Levels of MSMA (monosodium methanearsonate) that simulated drift (0.2, 0.39, and 0.78 kg/ha) were applied over-the-top to rice (Oryza sativaL. ‘Vista’, ‘Starbonnet’, or ‘Labelle’) after flooding at four developmental stages between early tillering and late jointing. The MSMA rates used were equivalent to, or lower than, the 0.78-kg/ha rate that would be applied as an over-the-top application to cotton (Gossypium hirsutumL.) for early season weed control. Over-the-top applications of MSMA did not affect heading and maturity dates of filled grains regardless of the rate or application timing. Reductions occurred, however, in plant height, number of panicles, and yield. In addition, the percentage of erect panicles showing typical “straighthead” symptoms increased. Rice sensitivity to MSMA depended on MSMA rate and stage of growth with injury being most severe as rice approached the reproductive stages of development. Because aerial applications of MSMA to cotton are normally made before rice reaches the reproductive stage, injury resulting from MSMA drift should be minimal.


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