scholarly journals Sixty-One Years Following Registration, Phorate Applied In-Furrow at Planting Suppresses Development of Late Leaf Spot on Peanut

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2885-2890
Author(s):  
Daniel J. Anco ◽  
James S. Thomas ◽  
David L. Wright ◽  
Nicholas S. Dufault ◽  
Ian M. Small

Late and early leaf spot are caused by Nothopassalora personata and Passalora arachidicola, respectively, and are damaging diseases of peanut (Arachis hypogaea L.) capable of defoliation and yield loss. Management of these diseases is most effective through the integration of tactics that reduce starting inoculum and prevent infection. The insecticide phorate was first registered in 1959 and has been used in peanut production for decades in-furrow at planting to suppress thrips. Phorate further provides significant suppression of Tomato spotted wilt virus infection beyond suppression of its thrips vector alone by activating defense-related responses in the peanut plant. From six experiments conducted from 2017 to 2019 in Blackville, SC, Reddick, FL, and Quincy, FL, significantly less leaf spot defoliation was exhibited on peanuts treated with phorate in-furrow at planting (26%) compared with nontreated checks (48%). In-season fungicides were excluded from five of the experiments, whereas the 2018 Quincy, FL, experiment included eight applications on a 15-day interval. Across individual experiments, significant suppression of defoliation caused by late leaf spot was observed from 64 to 147 days after planting. Although more variable within location-years, pod yield following phorate treatment was overall significantly greater than for nontreated peanut (2,330 compared with 2,030 kg/ha; P = 0.0794). The consistent defoliation suppression potential was estimated to confer an average potential net economic yield savings of $90 to $120 per hectare under analogous leaf spot defoliation. To our knowledge, these are the first data in the 61 years since its registration demonstrating significant suppression of leaf spot on peanut following application of phorate in-furrow at planting. Results support phorate use in peanut as an effective and economical tactic to incorporate to manage late and early leaf spot infections and development of fungicide resistance.

2003 ◽  
Vol 30 (2) ◽  
pp. 108-111 ◽  
Author(s):  
W. D. Branch ◽  
J. A. Baldwin ◽  
A. K. Culbreath

Abstract Tomato spotted wilt virus (TSWV) resistant, runner-type peanut (Arachis hypogaea L.) cultivars are the most important defense to control spotted wilt disease in southeast U.S. peanut production. The objective of this 3-yr (1999–01) study was to evaluate six TSWV-resistant, runner-type cultivars (Southern Runner, Florida MDR 98, C-99R, ViruGard, Georgia Green, and Georgia-OIR) at three different seeding rates (3, 5, and 7 seed/30.5 cm) in single conventional row patterns for possible genotype (GE) × seeding rate (SR) interaction at the Univ. of Georgia, Coastal Plain Experiment Station. The combined split-plot analyses of variance resulted in highly significant (P ≤ 0.01) GE × SR interaction, which indicates that not all six runner-type cultivars performed the same at each of these three seeding rates. A good example was the TSWV-resistant, runner-type peanut cultivar Georgia Green. It performed subpar at the below normal or lowest seeding rate; whereas at the highest seeding rate, Georgia Green and Georgia-OIR produced the highest pod yields and dollar value returns per hectare among all of these runner-type cultivars. TSWV disease incidence was also significantly lower for the TSWV-resistant Georgia Green cultivar at each of the two higher seeding rates compared to the lowest seeding rate.


2008 ◽  
Vol 35 (2) ◽  
pp. 92-100 ◽  
Author(s):  
S. D. Riniker ◽  
R. L. Brandenburg ◽  
G. G. Kennedy ◽  
T. G. Isleib ◽  
D. L. Jordan

Abstract Tomato spotted wilt virus (TSWV), a thrips-vectored tospovirus, is an important pathogen of peanut (Arachis hypogaea L.). Development of tolerant cultivars has proven to be one of the most promising methods to manage the disease. Twenty-four genotypes of virginia market-type peanut were monitored in field tests for thrips damage, and TSWV incidence and severity during 2004 and 2005 in North Carolina. The cultivar Gregory had a higher density of adult thrips in foliage than any other genotype, while breeding lines N01057 and N03054E had the lowest density. No significant correlation was detected between thrips density or injury and TSWV incidence. Line N03036EJ had the greatest TSWV incidence, but did not differ from cultivars Gregory or Perry in incidence. Line N00033 had the least TSWV incidence and differed from the cultivars Gregory and Perry. The occurrence of late-season chlorosis or peanut yellowing death (PYD) was highly correlated with TSWV infection (P < 0.0001). Breeding line N02051ol had the greatest incidence of PYD, but did not differ statistically from Gregory or Perry. Lines N03023EF and N01083 had the least PYD incidence. Plants infected with TSWV not expressing foliar symptoms were found in far greater abundance than plants that were infected and symptomatic. Line N03036EJ had the greatest proportion of infected but asymptomatic plants; line N03054E had the least. Susceptible lines are more likely to become infected, rather than just more likely to show spotted wilt symptoms.


2002 ◽  
Vol 29 (2) ◽  
pp. 79-84 ◽  
Author(s):  
J. H. Lyerly ◽  
H. T. Stalker ◽  
J. W. Moyer ◽  
K. Hoffman

Abstract Tomato spotted wilt virus (TSWV) is an important plant pathogen with a wide host range, including the domesticated peanut (Arachis hypogaea L.). After initial outbreaks on peanut during the 1980s, the virus has spread to all peanut-producing states in the U.S. TSWV is transmitted by several species of thrips which are difficult to control with insecticides; therefore, control of TSWV most likely will come from selecting resistant genotypes in breeding programs. Although moderate levels of resistance have been discovered in A. hypogaea, complete virus resistance has not been found. Several Arachis species have desirable genes for plant resistances and tolerate many disease and insect pests better than the cultivated species. The objectives of this study were to (a) evaluate TSWV disease incidence and severity in accessions of Arachis species, and (b) compare levels of TSWV resistance in diploid species to selected A. hypogaea genotypes. In this study, 46 diploid Arachis spp. accessions were evaluated in the greenhouse by artificial inoculation tests for resistance to TSWV. Nine Arachis accessions were observed with no disease symptoms when TSWV isolate 10 was used as opposed to A. hypogaea lines that ranged from moderately to highly susceptible. Additional testing with more virulent isolates identified A. diogoi accession GKP 10602 and A. correntina accession GKP 9530 as highly resistant to the virus. These two accessions are being used as parents in crossing programs to incorporate TSWV resistance genes into A. hypogaea.


2004 ◽  
Vol 31 (2) ◽  
pp. 65-70 ◽  
Author(s):  
W. F. Anderson ◽  
G. Kochert ◽  
C. C. Holbrook ◽  
H. T. Stalker

Abstract Peanut breeders are constantly in search of new sources of genes that confer tolerance or resistance to biotic and abiotic stresses to improve the production and quality. The objective of this study was to evaluate peanut lines generated from interspecific crosses for amounts of wild species introgression, including genes for resistance to peanut root-knot nematodes, tomato spotted wilt virus and leaf spot diseases. Nine diploid Arachis species were crossed with peanut breeding lines and 130 different interspecific hybrid lines were developed. These lines were evaluated for the amount of introgression using RFLP analyses, plant morphology, and disease resistant phenotypes. Based on RFLPs, 41 lines showed measurable introgression and 12 hexaploid-derived lines were polymorphic for at least four probes. Greenhouse and field evaluations indicated that resistance was not present in the lines tested for tomato spotted wilt virus, early leaf spot, or Cylindrocladium black rot. However, resistance approaching that of the wild species was found for the peanut root-knot nematode (Meloidogyne arenaria) among lines derived from crosses with Arachis diogoi, A. correntina, A. batizocoi, and A. cardenasii. Introgression lines were resistant (disease ratings of 1.5 to 4.5 and lesion numbers 8 to 63) compared to Southern Runner (ratings of 5.5 to 6 and lesion numbers of nearly 500) for late leaf spot (Cercosporidium personation) in field evaluations performed in Gainesville, FL over 2 yr. The greatest resistance was found among lines from crosses with A. batizocoi, A. duranensis, A. stenosperma, A. magma, and A. diogoi. Results indicate that it should be possible to identify molecular markers to tag resistance genes for use in conventional breeding programs and stack these genes in highly productive peanut cultivars.


Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1237-1240 ◽  
Author(s):  
S. de Breuil ◽  
M. S. Nievas ◽  
F. J. Giolitti ◽  
L. M. Giorda ◽  
S. L. Lenardon

This is the first survey to determine the occurrence, prevalence, and distribution of peanut (Arachis hypogaea) viral diseases in Argentina. It was conducted in the province of Córdoba, which has 92% of the country's peanut production. It included the main peanut viruses Peanut mottle virus (PeMoV), Peanut stripe virus (PStV), Cucumber mosaic virus (CMV), Peanut stunt virus (PSV), Tomato spotted wilt virus (TSWV), and Groundnut ringspot virus (GRSV). Leaf samples from 1,028 individual peanut plants with virus-like symptoms and 986 samples from asymptomatic plants were collected in six counties of Córdoba over 3 years and serologically tested for the presence of viruses. PeMoV was the most frequently detected virus, found in 58.8, 34.2, and 23.4% of samples from the 2003–04, 2004–05, and 2005–06 growing seasons, respectively, and it was found in all sampled counties. Also, it was the only virus detected in asymptomatic plants. Less than 4% of symptomatic plants were infected with CMV or GRSV; 0.5, 3.6, and 2% of samples were positive for CMV; and 0.5, 3.1, and 1.6% were positive for GRSV in the 2003–04, 2004–05 and 2005–06 seasons, respectively. Some mixed infections were found: CMV-PeMoV and GRSV-PeMoV. During this survey, PSV, PStV, and TSWV were not detected in any peanut samples.


1961 ◽  
Vol 12 (2) ◽  
pp. 239 ◽  
Author(s):  
K Helms ◽  
NE Grylls ◽  
GS Purss

A disease of peanut (Arachis hypogaea L.) in Queensland, previously referred to as "chlorosis", was identified as being caused by the tomato spotted wilt virus. Symptoms of the disease on peanut are described. Erigeron bonariensis L., Tagetes minuta L., and Trifolium subterraneurn L. are recorded as new hosts. The disease was not seed-transmitted, although seeds developed lesions and were malformed. Infective virus was found in tissues of the integuments of immature seed. The maximum disease incidence recorded in an individual crop was 5.5%. The mean seed yield of diseased plants was 12.7 g per plant, whereas that of healthy plants was 128.2 g.


Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1161-1161 ◽  
Author(s):  
E. Marys ◽  
A. Mejías ◽  
E. Rodríguez-Román ◽  
D. Avilán ◽  
T. Hurtado ◽  
...  

Gerbera (Gerbera jamesonii) and Chrysanthemum (family Asteraceae) are two of the top 10 cut flowers of the world, with great commercial value. Since 1998, Venezuela began a floral industry to produce and export fresh cut gerbera and chrysanthemum, with 40% of nurseries concentrated in Altos Mirandinos (Miranda State, north central region of the country). For the past 2 years, greenhouse-grown gerbera and chrysanthemum have been observed displaying symptoms resembling those associated with tospoviruses. Symptomatic plants showed concentric rings, irregular chlorotic blotches, and deformation on leaves. Disease incidence was estimated at 30%. Mechanical inoculation with extracts of symptomatic leaves reproduced the typical concentric ring symptoms on indicator plants Arachis hypogaea L. cv. San Martín, Capsicum chinense, and G. jamesonii 6 to 15 days after inoculation. In initial tests, leaves from each 30 symptomatic gerbera and chrysanthemum species from several greenhouse facilities in Altos Mirandinos reacted positively when tested by DAS-ELISA with polyclonal antisera (ATCC, Rockville, MD) raised against Tomato spotted wilt virus (TSWV). Total RNA was extracted with the RNeasy Plant Mini kit (QIAGEN, Hilden, Germany) from two gerbera and two chrysanthemum ELISA-positive samples. The TSWV coat protein gene was amplified by conventional reverse transcription (RT)-PCR using primers CP1 TSWV (TTAACTTACAGCTGCTTT) and CP2 TSWV (CAAAGCATATAAGAACTT) (1). A single DNA product of ~823 bp was amplified from all samples. RT-PCR products were directly sequenced in both orientations and sequences were deposited in GenBank (Accession Nos. KF146700 and KF146701 derived from chrysanthemum, KF146702 and KF146703 derived from gerbera). The resulting sequences showed over 99% identity with each other. and were found to be closely related (over 99%) with TSWV isolates deposited in GenBank originating from different hosts from France (FR693058, FR693055), Montenegro (GU339506, GU339508, GU355940), Italy (HQ830187), New Zealand (KC494501), South Korea (KC261967), and the United States (AY744476). To our knowledge, this is the first confirmed report of TSWV infecting gerbera and chrysanthemum in Venezuela. The relatively widespread occurrence of TSWV in Miranda State underscores the need for systematic surveys to assess its incidence and impact on ornamental crops so that appropriate management tactics can be developed. Reference: (1) R. A. Mumford et al. J. Virol. Methods 57:109, 1996.


1995 ◽  
Vol 22 (1) ◽  
pp. 76-80 ◽  
Author(s):  
John S. Richburg ◽  
John W. Wilcut ◽  
Albert K. Culbreath ◽  
Craig K. Kvien

Abstract Field experiments conducted in 1992 and 1993 in Georgia evaluated the response of the peanut cultivars Florunner, Georgia Runner, Goldkist GK 7, NC 7, NC-V11, Southern Runner, Sunrunner, and AgraTech VC-1 to AC 263,222 applied early-postemergence (EPOST) at 71 g ha-1. Visual injury, which was less than 13%, was independent of cultivar, and injury was not evident on any cultivar midseason. AC 263,222 slightly reduced canopy width consistently on all cultivars. The only significant effect on percentage fancy pods, medium, No. 1, sound splits, damaged, and other kernels was the main effect of cultivar. There was a significant cultivar, AC 263,222, and cultivar-by-AC 263,222 effect on extra large kernels (ELK) and jumbo kernel percentages. Southern Runner and NC-V11 had significantly lower percentage jumbo and ELK, respectively when treated with AC 263,222. In addition, Florunner and Sunrunner also had numerically less percentage jumbo kernels. Reductions in percentages of ELK and jumbo were probably the result of AC 263,222-induced maturity delays. However, these reductions were not reflected in peanut yields. The occurence of late and early leaf spot, tomato spotted wilt virus (TSWV), and southern stem rot was independent of both cultivar and AC 263,222.


1995 ◽  
Vol 22 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Kenya K. Kresta ◽  
Forrest L. Mitchell ◽  
J. W. Smith

Abstract The foliage of individual field-infected peanut plants (Arachis hypogaea L.) was examined by enzyme-linked immunosorbent assay (ELISA) for the presence of tomato spotted wilt virus (TSWV). TSWV was detected commonly in terminals (folded quadrifoliates) and flowers, the vector's feeding and breeding niches. Reconstructions of the assayed plants demonstrated that the virus concentration varied from plant to plant and symptoms were significantly correlated to virus concentration in individual leaves and terminals. The virus was not distributed uniformly throughout individual plants but was concentrated in young, developing terminal tissue. The presence of symptoms was indicative of detectable virus 95% of the time.


2010 ◽  
Vol 37 (1) ◽  
pp. 39-43 ◽  
Author(s):  
R. S. Tubbs ◽  
E. P. Prostko ◽  
R. C. Kemerait ◽  
T. B. Brenneman ◽  
D. Q. Wann

Abstract Paraquat is a common herbicide used in peanut production; however, visible injury and reduced yield have been observed in some instances. Most research regarding paraquat injury on peanut has taken place on cultivars that are no longer available and were more susceptible to tomato spotted wilt virus (TSWV) than current cultivars. Field experiments were conducted over three growing seasons to determine the effect of paraquat on yield and TSWV incidence in two moderately TSWV-resistant cultivars (Georgia-02C and Georgia-03L). Paraquat and paraquat plus bentazon were evaluated against a non-treated control at four application timings [7, 14, 21, and 28 d after ground cracking (DAGC)]. There were no yield differences among herbicide treatments or application timings for Georgia-02C peanut, but there was a treatment interaction with Georgia-03L for yield. The majority of interaction comparisons showed no yield differences, but the non-treated control had higher yields than the herbicide treatments when significance did occur. Yields were similar for the 7 DAGC timing in all comparisons. In all instances when differences occurred for both cultivars, TSWV was higher in non-treated plots than where herbicides were applied. This data supports the use of paraquat in Georgia-02C and Georgia-03L peanut since there is minimal chance of yield reduction and may also reduce TSWV incidence; however, additional studies are required.


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