scholarly journals Control of Seed Transmission of Cylindrocladium parasiticum in Peanut with Seed Treatment Fungicides

2003 ◽  
Vol 30 (2) ◽  
pp. 128-133
Author(s):  
D. L. Glenn ◽  
P. M. Phipps ◽  
R. J. Stipes

Abstract Seeds of peanut cultivars VA 98R and NC-V11 with speckled testae were treated with fungicide and assayed on a selective medium to determine the viability of Cylindrocladium parasiticum. The fungus was isolated from 78 and 90% of the untreated speckled seed of the respective cultivars. Seed treatment with captan + pcnb + carboxin, fludioxonil, captan, and thiophanate methyl significantly reduced recovery of the pathogen in both cultivars. Speckled seed of VA 98R and NC-V11 were treated with fungicides and planted in greenhouse and/or field trials in Suffolk, VA. Plants became infected with C. parasiticum after treated and untreated speckled seed were planted in steam-treated soil in the greenhouse. In one trial, seed treatment with fludioxonil, tebuconazole, and LS 176 significantly reduced taproot colonization by C. parasiticum compared to the untreated check. In a second greenhouse trial, only fludioxonil provided significant suppression of disease. In the field, treatment with fludioxonil, thiram, and tebuconazole significantly lowered Cylindrocladium black rot (CBR) incidence compared to the untreated check. Thiram significantly reduced taproot colonization compared to all treatments except fludioxonil. Based on the present study, the addition of thiram and/or fludioxonil to the standard treatment of captan + pcnb + carboxin may offer the best protection against seed transmission of C. parasiticum.

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 362-370 ◽  
Author(s):  
B. L. Randall-Schadel ◽  
J. E. Bailey ◽  
M. K. Beute

Seedborne Cylindrocladium parasiticum has been reported in peanuts and the possibility of seed transmission postulated; however, seed transmission has not been documented. Cinnamon brown speckles on peanut testae were correlated with isolation of C. parasiticum. Microscopy indicated that seed were colonized by cinnamon brown colored hyphae and microsclerotia interspersed in and on lightened areas of testa. Speckled seed from commercial seed lots (cultivars NC 7, NC 10C) were planted, with or without a chemical seed treatment (1992, captan + carboxin + dicloran [45:18:15% of product]; 1993 to 1995, captan + PCNB + carboxin [45:15:10% of product]), in fumigated fields with no history of peanut production. Asymptomatic seed from noninfested seed lots (cultivar NC-V 11 or NC 7) were checks for soilborne inoculum. C. parasiticum was isolated from all symptomatic seed lots prior to planting (percentage ranged from 4 to 45%) but was not isolated from asymptomatic seed. Seed transmission occurred from seed both with chemical seed treatment (0.25 to 2.75%) and without seed treatment (0.25 to 6.0%), but not in all years. Asymptomatic seed planted 2.5 cm from speckled seed increased the number of plants with Cylindrocladium black rot from two- to sixfold, illustrating the ability of disease to spread from colonized seed to uninfected plants. It was concluded that seed transmission of C. parasiticum is an important means by which this disease is spread within the seed industry.


2012 ◽  
Vol 39 (1) ◽  
pp. 38-42 ◽  
Author(s):  
W. D. Branch ◽  
T. B. Brenneman

Abstract Cylindrocladium Black Rot (CBR) caused by Cylindrocladium parasiticum Crous, Wingfield, & Alfenas syn. C. crotalariae (Loos) Bell & Sobers is a major disease problem in southeast U.S. peanut (Arachis hypogaea L.) production. Field trials were conducted for two-years (2008-09) at a test site (Gibbs Farm) that has a long history of continuous peanut production near the Univ. of Georgia, Coastal Plain Expt. Station, Tifton, GA to evaluate for CBR resistance among new runner-type peanut cultivars. All plots were artificially inoculated with microsclerotia of C. parasiticum after planting each year. Significant differences (P≤0.05) were found among the cultivars and advanced breeding lines for both CBR resistance and tomato spotted wilt virus (TSWV) resistance which was also present each year, but the predominant disease was CBR. Georgia Greener, Georgia-06G, Georgia-07W, Georgia-02C, and Carver were consistently found to be the most CBR resistant; whereas, C-99R and Tifguard were the most susceptible each year. In separate CBR tests conducted in 2009 and 2010 at a different location (Blackshank Farm), Georgia Greener also had the least difference, and Tifguard had the greatest difference, between C. parasiticum inoculated versus non-inoculated plots for pod yield. These combined test results demonstrate that useful levels of CBR resistance are currently available in promising new runner-type peanut cultivars.


Plant Disease ◽  
2016 ◽  
Vol 100 (7) ◽  
pp. 1364-1370 ◽  
Author(s):  
Carl A. Strausbaugh ◽  
Erik J. Wenninger ◽  
Imad A. Eujayl

Curly top in sugar beet caused by Beet curly top virus (BCTV) is an important yield-limiting disease that can be reduced via neonicotinoid and pyrethroid insecticides. The length of efficacy of these insecticides is poorly understood; therefore, field experiments were conducted with the seed treatment Poncho Beta (clothianidin at 60 g a.i. + beta-cyfluthrin at 8 g a.i. per 100,000 seed) and foliar treatment Asana (esfenvalerate at 55.48 g a.i./ha). A series of four experiments at different locations in the same field were conducted in 2014 and repeated in a neighboring field in 2015, with four treatments (untreated check, Poncho Beta, Asana, and Poncho Beta + Asana) which were arranged in a randomized complete block design with eight replications. To evaluate efficacy, viruliferous (contain BCTV strains) beet leafhoppers were released 8, 9, 10, or 11weeks after planting for each experiment, which corresponded to 1, 2, 3, and 4 weeks after Asana application. Over both years, in 30 of 32 observation dates for treatments with Poncho Beta and 14 of 16 observation dates for Asana, visual curly top ratings decreased an average of 41 and 24%, respectively, with insecticide treatments compared with the untreated check. Over both years, in eight of eight experiments for treatments with Poncho Beta and six of eight experiments for Asana, root yields increased an average of 39 and 32%, respectively, with treatment compared with the untreated check. Over both years, the Poncho Beta treatments increased estimated recoverable sucrose (ERS) yield by 75% compared with the untreated check for weeks 8 and 9. By week 10, only the Poncho Beta + Asana treatment led to increases in ERS in both years, while the influence of increasing host resistance may have made other treatments more difficult to separate. When considering curly top symptoms, root yield, and ERS among all weeks and years, there was a tendency for the insecticides in the Poncho Beta + Asana treatment to complement each other to improve efficacy.


2021 ◽  
Vol 12 (5) ◽  
pp. 286-294
Author(s):  
Poornata Jena ◽  
◽  
N. K. Sahoo ◽  
J. K. Mahalik ◽  
◽  
...  

A pot experiment was carried out in the net house of Department of Nematology, OUAT, Bhubaneswar, Odisha, India during June to August, 2017 on the application of oilcakes (mustard cake and neem cake) and bio-agents (Trichoderma viride, Glomus fasciculatum, Rhizobium leguminosarum) each alone and in combination for the management of root knot nematode (Meloidogyne incognita) in green gram. Result of the experiment indicated that soil application of mustard or neem cake @ 50 g m-2 with AM fungus (Glomus fasciculatum) @ 5 g m-² and seed treatment of Rhizobium @ 25 g kg-1 of green gram seed declined the root knot nematode population, number of galls plant-1, number of eggmass plant-1and root knot index with corresponding increase of plant growth parameters and chlorophyll content in green gram plant as compared to other treatments and untreated check. But integration of mustard cake @ 50 g m-2 at 2 weeks prior to sowing with AM fungus @ 5 g m-2 at 10 days before sowing and seed treatment of Rhizobium @ 25 g kg-1 green gram seed exhibited the lowest M. incognita population 200 cc soil-1 (153.33 J2), number of galls plant-1 (7.0), number of eggmass plant-1 (2.0) and root knot index (2.0) reflecting enhancement of plant growth parameters, number of pods (206.67%), number of nodules (691.17%) over untreated check. This integrated management module also recorded maximum increase in the availability of NPK content in soil and chlorophyll content as compared to other treatments.


Author(s):  
P. Holliday

Abstract A description is provided for Septoria helianthi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Helianthus annuus, Helianthus grosseserratus and Helianthus rigidus. DISEASE: Leaf spot of sunflower. Yellowish spots up to 1.5 cm develop over the whole lamina, gradually turning necrotic and becoming almost black. The numerous pycnidia are mostly on the adaxial surface. The lesions have a polygonal outline, being sharply delimited by the veins. Infection may begin on the cotyledons and young leaves, spreading to later developing leaves. Severe attacks lead to defoliation and loss in yield. GEOGRAPHICAL DISTRIBUTION: Fairly widespread in E. Europe and the U.S.S.R. in Asia, China, Japan, Australia (Qd.); E. and S. Africa, N. America (CMI Map 468, ed. 1, 1970). TRANSMISSION: Overwintering occurs in host debris. Seed treatment is recommended although seed transmission does not appear to have been demonstrated. Introduction of the fungus into Hungary may have been via seed (43, 2013).


1998 ◽  
Vol 23 (1) ◽  
pp. 249-249
Author(s):  
D. E. Bragg ◽  
J. W. Burns

Abstract Plots were established 12 May near Albion, WA, on the Mills-Farr farm in a RCBD with 4 replicates of 6 X 10 ft. each. Seven insecticide treatments and an untreated check were used, with Gaucho 480 applied as a seed treatment at 0.5 and 1.0 oz (AI)/cwt. Foliar treatments were applied at the appearance of PA ca. 40-DAE using a CO2-powered backpack sprayer at 20 gpa at 20 psi. All treatments were rated by counts of PA per 20 cm terminal stem 4 per replicate at pre-treatment, PrCt, 2, 5, 7, 10, and 15 DAT. Counts of (TPB) damaged lentils/100 lentil sample per replicate were made at harvest. Yield data in oz lentils per replicate were collected by threshing through a stationary thresher.


Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2212-2220
Author(s):  
Jhonatan P. Barro ◽  
Maurício C. Meyer ◽  
Claúdia V. Godoy ◽  
Alfredo R. Dias ◽  
Carlos M. Utiamada ◽  
...  

White mold, caused by Sclerotinia sclerotiorum, is a yield-limiting disease of soybean in Brazil. Uniform fungicide trials have been conducted annually since 2009. Data from 74 cooperative field trials conducted over a 10-year period were assembled. We selected five fungicides applied two times around flowering: dimoxystrobin plus boscalid (DIMO+BOSC), carbendazim plus procymidone (CARB+PROC), fluazinam (FLUZ), fluopyram (FLUO), and procymidone (PROC). For comparison, thiophanate-methyl (TMET) applied four times was also included as a low-cost treatment. Network models were fitted to the log of white mold incidence (percentages) and log of sclerotia mass data (grams/hectare) and to the nontransformed yield data (kilograms/hectare) for each treatment, including the untreated check. Back-transformation of the meta-analytic estimates indicated that the lowest and highest mean (95% confidence interval [CI]) percent reductions in incidence and sclerotia mass were 54.2 (49.3 to 58.7) and 51.6% (43.7 to 58.3) for TMET and 83.8 (79.1 to 87.5) and 87% (81.9 to 91.6) for CARB+PROC, respectively. The overall mean (95% CI) yield responses ranged from 323 kg/ha (247.4 to 400.3) for TMET to 626 kg/ha (521.7 to 731.7) for DIMO+BOSC, but the variance was significantly reduced by a binary variable (30% threshold) describing disease incidence in the untreated check. On average, an increment of 352 kg/ha was estimated for trials where the incidence was >30% compared with the low-disease scenario. Hence, the probability of breaking even on fungicide costs for the high-disease scenario was >65% for the more effective, but more expensive fungicide (FLUZ) than TMET. For the low-disease scenario, profitability was less likely and depended more on variations in fungicide cost and soybean price.


1989 ◽  
Vol 29 (5) ◽  
pp. 641 ◽  
Author(s):  
J Evans ◽  
GE O'Connor ◽  
G Griffith ◽  
J Howieson

Lupin nodulation is reduced when seed of this legume is treated with commercial inoculant (Rhizobium lupini WU425) and the fungicide Rovral (a.i. iprodione). The number of WU425 colonising soil beneath lupin seedlings established without iprodione was greater than where iprodione was used. R. lupini CC606B has greater tolerance of iprodione than WU425; 85% of CC606B survived 15 min in iprodione (Rovral 16 g/L), compared with <1% survival of WU425. CC606B fixed as much nitrogen as WU425 on serradella grown in sand culture, but it nodulated lupin poorly in the field. It was shown that CC606B comprised bacteria that were either positive or negative for nodulation of serradella and lupin. Thus, an isolate of CC606B (CC606B/1), able to form nodules on lupin and serradella and also tolerant of iprodione (Rovral 16 g/L), was selected and compared with WU425 as inoculants of lupin, in field trials with and without iprodione seed treatment. In the treatments without the fungicide, CC606B/1, like its parent, failed to nodulate lupin as extensively as WU425. CC606B/1 was unable to colonise soil beneath lupin crops as well as WU425. With iprodione, nodulation by CC606B/1 was significantly worse than without the fungicide; so the tolerance level of CC606B/1 to iprodione was insufficient. With these treatments it was shown that nodule abundance in late winter was related to the abundance of rhizobia in the soil beneath lupin seedlings in early winter. When there were fewer nodules, less dry matter was produced; but grain yield was not affected by the reductions in nodulation and dry matter. The implications of these changes on N2 fixation and lupin effects on soil N are discussed. Other species and strains of Rhizobium varied in their ability to survive iprodione.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1469
Author(s):  
Silke Deketelaere ◽  
Katrijn Spiessens ◽  
Sabien Pollet ◽  
Lien Tyvaert ◽  
Luc De Rooster ◽  
...  

Verticillium wilt is one of the most important diseases of cauliflower and can lead to serious economic losses. In this study, two complementary strategies were explored to employ the antagonistic capacity of Verticillium isaacii towards Verticillium wilt of cauliflower. The first strategy focused on introducing V. isaacii Vt305 by artificial inoculation of cauliflower plantlets at the nursery stage. Two inoculum types (spores and microsclerotia of V. isaacii Vt305) and different concentrations of microsclerotia were tested in greenhouse and field trials. Seed treatment with 500 microsclerotia seed−1 led to a satisfying biocontrol level of Verticillium wilt. In addition, the PHYTO-DRIP® system was successful in delivering the microsclerotia to cauliflower seeds. The second strategy relied on the stimulation of the natural V. isaacii populations by rotating cauliflower with green manures and potato. Four green manure crops and potato were tested during multiple field experiments. Although these crops seemed to stimulate the V. isaacii soil population, this increase did not result in a control effect on Verticillium wilt of cauliflower in the short term. Importantly, our results indicate that the use of green manures is compatible with the application of V. isaacii Vt305 as biocontrol agent of Verticillium wilt in cauliflower.


2002 ◽  
Vol 37 (4) ◽  
pp. 308-316 ◽  
Author(s):  
J. C. Faircloth ◽  
J. R. Bradley ◽  
J. W. Van Duyn

Field experiments were conducted in 1997–1999 in Washington Co., NC, to examine how cotton, Gossypium hirsutum, is affected by thrips species composition and abundance, environmental factors, and insecticide applications. Populations of adult and juvenile thrips were monitored in seedling cotton treated with insecticide applications of either imidacloprid as a seed treatment, acephate as a foliar spray, or aldicarb applied in-furrow. The number of plants per 3.05 row-m, location of the first fruiting branch, number of open bolls per 1.52 row-m, yields, accumulated degree-d 60′s (DD60′s), and accumulated rainfall were recorded each year the studies were conducted. Aldicarb and acephate provided better thrips control than did imidacloprid in all 3 yrs. Thrips species ratios differed among years. In 1997, the aldicarb treatment resulted in a better “earliness profile” (lower fruit set and more early opening bolls) than either acephate or imidacloprid, while in 1998 and 1999 there were few differences in these plant parameters. In 1997, all insecticide treatments resulted in statistically higher yields compared with the untreated check. Accumulated DD60′s were consistently higher in 1998 and 1999 than in 1997 after the first thrips sampling date. Cumulative rainfall appeared to be inversely associated with juvenile thrips populations.


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