Influence of soil fumigation and seed tuber treatment on the control of Rhizoctonia solani on potatoes

1996 ◽  
Vol 36 (3) ◽  
pp. 339 ◽  
Author(s):  
TJ Wicks ◽  
B Morgan ◽  
B Hall

Five field experiments were conducted in South Australia to determine the effect of soil fumigation (metham sodium) and chemical and biological seed tuber dressing on the severity of Rhizoctonia solani on potato stems and tubers. These experiments indicated that both soil- and tuber-borne inoculum must be considered in any program aimed at controlling R. solani. Tuber treatments of either a 20 min dip in 2% formaldehyde, sprays with pencycuron (0.15 mL a.i./10 kg seed), iprodione (2 mL a.i.110 kg seed) or a spore suspension of lo6 spores/ml of Verticillium biguttatum or a dust with tolclofos methyl (4 g a.i.110 kg seed) were most effective if planted in soil fumigated with 500 L/ha metham sodium or soil with low levels of R. solani. A commercial formulation of Trichoderma harziannum and T. koningii applied as a dust at 1.3 g110 kg seed was in most cases ineffective when treated seed was planted into either fumigated or unfumigated soil. The incidence of progeny tubers with sclerotia varied between sites and ranged from 85% in an unfumigated soil planted with infected tubers to 2% in a fumigated soil planted with pencycuron-treated tubers. Except for 1 experiment where tubers were harvested early, neither seed treatments nor fumigation improved total nor marketable yield.

1978 ◽  
Vol 29 (6) ◽  
pp. 1127 ◽  
Author(s):  
JW Meagher ◽  
RH Brown ◽  
AD Rovira

Field trials in a sandy mallee soil in Victoria have shown that large increases (up to 323%) in grain yield are obtained by soil fumigation or the application of nematicides. Development of the plants was enhanced by control of soil-borne root pathogens. The occurrence of both cereal cyst nematode (H. avenae) and Rhizoctonia solani in patches of poor wheat in a field trial in South Australia indicate a possible association between these two pathogens. Glasshouse studies showed that the effects of H. avenae and R. solani on wheat were greater when both pathogens were together than with each individually.


Author(s):  
Lidija VOJEVODA ◽  
Anita OSVALDE ◽  
Gunta ČEKSTERE ◽  
Andis KARLSONS

Investigations on the potential beneficial effect of humic substances on crop plant cultivation under extremely diverse soil and climatic conditions is of global character, thereby knowledge obtained on the basis of local investigations are of great importance world-wide. The aim of the research was to evaluate the effect of different application methods (seed tuber treatment and foliar application) of commercially-produced peat and vermicompost extracts on nutrient uptake in tubers and yield of potato (Solanum tuberosum L.) using field experiments in organic farming system with potato variety ‘Borodjanskij Rozovij’. The tested extracts from the organic products included: peat extract (K45) and vermicompost extract (B45) obtained at +45°C by cavitation. The investigation was carried out at Stende Research Centre (Institute of Agro-resources and Economics) from 2011 to 2012. The chemical composition (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo, B) of potato tubers was determined. The application of organic extract from vermicompost had a stimulating effect on mineral nutrient as N, P, K, Mg, and S accumulation in potato tubers, but 50% of cases showed reduction in Ca and Cu content that could influence the storage of tubers. The use of peat extract was significantly effective when the tubers were treated before planting. On average, tuber treatment and foliar spray with organic extracts contributed to 10% of tuber yield increase.


1989 ◽  
Vol 29 (3) ◽  
pp. 439 ◽  
Author(s):  
TJ Wicks ◽  
AR Granger

Fungicides and insecticides used at the recommended rate, and reduced recommended rates were applied at low volume (100 L ha-1) to apple trees in field experiments in South Australia from 1985 to 1988. At harvest the incidence of fruit damaged by fungi and insects was assessed on Golden Delicious, Red Delicious, Jonathan and Granny Smith cultivars. Mixtures of penconazole and mancozeb applied at the recommended rates of 800 mL and 4.5 kg ha-1 respectively as well as 25% and 10% of the recommended rates controlled apple scab completely in 1986, but were less effective in 1987. Azinphos-methyl applied at the recommended rate of 2.7 kg and 25% of the recommended rate reduced codling moth infestation to commercially acceptable levels of <2 % on Red Delicious only in 1987. Considerable cost savings are possible by using low rates of pesticides. Our results suggest that the use of low rates is more applicable to low valued cultivars such as Jonathans and orchards with low levels of pest and disease.


1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop


Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Norman Muzhinji ◽  
James W. Woodhall ◽  
Mariette Truter ◽  
Jacquie E. van der Waals

Understanding the contribution of seed tuber- and soilborne inocula of Rhizoctonia solani AG 3-PT in causing potato disease epidemics is an important step in implementing effective management strategies for the pathogen. A 2-year study was conducted to evaluate the contribution of each source of inoculum using an integrative experimental approach combining field trials and molecular techniques. Two distinct sets of genetically marked isolates were used as seed tuberborne and soilborne inocula in a mark-release-recapture experiment. Disease assessments were done during tuber initiation and at tuber harvest. Both inoculum sources were found to be equally important in causing black scurf disease, whereas soilborne inocula appeared to be more important for root and stolon infection, and seedborne inocula contributed more to stem canker. However, seed tuber-transmitted genotypes accounted for 60% of the total recovered isolates when genotyped using three polymerase chain reaction restriction fragment length polymorphism markers. The changes in population structure of the experimental R. solani population over the course of the growing season and across two growing seasons were investigated using eight microsatellite markers. The populations at different sampling times were somewhat genetically differentiated, as indicated by Nei’s gene diversity (0.24 to 0.27) and the fixation index (FST). The proportion of isolates with genotypes that differed from the inoculants ranged from 13 to 16% in 2013 and 2014, respectively, suggesting the possibility of emergence of new genotypes in the field. Because both soilborne and tuberborne inocula are critical, it is important to ensure the use of pathogen-free seed tubers to eliminate seed tuberborne inoculum and the introduction of new genotypes of R. solani for sustainable potato production in South Africa.


2021 ◽  
Vol 845 (1) ◽  
pp. 012015
Author(s):  
E V Aminova ◽  
R R Salimova ◽  
O E Merezhko

Abstract Nowadays the study of the interrelation of the genotype of strawberry plants in garden and climatic conditions is extremely relevant. Due to the various systems of genetic control and the modifying effects of growing conditions on the manifestation of quantitative traits, there is the need to assess the genotypic variability of economically valuable features, focused on the identification of genotypes characterized by stability and adaptive qualities in growing conditions. The study examined 15 varieties of garden strawberries of domestic and foreign selection. The field experiments and surveys were carried out according to the Program generally accepted in the Russian Federation and methodology for the variety study of fruit, berry and nut crops. We studied such features as the number of peduncles (pcs/bush), number of berries (pcs/bush), average weight of berries (g), total and marketable yield (g/bush), sugar content in berries, soluble solids and ascorbic acid. The purpose of this work was to assess the genotype-year interrelation in terms of the variability of productivity features and berry quality and to identify strawberry varieties with a stable genotype. As a result of two-way analysis of variance for the variety-year interrelation, the obtained values were 1.10-8.50 at standard Fst. - 1.24. Statistically important differences had indicators of productivity of a bush between the first and second clusters (t = 5.89 at p <0.01), the first and third (t = 15.83 at p <0.01), the second and third clusters (t = 8.13 at p <0.01), as well as the average berry weight between the first and third, second and third clusters (t = 15.50 and 6.99 at p <0.01, respectively). Significant differences in the value of the Euclidean distance were revealed for varieties Mishutka (54.5), Daryonka (54.5), Pervoklassnitsa (58) realizing their productivity potential in different years of cultivation.


Author(s):  
Narendra Singh ◽  
Vikee M. Patel

Black scurf (Rhizoctonia solani) disease of potato is becoming prominent in many potato growing districts of Gujarat state which reduce quality and market value of the produce, resulting in economic losses. The field experiment was conducted during rabi season of 2014-15 in naturally infested field with scurf pathogen at Potato Research Station, S.D. Agricultural University, Deesa (Gujarat) with the objective to find out suitable management strategies for black scurf through organic approaches (bio-agents and organic amendments). Among different bio-agents (Trichoderma viride, T. harzianum. Pseudomonas fluorescens and Bacillus subtilis) tested against black scurf, the tuber treatment with 2 per cent boric acid spray along with tuber treatment with T. viride @ 10 g/kg seed before sowing recorded the lowest disease incidence (15.33 %) and index (0.38) with highest total tuber yield (324.68 q/ha) with maximum income `2,57,414/ha. When price computed with healthy and diseased tuber yield among treatments, the maximum income variation was (`92,986/ha) recorded by the same treatment followed by the tuber treatment with 3 % boric acid spray before sowing (`68,440/ha). In case of various organic amendments tested, soil application of mustard cake @ 10 q/ha registered minimum disease incidence (37.33 %) and disease index (0.66) as compared to rest of the organic treatment with highest total tuber yield (`327.20 q/ha) with maximum income `2,65,010/ha. When price computed with healthy and diseased tuber yield among treatments, the maximum income variation was (`1,12,990/ha) recorded by the same treatment followed by the neem cake @ 10 q/ha (`56,660/ha). These organic treatments can provide an effective and economical management of black scurf of potato for cultivaters.


2021 ◽  
Vol 6 (1) ◽  
pp. 826-835
Author(s):  
Habtamu Tegen ◽  
Mnuyelet Jembere

Abstract Although there is adequate information on the influence of plant population on root yield and size of carrot on flat and raised bed for rain fed production system, information on ridge-furrow bed preparation method is limited for irrigation production system. Therefore, in this study, field experiments were conducted for 2 years to determine the appropriate spacing of carrot on ridge-furrow carrot production practice under irrigation. Root yield increased significantly as the population increased. On the contrary, root size significantly decreased as population increased. The result of combined analysis over season and locations indicated that the narrowest spacing of 10 cm × 4 cm rows on the ridge and between plants, respectively, which accommodates 1,250,000 plants ha−1 gave significantly highest marketable carrot root yield of 26 t ha−1 followed by 22.6 t ha−1 with spacing of 20 cm × 4 cm which accommodates 1,000,000 plants ha−1, but it produced the smallest individual root weight of 83 g which is mostly preferred for household consumption unlike jumbo roots. Therefore, in terms of root sizes and marketable yield, the current study identified that spacing of 10 cm × 4 cm is optimum on ridge-furrow carrot production practices.


2013 ◽  
Vol 1 (No. 4) ◽  
pp. 139-152
Author(s):  
Zavadil Josef

The paper deals with optimisation of threshold suction pressure of soil water on light soils for early potatoes, early cabbage, late cauliflower and celery on the basis of results of small-plot field experiments with differentiated irrigation regime. Experiments were conducted in 2003&ndash;2005. Threshold suction pressures of soil water were identical for all crops: 15 kPa in treatment I, 30 kPa in treatment II, 60 kPa in treatment III, and 120 kPa in treatment IV. Precipitation, air temperature and relative humidity, global solar radiation, wind speed and direction were measured by an automated meteorological station. Reference and actual evapotranspiration was determined for the experimental crops according to FAO Paper No. 56 and by means of a biological curve (BC) in 2003&ndash;2005. To compare these two methods of calculation of actual evapotranspiration the soil moisture balance was found out. Based on the influence on marketable yield and proportion of the crop quality grades it is possible to determine the optimum threshold suction pressure on light loamy-sand soils in early potatoes, late cauliflower and cabbage 30 kPa and in celery 15 kPa. 80% of available soil water capacity (ASWC) corresponds to the threshold suction pressure 30 kPa, and as much as 96% of ASWC corresponds to 15 kPa. The seasonal irrigation depths determined on the basis of soil moisture balance, in which the crop evapotranspiration (ETc) is calculated either according to FAO 56 or by the BC, are substantially different from the really achieved irriga&shy;tion depths in the treatments where optimal suction pressure is maintained. For potatoes, the really achieved values of seasonal irrigation depths are nearer to the depths calculated by the BC, while for the other vegetables (cauliflower, cabbage and celery) they are more similar to the depths calculated by FAO 56 methodology. The theoretical irrigation depths calculated by the BC method sometimes differ substantially from those based on FAO 56. These differences are at maximum for cauliflower and celery and at minimum for cabbage and decrease with the decreasing irrigation depths.


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