Leaf Spot Disease Of Groundnut Research Articles

Identification of new sources of resistance against late leaf spot disease of groundnut using molecular and field screenings

ABSTRACT Late leaf spot (LLS), caused by the fungus Nothopassalora personata, is an important foliar disease in groundnut (Arachis hypogaea L.) production. The present study used previously reported three single nucleotide polymorphism (SNP) markers to screen a set of groundnut germplasm and compared them with phenotypic values of three hotspot locations. The results indicated that marker-identified genotypes had LLS-resistant or moderately resistant phenotypes. About 56% of the phenotypically confirmed genotypes were confirmed with the SNP genotype. Some of the phenotypically resistant genotypes were not confirmed with marker genotypes, indicating some other quantitative trait locus (QTL) responsible for the LLS resistance might have been involved. The findings in this study are relevant to future LLS resistance breeding programs.

Effect of Different Mulching Materials on Leaf Spot Disease of Groundnut

A study was conducted in summer season of 2020 and 2021 to evaluate the effect of different mulching materials on late leaf spot disease of groundnut caused by Phaeoisariopsis personata (Berk. & Curt.) v. Arx at Oilseed Research Program, Sarlahi, Nepal. The experiment was laid out in randomized complete block design (RCBD) with 7 treatments viz. rice husk, rice straw, black polythene sheet, Lantana camara, living mulch, sawdust and control in three replications with fertilizer dose 20:40:20 NPK kg per hectare. The disease was scored in 1-9 scale and severity and AUDPC was calculated. In 2020, Lantana camara mulched plot showed significantly the lowest disease severity and the lowest AUDPC value (66.67% and 1556) followed by rice husk (70.37% and 1556) and black plastic (70.37% and 1611) mulched plot. Similarly in 2021, Lantana camara mulched plot showed significantly lowest disease severity and the lowest AUDPC value (62.96% and 1500) followed by rice husk (66.67% and 1574) and black plastic (66.67% and 1574) mulched plot. Significantly the highest pod yield was obtained in rice husk mulched plot (2.35 t/ha in 2020 and 2.07 t/ha in 2021) followed by living mulch treated plot (2.13 t/ha in 2020 and 1.84 t/ha in 2021). The highest disease severity (81.4% same as rice straw and saw dust mulched plot) with highest AUDPC value (1981) was observed in plot with no mulch during 2020 where as in 2021, the highest disease severity (77.78 same as plot with no mulch) with highest AUDPC value (1889) was observed in rice straw mulched plot. This study shows that organic mulches like rice husk could be better option for reducing disease severity with better yield in groundnut.
 Int. J. Appl. Sci. Biotechnol. Vol 11(1): 37-41.

Leaf spot disease of groundnut: A review of existing research on management strategies

Leaf spot disease of groundnut: A review of existing research on management strategies

Field Efficacy and Phytotoxicity Evaluation of Metiram70 % WG against Tikka Disease in Groundnut

A field experiment was conducted during Kharif-2017 comprising six treatments which replicated four times under farmer’s field. During the current study an attempt was made to evaluate different doses of Metiram 70 % WG for effective management of Tikka leaf spot disease of Groundnut. The results from field experiment showed that, spraying of Metiram 70 % WG @ 2500 g/ha was found effective in registering the lowest leaf spot severity of 14.81 Percent Diseases Index (PDI) which was on par with Metiram 70 % WG @2000 g/ha of both market sample (15.03 PDI) and test sample (16.47 PDI). Data pertaining to percent disease control over untreated check was observed higher in Metiram 70 % WG @ 2500 g/ha (78.32 %). The highest pod yield was documented in plots applied with Metiram 70 % WG @ 2500 g/ha (3016.06 kg/ha) followed with Metiram 70 % WG @ 2000 g/ha of both market sample (2934.82 kg/ha) and test sample (2957.75kg/ ha). In perusal of information generated in the present investigation it is envisaged that, spraying of Metiram 70 % WG @ 2500 or Metiram 70 % WG @ 2000 g/ha were found to be effective dose of fungicides in the management of the disease under field condition as well as successfully suppressed the secondary spread after resorting curative measures.

Incidence of Cercospora Leaf Spot Disease of Groundnut (Arachis hypogaea L.) As Influenced by Sowing Date in Makurdi, Benue state of Nigeria.

Leaf spots of groundnut caused by Cercospora spp is one of the major economic production constraint militating against groundnut production in Nigeria. Field experiments were conducted during the 2011 and 2012 seasons at the Teaching and Research Farm of the Federal University of Agriculture, Makurdi Nigeria to assess the effect of sowing dates on the incidence of Cercospora leaf spot of groundnut The 2 x 4 x 3 factorial (2 groundnut varieties/ 4 sowing dates/ 3 replications) experiment was laid out in a Randomized Complete Block Design (RCBD) and replicated three times. Results indicated no significant effect of Cercoscora leaf spot on the two varieties in 2011 but in Ex-Dakar recorded a significantly (P < 0.05) higher leaf spot incidence compared Borno-Red variety. Sowing groundnut seeds in 14th June to 29th June recorded significantly higher (P < 0.0) leaf spot disease incidence compared with sowing groundnut seeds in May. Ex-Dakar variety recorded higher leaf defoliation compared with Borno-Red variety in 2012 and 2012 seasons. Results indicated that Borno-Red had a significantly (P < 0. 05) higher 100 seed weight in 2011, while Ex-Dakar recorded higher 100 seed weight in 2012. The results has proved that early sowing of groundnut in May can be employed as alternative strategy for the management of leaf spot disease of groundnut in Makurdi, NigeriaKey word: Groundnut, disease incidence, sowing date, leaf defoliation, leaf spot.

English

Groundnut (Arachis hypogea L.) is an important food source as well as cash crop for the people of Northern Ghana. The crop yield is low partly due to biological constraints which include diseases like leaf spot. A survey was conducted among 200 farmers in four districts of the Northern Region of Ghana, from June to August, 2014 using a structured questionnaire. The objectives of this study were to assess farmers’ knowledge, perception and management of leaf spot disease of groundnut. Differences in farmer responses were evaluated using Chi-square test. A significantly higher (P =0.005) number of farmers (87.5 %) were aware of leaf spot disease of groundnut and could identify symptoms of the disease, but could not differentiate symptoms from herbicide injury. Majority (84.5 %) of the farmers reported the incidence of leaf spot disease on their farms to be 50 % and above. Most farmers (74.5 %) also reported the disease severity to be above 50 %. Male farmers (33.5 %) who used defoliation or brown spots as signs of maturity of the groundnut crop were significantly more (P =0.031) than their female counterparts (26 %). Farmers who used non-chemical methods (62 %) of managing leaf spot disease were significantly (P <0.001) higher than those who used recommended methods including the use of chemicals (38 %). It is important to educate farmers to enhance their capabilities for leaf spot disease management through farmers’ field days. Also, since most of them use traditional methods such as crop rotation, appropriate spacing and mixed cropping as means of controlling the disease, and the use of effective plant extracts as an integrated management strategy would be ideal. Key words: Leaf spots, knowledge, perception, management, Northern region.

Implication of Fungicide Application Regimes and Post Spray Irrigation on Late Leaf Spot and its Residual Impact on Stem Rot of Groundnut

A field experiment was conducted during rabi season of 2015-16 and 2016-17 to study the efficacy of different protectant and systemic fungicides in different application regimes on late leaf spot disease of groundnut and to assess the impact of post spray irrigation timing on the severity of late leaf spot and as well as management of stem rot disease through deposition of foliar applied fungicides. Three sprays of chlorothalonil @ 2g/l (1th, 3rd, 5th) alternated with three sprays of pyraclostrobin @ 1g/l at 2nd, 4th and 6th spray (T8) reduced the highest disease severity (40.74%) as compared to seven spraying of chlorothalonil (T2) at 10 days interval (60.00%). The AUDPC values were significantly different among various treatments. Highest yield (28.89 q/ha) was also recorded in T8. The number of late leaf spot lesion decreased with the increase in gap between spraying and irrigation time. Irrigation after 96 h of fungicide spray caused only 2.02 leaf spot lesion per leaflet and highest pod colonization of 43.63% due to stem rot. Negative correlation was found between pod colonization and number of leaf spot lesion.

Evaluation of Three Botanicals, Bavistin and BAU-Biofungicide for Controlling Leaf Spot of Groundnut Caused by &lt;i&gt;Cercospora arachidicola&lt;/i&gt; and &lt;i&gt;Cercosporidium personatum&lt;/i&gt;

A study was conducted to evaluate the effectiveness of three selected botanicals namely leaf extract of Neem (Azadirachta indica), Debdaru (Polyalthia longifolia) and datura (black) (Datura metel) along with Bavistin (Carbendazim) and BAU-biofungicide (Trichoderma harzianum) against leaf spot disease (tikka) of groundnut caused by Cercospora arachidicola and Cercosporidium personatum at the Field Research Farm of Bangladesh Agricultural University, Mymensingh during 2009-10. The most effective treatments were Bavistin, BAU-biofungicide (seed treatment + spray), BAU-biofungicide (spray) and leaf extract of Neem. Bavistin increased pod and dry haulm yield by 53.51 and 24-80 %, respectively. Maximum pod yield and dry haulm weight were recorded under Bavistin. BAU-biofungicide (seed treatment + spray) produced the second highest pod and dry haulm yield followed by leaf extract of Neem and BAU-biofungicide (spray). BAU-biofungicide (seed treatment + spray) and leaf extract of Neem may be recommended for controlling leaf spot disease of groundnut. DOI: http://dx.doi.org/10.3329/agric.v12i1.19579 The Agriculturists 2014; 12(1) 41-49

Epidemiology of the Groundnut (&amp;lt;i&amp;gt;Arachis hypogaea&amp;lt;/i&amp;gt; L.) Leaf Spot Disease: Genetic Analysis and Developmental Cycles

Groundnut leaf spot is one of the important factors limiting groundnut productivity in Africa particularly in the Democratic Republic of Congo (DR Congo). Early and late leaf spot disease of groundnut caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton, respectively, can cause considerable yield losses without fungicide management. The main objectives of this research were to analyze plant and disease developmental cycles. Significant differences were observed among the groundnut varieties evaluated for resistance to the leaf spot disease. The results show that plant development cycle can be divided into three developmental stages. A first stage characterized by a low production of leaves, a second stage with a significant leaf development and finally a third stage with a reduction of leaves. Interestingly, the leaf spot disease cycle was also divided in three stages. The disease stage characterized by the highest level of symptom expression was not associated with the plant phase with the highest emerged leaves. Disease symptoms reached the highest pick only after the phase of intense leaf development. The molecular analysis revealed that all the groundnut varieties analyzed were genetically closely related even though they showed different reactions to the leaf spot disease.

Effects of Variety and Fungicidal Rate on &lt;i&gt;Cercospora&lt;/i&gt; Leaf Spots Disease of Groundnut in the Sudan Savanna

A field study was carried out at the University of Maiduguri Teaching and Research Farm during the 2006, 2007 and 2008 cropping seasons to evaluate the effects of variety and fungicidal rate on Cercospora leaf spot disease of groundnut. The experimental design used was Randomized Complete Block Design (RCBD) with twelve treatment combinations of three varieties of groundnut (Ex-Dakar, RRB and ICGV-86024) and four levels of fungicidal rate (0, 1, 2 and 4 kgha¡¥1 of fungicide mancozeb) replicated three times. Disease incidence and disease severity were significantly higher in Ex-Dakar and 0 kgha¡¥1, thus had lower yields. Higher seed and haulm yield were recorded by RRB, ICGV-86024, as well as 2 and 4 kgha¡¥1 as a result of lower disease incidence and severity.

Role of Fluorescent Pseudomonads in Plant Growth Promotion and Biological Control of Late Leaf Spot of Groundnut

Twenty strains of Pseudomonas fluorescens were evaluated for their potential in promoting plant growth and in the control of late leaf spot caused by Cercosporidium personatum in groundnut under greenhouse conditions. Seed treatment with P. fluorescens strain Pf1 recorded the highest germination percentage and the maximum plant height. Seed treatment with P. fluorescens Pf1 significantly controlled late leaf spot disease of groundnut and increased the pod yield. When the treated seeds were sown in soil, the antagonist colonized well in the groundnut rhizosphere. P. fluorescens Pf1 showed the maximum production of indole acetic acid in in vitro.

Influence of variety and intra-row spacing on &lt;i&gt;Cercospora&lt;/i&gt; leafspot disease of groundnut in Bauchi, Nigeria

Cercospora leafspot infection was analyzed for ten diverse groundnut varieties sown at two intra-row spacings during 1998 and 1999 rainy seasons at Bauchi, Nigeria. Significantly (P Cercospora leafspot were obtained at 50x30cm intra-row spacing. Spacing of 50x20cm however encouraged development of the disease. Late maturing and spreading types were resistant to Cercospora leafspot,compared to erect and early maturing types which are susceptible. Progress of Cercospora leafspot on groundnut was influenced by higher rainfall, relative humidity and low temperatures. Global Journal of Agricultural Sciences Vol. 4(2) 2005: 177-182

Management of late leaf spot of groundnut (Arachis hypogaea) with chlorothalonil‐tolerant isolates of Pseudomonas aeruginosa

Fifteen groundnut‐associated bacterial isolates that inhibited by &gt; 90% the in vitro conidial germination of Phaeoisariopsis personata, causal agent of late leaf spot disease of groundnut, were applied as a prophylactic spray (108 cfu mL−1) and tested for control of the disease in the glasshouse. Two groundnut seed‐associated bacterial isolates, GSE 18 and GSE 19, identified as Pseudomonas aeruginosa, reduced the lesion frequency (LF) by up to 70%. A 90‐day‐old peat‐based formulation of P. aeruginosa GSE 18 reduced LF measured 15 days postinoculation by up to 60%. Both P. aeruginosa GSE 18 and GSE 19 were tolerant to chlorothalonil (Kavach®) up to 2000 µg mL−1 in LB broth. In glasshouse trials, GSE 18 and GSE 19 tested in combination with reduced concentrations of chlorothalonil were highly efficient in management of the disease. The disease was completely controlled by chlorothalonil (&gt; 250 µg mL−1), and in the presence of GSE 18 or GSE 19, 100 µg mL−1 chlorothalonil was equally effective. Application of rifamycin‐resistant mutants of GSE 18 or GSE 19 together with chlorothalonil significantly increased the survival of these isolates in the groundnut phylloplane. In the field, a combination of GSE 18 and 500 µg mL−1 chlorothalonil reduced disease severity comparable to 2000 µg mL−1 chlorothalonil alone. Use of chlorothalonil‐tolerant pseudomonads together with a quarter concentration of the recommended field dose of chlorothalonil doubled pod yield compared with the untreated unsprayed control.

Chitin‐supplemented Foliar Application of Serratia marcescens GPS 5 Improves Control of Late Leaf Spot Disease of Groundnut by Activating Defence‐related Enzymes

AbstractChitinolytic Serratia marcescens GPS 5 and non‐chitinolytic Pseudomonas aeruginosa GSE 18, with and without supplementation of chitin, were tested for their ability to activate defence‐related enzymes in groundnut leaves. Thirty‐day‐old groundnut (cv. TMV 2) plants pretreated with GPS 5 and GSE 18 (with and without supplementation of 1% colloidal chitin) were challenge inoculated after 24 h with Phaeoisariopsis personata, the causal agent of late leaf spot (LLS) disease of groundnut. GPS 5 and GSE 18, applied as a prophylactic spray, reduced the lesion frequency by 23% and 67%, respectively, compared with control. Chitin supplementation had no effect on the control of LLS by GSE 18, unlike GPS 5, which upon chitin supplementation reduced the lesion frequency by 64%, compared with chitin alone. In a time course study the activities of chitinase, β‐1,3‐glucanase, peroxidase and phenylalanine ammonia lyase were determined for the different treatments. There was an enhanced activity of the four defence‐related enzymes with all the bacterial treatments when compared with phosphate buffer and colloidal chitin‐treated controls. In correlation to disease severity in bacterial treatments, chitin‐supplemented GSE 18 was similar to GSE 18, whereas chitin‐supplemented GPS 5 was much more effective than GPS 5, in activation of the defence‐related enzymes. The high levels of enzyme activities following chitin‐supplemented GPS 5 application continued up to the measured 13 days after pathogen inoculation.

Weather based operational plant protection of leaf spot disease of groundnut

Sensitivity of weather to the incidences of the leaf spot disease on groundnut was studied. Using data collected by PPQ &amp; S during regular survey in different parts of the country it was observed that the disease occurred more frequently in Andhra Pradesh, Karnataka, Gujarat and Maharashtra both in kharif and rabi seasons from 1988-1998. Weather systems causing drop in temperature associated with rainfall and overcast condition leading to increase in relative humidity favoured incidence of the disease particularly when the crop was in pod formation to maturity stages. Decrease in maximum temperature £30° C and increase in morning and afternoon relative humidity ³ 80% and 60% respectively under cloudy condition (2 - 8 okta) associated with rainfall were found to be congenial for the development of the disease in moderate to severe intensities. This weather based information along with field observations on incidence of this disease could be used to forewarn the incidence of the leaf spot disease on groundnut for taking plant protection measures at appropriate time through Agromet Advisory Service.

Infection efficiency of Phaeoisariopsis personata and the influence of different wetness patterns on germ‐tube growth of the pathogen

Controlled environment studies with Phaeoisariopsis personata, the causal agent of late leaf spot disease of groundnut (Arachis hypogaea), have shown that infection is enhanced if leaves are exposed to alternate wet and dry periods (intermittent wetness) compared with continuous wetness. Detailed investigations to elucidate this phenomenon revealed more germ tubes per conidium and more branching of germ tubes with intermittent wetness than with continuous wetness. With intermittent wetness there was clear evidence of tropic growth of germ tubes and branches towards stomata and subsequent penetration. With continuous wetness, germ tube growth did not appear to be directional and germ tubes commonly passed over the stomatal guard cells, therefore leading to relatively few stomatal penetrations. For both wetness regimes, stomatal penetrations continued to increase with increased leaf wetness for at least 6 days after inoculation and there was a linear relationship between the number of stomatal penetrations and the number of resultant lesions. Infection efficiency was markedly increased when the spore load was reduced to 0.1 conidia per cm2 (about one spore per leaflet).

Field performance of some selected fungicides in the control of Cercospora leaf spot disease of groundnut (Arachis hypagaca L.) in Ghana

Five fungicides, Benomyl, Carbendazim, Metiram, Tridemorph and Triphenyltin hydroxide, were tested over 3 and 4 years in the field as weekly and forthnightly foliar sprays and as seed-dressing chemicals against Cercospora leaf spot disease of groundnut. For spraying, concentrations of 0.2 per cent (Benomyl, Carbendazim, Triphenyltin hydroxide) and 0.3 per cent (Metiram and Tridemorph) were used. For seed-dressing, the rates were 3.0 g aJ./kg of seed (Benomyl, Carbendazim and Triphenyltin hydroxide) and 4.8 g a.i/kg of seed, (Metiram and Tridemorph). Benomyl and Carbendazim significantly reduced leaf spot incidence more than Triphenyltin hydroxide which, in turn, significantly reduced the disease more than Tridemorph and Metiram when sprayed weekly and fortnightly. Weekly spraying gave significantly higher yields than forthnightly spraying. Foliar spraying with the fungicides was significantly more effective (P=0.01) in controlling the disease and inceasing yield than seed-dressing. It is recommended that fortnightly foliar application of 0.02 per cent Benomyl or Carbendazim should be used to control leaf spot disease of groundnut caused by Cercospora arachidicola and Cercosporidum personatum,