Sprays Of Mancozeb Research Articles

Prevalence and Management of Post-harvest Rots of Apple in Himachal Pradesh

During a survey of post-harvest diseases of apple in Himachal Pradesh conducted during July to September 2021, fourteen different types of rots were observed. Among these, Penicillium expansum (blue mould) was most destructive with exclusive incidence of 43.8%. Surveys of different markets/stores of Himachal Pradesh revealed that the total losses due to apple decay at various locations varied from 7.80 to 21.93%. Ten important commercial varieties of apple were screened for their comparative susceptibility against fruit decay.Tydeman’s Early Worcester was found to be most tolerant to all the rot causing fungi with mean per cent rotting of 23.26%.Cow urine was found most effective in providing 79.21% growth inhibition of test fungi under study. The next best bio-products were Emblica officinalis (amla), Melia azadirach (darek) and Dodonaea viscose (mehandu) with per cent growth inhibition of 75.66, 73.59 and 68.48%, respectively. Under in vitro conditions, mancozeb (0.1%) was the most effective fungicide providing 84.83% growth inhibition. The efficacy of mancozeb as dip treatment at 0.1% concentration was judged to be significantly superior followed by 0.05% carbendazim with per cent control of 95.97 and 92.35%, respectively. Preharvest spray of mancozeb (0.3%) was highly effective in checking all the test fungi under different type of storage for 2 months. 1-methyl cyclopropene (MCP) fumigation of apple fruits immediately after harvesting for 12 hours was most effective in checking the test fungi under study providing 89.60% control.

Effects of Sowing Dates and Fungicide Application on Chocolate Spot (Botrytis fabae Sard.) Disease of Faba Bean (Vicia faba L.) in Western Ethiopia

Faba bean (Vicia faba L.) is a cool legume crop grown in the highlands of Ethiopia, and chocolate spot disease (Botrytis fabae Sard.) occurs in wide areas. There is a shortage of recorded data about the impact of chocolate spot disease on faba beans and their management practices in Ethiopia. The objectives of this study were to assess the influence of sowing dates and the frequency of foliar fungicide (mancozeb) application for the management of chocolate spots and determine the association of sowing dates with chocolate spot disease occurrence. The experiment was conducted in the 2019 and 2020 growing seasons at two locations in Shambu and Guduru, western Oromia, Ethiopia. The mean disease severity, AUDPC, and grain yield were found to be statistically significant differences ( P < 0.05 ) among the treatments at both locations and years. A highly negative correlation of AUDPC with a grain yield was obtained for both locations and years. A high infection rate, disease severity, AUDPC, and low grain yield were recorded from the unsprayed treatment. Three applications of mancozeb spray on the first July sowing date have effectively reduced disease severity and significantly increased yield. However, cost-effective and environmentally eco-friendly disease management is an issue that has to be further investigated.

Evaluation of Different Fungicides in Management of Early Blight Disease of Tomato Caused by Alternaria Solani

Ten fungicides, including five systemicat, 50, 100 and 200 μg mL−1 concentrations and five non-systemic fungicides at 500, 1000 and 2000 μg mL−1 concentrations were evaluated for their efficacy against Alternaria solani under in vitro conditions. Among non-systemic fungicides, both mancozeb 75 WP and propineb 50 WP proved highly toxic in inhibiting the mycelial growth. Among systemic fungicides, propiconazole 25 EC and tebuconazole 25 EC proved highly toxic. Two each of most effective, systemic and non-systemic fungicides under in vitro studies were evaluated under field conditions for managing the early blight disease. Under field conditions, the application was integrated with different planting dates in two cropping seasons of 2016 and 2017. The study revealed significant disease reduction in all treatments over control. The treatment combination 1st spray of mancozeb 75 WP @ 0.3% followed by 2nd spray of propiconazole 25 EC @ 0.05% was found to be most efficient in reducing the disease incidence and intensity from 46.0 and 21.8% in unsprayed check to 7.6 and 4.4% at all planting dates. Amongst different planting dates, disease progression was less when planted on 1st May followed by 20th May and 10th June.

Assessment of disease suppressing ability of some fungicides and Neem oil on for management of Alternaria blight disease linseed (Linum usitatissimum L.)

Alternaria lini and Alternaria linicola is known to cause destruction of host tissue through the reduction of photosynthetic potential by inciting spots and blights of the crops including linseed (Linum usitatissimum L.) Altrnaria blight of Linseed also reduces the oil content and quality of fiber of linseed. The present investigation was aimed to evaluate the efficacy of various fungicides and neem oil for management of this important disease. Three sprays of fungicides namely carbendazim 0.2%, mancozeb @ 0.2%, hexaconazole @ 0.1%, propiconazole @ 0.1%, tubaconazole 0.1%, kresoxin- methyl 0.1% and trichyclazole+mancozeb 0.1% and neem oil was done after the first appearance of the symptoms of Alternaria leaf blight. Minimum disease severity with maximum seed yield was recorded with three sprays of Mancozeb @ 0.2% followed by Propiconazole @ 0.1% and Hexaconazole @ 0.1%, respectively. Maximum seed yield (1443.75 kg./ha) was obtained with the spraying of Mancozeb @ 0.2% followed by Hexaconazole @ 0.1%. Good control was also obtained by the spray of carbendazim @ 0.2%, propiconazole @ 0.1% and hexaconazole @ 0.1%. Neem oil and @ 2% was found good for control of Altenaria blight pathogens and these could be used as substitute of chemical fungicides for ecofriendly management of Alternaria leaf spot.

Management of early blight of tomato by using different bioagents as seed dressing and its effect on germination and growth

Early blight of tomato caused by Alternaria solani (Ellis & Martin) Sorauer is one of the most destructive disease of tomato. It is a potential disease of tomato that reduces its production globally. Several management practices have been adopted so far to minimize the disease. Present study was based on screening of fungicides, bio agents and botanicals against A. solani in tomato causing early blight disease in glass house condition. Among six different treatments, T-6 treatment i.e. 2 per cent spray of mancozeb gives maximum disease control of 59.60 per cent followed by T-4 treatment having seedling treatment by Trichoderma harzianum with 50.98 per cent disease control. Disease severity was also in this study, which were 20.33 per cent given by treatment 6.

Evaluation of selected fungicides for the management of white rust of Indian mustard

Field studies were conducted to evaluate the efficacy ofselected fungitoxicants viz., mancozeb 75 WP @ 0.2%, metalaxyl 8%+ mancozeb 64% @ 0.2%, hexaconazole 5 EC @ 0.05%, cymoxanil 8% + mancozeb 64% @ 0.1%and azoxystrobin 23% SC 0.05% as a single spray treatment at 45 DAS and each four fungicides at 60 DAS in succession of mancozeb 75 WP at 45 DAS in control of white rust disease. The experiment was carried out for twoconsecutive years during rabi 2014-15 and 2015-16 with susceptible Indian mustard cultivar Varuna. All the fungicides tested were significantly effective in reducing the disease over the check; however the level of efficacy varied among the treatments. The plots sprayed with mancozeb (0.2%) at 45 DAS followed by azoxystrobin (0.05%) at 60 DAS recorded significantly lower disease severity over the other treatments both at leaf and staghead phasewith significant highest seed yield of 1906.81 kg/ha which was 42.33% higher over the check. The spray of mancozeb (0.2%) at 45 DAS followed by metalaxyl + mancozeb (0.2%) at 60 DAS was the next best treatment among combinations of two fungicidal sprays. Among single fungicidal spray treatments, spray of metalaxyl + mancozeb @ 0.2% was effective in reducing white rust at leaf and staghead phases with concomitant increase in seedyield. In general, none of the single spray treatments was found superior over the plots that received two fungicidal sprays i.e. mancozeb at 45 DAS followed by other fungicides at 60 DAS.

Efficacy of fungicides against Alternaria alternata causing alternaria blight of fennel

Fennel (Foeniculum vulgare Mill.) is a major seed spice crop, belongs to family Apiaceae (Umbelliferae). Fennel crop suffers from various diseases caused by fungi and other microorganisms. Amongst the major fungal diseases of fennel, the Alternaria blight caused by Alternaria alternata, is becoming a measure threat to the fennel cultivation. During present investigations six fungicides were evaluated against Alternaria alternata under in vitro and in vivo conditions. Among these fungicides, mancozeb + carbendazim (300 ppm) was found most effective in inhibition of mycelial growth (96.90%) and while in field, two spray of mancozeb + carbendazim (0.2%) was recorded highly effective in reducing disease intensity (71.53%) by increasing 73.07 per cent seed yield followed by mancozeb over unprotected control. The benefit cost ratio value was highest (1.95) with two sprays of mancozeb + carbendazim at 15 days interval followed by mancozeb (1.84).

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Field experiments were conducted in the Agricultural Research Institute, Uyole, using five susceptible maize varieties during 2013 and 2014 growing seasons. The varieties were used to determine yield losses due to northern leaf blight disease in Mbeya Region of Tanzania. The trials were laid out in two blocks of E. turcicum inoculated and Mancozeb treatment arranged in randomized complete block design in three replicates. Five fungicide sprays were done at weekly interval, starting from 35 days after planting (DAP) while disease inoculation was done twice at 35 and 45 DAP, using whorl placement technique. Data on disease severity index were collected using visual scale of 0-5, and grain yield of each treatment was recorded after harvest and drying. Such data were subjected to analysis of variance, correlation coefficient and coefficient of determination (R²). Means were separated using Turkey’s-Kramer simultaneous test at P≤0.05. Results indicated that Mancozeb sprays enhanced maize grain yield by 30 to 46.6% and 1000-grain weight by 19 to 24%. Disease severity index range of 78.7 to 95.7% indicated that Bora, Kilima, Situka-1, Staha and TMV-1 varieties were more susceptible to Northern leaf blight (NLB) disease. Yield losses ranged from 46 to 62.8% in grain yield (tons/ha) and 31.9 to 38.9% (g/plot) in 1000-grain weight. Disease severity index assessed at silking dry stage had a strong relationship to yield in all the varieties, but varied from Kilima (r = - 0.7617, R² = 0.580, P ≤ 0.078) in 2014 to Staha (r = - 0.9901, R² = 0.9803, P ≤ 0.001) in 2013 in grain yield. The minimum relationship between1000-grain weight and severity index of NLB was recorded in Staha (r = - 0.9300, R² = 0.8649, P ≤ 0.007) in 2013. The grain yield was enhanced and crop loss models indicated good fitness with strong and reliable validity in all the varieties, and as such can be used to estimate potential losses of maize caused by NLB disease in Mbeya, Tanzania.   Key words: Zea mays, northern leaf blight, yield loss, Tanzania. &nbsp

Determining Mancozeb Deposition Benchmark Values on Apple Leaves for the Management of Venturia inaequalis.

Apple scab, caused by Venturia inaequalis, is the most common fruit and foliar disease in commercial apple production worldwide. Early in the production season, preventative contact fungicide sprays are essential for protecting highly susceptible continuously unfolding and expanding young leaves. In South Africa, mancozeb is a key contact fungicide used for controlling apple scab early in the season. The current study developed deposition benchmarks indicative of the biological efficacy of mancozeb against apple scab, using a laboratory-based apple seedling model system. The model system employed a yellow fluorescent pigment that is known to be an effective tracer of mancozeb deposition. A concentration range of mancozeb (0.15 to 1 times the registered dosage) and fluorescent pigment concentrations was sprayed onto seedling leaves, which yielded various fluorescent particle coverage (FPC%) levels. Modeling of the FPC% values versus percent disease control yielded different benchmark values when disease quantification was conducted using two different methods. Thermal infrared imaging (TIRI) disease quantification resulted in a benchmark model where 0.40%, 0.79%, and 1.35 FPC% yielded 50, 75, and 90% apple scab control, respectively. These FPC% values were higher than the benchmarks (0.10, 0.20, and 0.34 FPC%, respectively) obtained with quantitative real-time PCR (qPCR) disease quantification. The qPCR benchmark model is recommended as a guideline for evaluating the efficacy of mancozeb sprays on leaves in apple orchards since the TIRI benchmark model underestimated disease control. The TIRI benchmark model yielded 68% disease control at the lowest mancozeb dosage, yet no visible lesion developed at this dosage. Both benchmark models showed that mancozeb yielded high levels of disease control at very low concentrations; for the qPCR benchmark model the FPC% value of the FPC90 (90% control) corresponded to 0.15 times that of the registered mancozeb concentration in South Africa, i.e., 85% lower than the registered dosage.

Field efficacy of different combinations of Trichoderma harzianum, Pseudomonas fluorescens, and arbuscular mycorrhiza fungus against the major diseases of tomato in Uttarakhand (India)

Tomato is one of the major cash crops in the Golapar area of district Nainital in Uttarakhand (India), where farmers are facing the problem of diseases in tomato cultivation. In the present investigation, a survey of tomato fields in the Golapar area of Haldwani block was conducted. The survey revealed the occurrence of late blight, early blight, stem rot, and wilt diseases causing an average loss of 80% to tomato. To counter the above diseases, Trichoderma harzianum (Th43), Pseudomonas fluorescens (Pf173), Jas mycorrhiza (AMF), and the fungicide (Mancozeb) in different combinations applyed through soil application (SA), seedling treatment (ST), and foliar spray (FA) were evaluated for growth promotion and disease control in tomato at experimental and farmers’ fields. The results of the study revealed that in experimental field, the maximum plant height (43.67 cm), highest number of branches (7.33) per plant, highest weight of fruit (47 g), highest number of fruits (39) per plant, minimum plant mortality (4% at 30 DAT and 3.2% at 30–60 DAT), minimum plant disease index (6.85), maximum total yield (256.00 q/ha), and marketable yield (246.67 q/ha) were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS). At farmer’s field, minimum plant mortality (7.31%) at 30 days after transplanting (DAT) (5.73%) in 30–60 DAT, minimum plant disease index (11.47), and maximum yield 249.91 q/ha were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS) combination. So, it can be concluded that among all the treatments, integrated treatment comprising of soil application of T. harzianum, P. fluorescens, Jas mycorrhiza (AMF) + seedling treatment with T. harzianum and P. fluorescens + three foliar sprays of Mancozeb was found very effective in reducing the plant mortality, promoting the plant growth, and increasing the yield at experimental field as well as at farmers’ fields.

Management of Septoria Tritici Blotch (<i>Septoria tritici</i>) of Bread Wheat (<i>Triticum aestivum</i> L.) in the Central Highlands of Ethiopia

Septoria tritici blotch (STB) is an economically important foliar disease in the major wheat-growing areas of Ethiopia. The current research was conducted to determine the impact of wheat varieties and fungicides on disease development and wheat yield. Besides, the effect of bread wheat varieties and fungicides on STB development, wheat yield was evaluated at Holleta and Kulumsa in a factorial field experiment involving three bread wheat varieties and six fungicide spray schedules. At Holetta, variety Kekeba had the highest AUDPC (2548) value followed by Madawalabu and Alidoro; whereas at Kulumsa the highest AUDPC (1509) was recorded on variety Madawalabu followed by Alidoro and Kekeba varieties. STB incidence and severity were significantly reduced by the application of fungicides across varieties but fungicide-variety combinations had differential effects on disease development. Wheat grain yields were the lowest from unsprayed plots regardless of variety and location. Kekeba variety treated with Mancozeb-Tilt-Mancozeb-Tilt (MTMT) fungicide combination produced the highest yield (5.05t/ha). The highest (577.31%) and lowest (-19.95%) marginal rate of return were obtained from Tilt and MTMT sprayed fields at Holetta planted with Kekeba and Madawalabu varieties, respectively. On the other hand, at Kulumsa, the highest marginal rate of return (886.88%) and the lowest marginal rate of return (-63.98%) was obtained from Tilt and Mancozeb sprays on Madawalabu and Alidoro varieties, respectively. The present findings confirmed the importance of STB in Ethiopia and the role fungicides play in managing the disease on partially resistant varieties.

Evaluation of different fungicides and antagonists In vitro and In vivo condition against Alternaria blight of pigeonpea

Efficacy of bio agents and systemic and non-systemic fungicides @ 50, 100, 200, 250 and 500 ppm were evaluated In vitro against Alternaria tenuissima causing Alternaria blight of pigeonpea. The relative efficacy of bio agents were studied in dual culture plate method showed that Hypocrea rufa was found most effective antagonist against test pathogen followed by T. harzianum. Efficacy of six fungicides was tested in poisoned food technique. Among the six fungicides tested, mancozeb was found most effective against test pathogen followed by Chlorothalonil and Iprodione. Propineb was least effective against mycelial growth of test pathogen. Raise in concentration of fungicides was more effective in inhibiting the mycelial growth of the pathogen. Field condition studies were found out to be the effect of seed treatment, foliar spray, seed treatment+ foliar spray with six fungicides and two bio agents and their combination used as against pathogen. Artificial inoculation of mass culture of A. tenuissima was done in the inoculated seed treatment and after foliar spray on the plants sixty DAS. Amongst them twenty five treatments, combination of Mancozeb with H. rufa was found most effective in reducing the disease intensity and disease control followed by Mancozeb with T. harzianum and Mancozeb alone, respectively. While, T. harzianum alone was least effective and maximum disease intensity recorded as a compared to control followed by T. harzianum with double dose and T. harzianum and H. rufa combination treatment, respectively. In case of both seed treatment and foliar spray of Mancozeb with H. rufa was found most effective in reducing the disease intensity and disease control followed by combination of Mancozeb with T. harzianum and Mancozeb alone, respectively. Whereas, least effective and maximum disease intensity and disease control were observed T. harzianum alone as compared to control.

Correlation coefficient between early blight severity, infection rates and meteorological factors in potato under different fungicidal spray

Early blight caused by Alternaria solani is a severe constraint in potato production. The severity of this disease has been increasing day by day for last few years in India due to changes in weather. Disease severity and area under disease progress curve (AUDPC) was recorded in each treatment plot. The early blight disease had significant negative correlation with maximum relative humidity during 2012-13 and in year 2013-14 minimum temperature was significantly correlated. The severity of early blight showed significant positive correlation with maximum temperature and highly significant positive correlations with sun shine hours in year 2013-14 in all tested treatments. The study showed that minimum temperature and rainfall revealed negative but non-significant correlation in all treatments except untreated control in year 2012-13. The maximum tuber yield 223.70 and 222.00 q/ha in first and second years, respectively, were recorded with spray of Fenamidone @ 0.2% at disease initiation and 2nd spray of Mancozeb @ 0.25% followed by Mancozeb @ 0.25% at 15 days intervals in both respective years.

Rainfastness of mancozeb on apple seedlings determined through deposition quantification of mancozeb residue and a fluorescent pigment

Mancozeb spray deposition and the persistence thereof to rainfall are important factors influencing the efficacy of apple scab control caused by Venturia inaequalis. Fungicide deposition can be assessed through quantification of fungicide residue, or fluorescent pigment quantification. Fluorescent pigment quantification is a more cost effective and less labour intensive method, since it is assessed using only photomacrography and image analyses. The yellow fluorescent pigment used in this study was shown to be a suitable tracer for five different mancozeb formulations on apple leaves when evaluated at different concentrations (0.5, 1.0, 1.5 and 2.0). Pearson's correlation was significant (P < 0.001) and high (r = 0.896) between fluorescent particle coverage (FPC%) and mancozeb residue (mg/kgDry Weight) for all five formulations. The particle size ranges of two wettable powder (WP) formulations were significantly smaller than those of the other WP formulations, but this did not result in differences in mancozeb residue on apple leaves. The persistence of mancozeb to different rain volumes applied to apple leaves was determined for three mancozeb formulation treatments: Dithane M-45 800 WP NT, Ventum 800 WP, and Ventum 800 WP combined with the sticker-spreader adjuvant Nu-Film P. There were no significant differences (P > 0.495) between the three treatments based on FPC% and mancozeb residue quantity when simulated rain was applied to apple seedlings at a constant rainfall intensity of 5 mm/h at five different rainfall volumes (0, 1, 5, 10 and 15 mm). A fair to good correlation (r = 0.697 and 0.995) existed between FPC% and mancozeb residue, and their percentage loss at different rainfall volumes. However, the response of FPC% and mancozeb residue differed based on exponential regression curves. This was due to a markedly larger predicted loss by each model's asymptote, 51.67% for FPC% and 40.76% for mancozeb residue. Based on actual mancozeb residue values, a significant percentage loss in residue already occurred after applying 1 mm (32.90%) rain. When rain volumes were increased to 5 and 10 mm rain, the percentage losses (37.88 and 41.08%) did not differ significantly from 1 mm rain. The same was true for percentage loss in FPC%, except that a significant higher loss occurred at 10 mm (52.36%) than at 1 mm rain (41.13%).

Assessment on management of late blight in tomato incited by Phytophthora infestans

Late blight incited by Phytophthora infestans is one of the most widely spread and economically important disease of potato. The present investigation was carried out to evaluate the efficacy of different fungicides and biocontrol agents for the management of the disease. Soil application of Trichoderma viride and Pseudomonas fluorescens 15 days before transplanting followed by prophylactic spray of Mancozeb (0.25%) 35 days after transplanting was found effective. Three sprays of fungicides viz ., Fenamidone + Mancozeb (0.3%), Iprovalicarb + Propineb (0.3%) and Dimethomorph (0.1%) + Mancozeb (0.2%) sprayed at regular intervals of seventh, ninth and eleventh weeks depending on the disease severity was found very effective in managing the disease.

INTEGRATED MANAGEMENT OF CHOCOLATE SPOT (BOTRYTIS FABAE) DISEASE OF FABA BEAN (VICIA FABA L.) IN ETHIOPIA: A REVIEW

The primary producers of pulses are small-scale farmers with small and dispersed plots under rain-fed conditions with substantially lower yields of less than 0.9 t/ha as compared to the improved faba bean varieties and international yields. There are many biotic and abiotic factors which hampers faba bean production in Ethiopia. From biotic factors chocolate spot (Botrytis fabae Sard.) is the major fungal disease hampering faba bean production in Ethiopia.). It is a highly prevalent and destructive disease, causing yield loss up to 61% on a susceptible and 34% on tolerant faba bean genotypes in the central highlands. But we can manage this economically important disease in manner which comprises all available diseases management methods in combination that is IPM (Integrated Pest management). So, the objective of this review work was to review available integrated pest management option for management of chocolate spot disease of faba bean in Ethiopia. We can control the disease by using different methods from these late sowing of faba bean, mixed cropping of faba bean with cereal crops and mancozeb spray reduced the disease and increased the grain yield and seed weight over sole and mixed cropping with field pea; also cereal mixing with faba bean has advantages over faba bean mixing with field pea. Suppressive effects can be ascribed to a combination of host biomass reduction, altered microclimate and physical barriers to spore dispersal. Also creation of a physical barrier in the form of non-host plants prevents some of the dispersed spores from being deposited on the host tissue by interception. In Ethiopia, study has revealed that the biological control agents for chocolate spot of faba bean and Bacilli are natural residents of faba bean leaves. Additionally recommendation have been given that, further study has to be done to explore the mode of action by bacillus subtilis against fabae.

Integrated management of late blight of potato

Late blight of potato is the major biotic constraint responsible for reduction in yield and quality of the pota-to crop. Globally, late blight is managed through application of multiple fungicidal chemical sprays affecting both human health and environment. Now a days, methods of biological control are gaining importance as these are non-toxic and also environment friendly. However, Phytophthora infestans multiplies very fast; therefore, biological con-trol method alone is not a viable option to manage late blight. Hence, integration of both methods is essential. Eleven treatments consisting of biocontrol agents and fungicides were evaluated against the late bight in three consecu-tive seasons (2011-12, 2012-13, 2013-14) at ICAR-CPRIC, Modipuram. Meerut. The results revealed that the treat-ments ( T1 to T10) are effective for managing the disease up to certain level; however, lowest average disease se-verity (27.89%) was recorded in treatment when Bacillus subtilis (B5-0.25%) + Trichoderma viride (TV-0.7%) was applied before disease appearance followed by cymoxanil8+mancozeb 64%WP (0.3%) at onset of late blight and one more spray of B5+ TV after seven days. The next best treatment was application of B5+ TV before appearance of disease followed by metalaxyl 8+mancozeb 64%WP (0.25%) at onset of late blight and one more spray of B5+ TV against control (average disease severity 91.94%) with higher yield also except the treatment of three spray of mancozeb 75% WP (0.2%). These treatments could be integrated in farmer practices.

Evaluating spray programs for managing copper resistant Pseudomonas syringae pv. tomato populations on tomato in the Limpopo region of South Africa

Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato is an economically important disease in the Limpopo production region of South Africa. Two field trials were conducted to evaluate different spray programs for management of the disease. In the first trial, applications were only made in the field, and the main product evaluated was acibenzolar-S-methyl (ASM), with and without copper + mancozeb. In the second trial, spray programs were already started in the nursery and then continued in the field. The main products evaluated in the second trial were ASM and biological products. In the first trial, ASM field programs included a South African registration (3.75 g/100 L every 21 days), a USA registration (1.16 g/100 L to 2.63 g a.i./100 L every 14 days) and an ASM low rate (1.16 g/100 L weekly) application. These spray programs were all effective, and comparable in suppressing foliar infections and severely infected fruit (fruit with more than five lesions). The addition of copper + mancozeb to ASM spray programs did not improve control. In most of the first and second set of trials, the commercial standard of weekly applied copper + mancozeb was ineffective in suppressing foliar and fruit damage. It furthermore resulted in a significant increase in fruit infections in most trials. The ineffectiveness of copper + mancozeb spray programs, and programs that contained these compounds, were due to copper resistant P. syringae pv. tomato strains. The strains were identified in all trials through in vitro copper sensitivity testing. This was further confirmed through a tomato seedling bioassay using a copper resistant strain. In the second trial, starting spray programs in the nursery was beneficial. ASM applications in the nursery, followed by ASM + copper + mancozeb field applications were more effective in suppressing fruit infections, compared to only field applications of the latter products. The application of B. subtilis in the nursery, followed by field applied biologicals (B. subtilis and Microbacterium maritypicum) combined with ASM sprays, also improved the reduction of infected fruit, when compared to field only applications of ASM + copper + mancozeb.

Efficacy of New Fungicides against Late Blight of Potato in Subtropical Plains of India

The field efficacy of metiram 55%+pyraclostrobin 5% WG, iprovaliadacarb 5.5%+propineb 61.25% WP, dimethmorph 50% WP, dimethmorph 50% WP+ mancozeb 75%, WP, famoxadone16.6+cymoxanil22.1% SC along with existing standard fungicides were evaluated for management of late blight during 2012-15. The results revealed that treatment mancozeb 75% WP (0.2%- before appearance) followed by two more spray with mancozeb 75% WP (0.2%) +dimethomorph 50% WP (0.2%) at 7-10 days intervals showed less terminal disease severity (24.55%) with highest disease controlled (74.45%), which was at statistically par with treatment mancozeb75% WP (0.2%, before appearance) followed by cymoxanil 8+mancozeb 64 % WP (0.3%) with two more spray at 7-10 days intervals, with 27.56% terminal disease severity along with disease controlled 71.29%. The highest tuber yield (28.74t/ha) was observed with mancozeb75% WP (0.2% before appearance) followed by two more spray with dimethomorph 50% WP (0.2) at 7-10 days intervals with followed by 28.12 t/ha with mancozeb 75% WP (0.2%- before appearance) followed by two more spray with mancozeb 75% WP (0.2%) +dimethomorph 50% WP (0.2%) at 7-10 days intervals. One spray of mancozeb (contact fungicides: before appearance) and latter two sprays of translaminar/systemic+contact fungicides at 7-10 days interval give better results for management of late blight of potato.

Feasible Management of Southern Corn Leaf Blight via Induction of Systemic Resistance by Bacillus cereus C1L in Combination with Reduced Use of Dithiocarbamate Fungicides.

Dithiocarbamate fungicides such as maneb and mancozeb are widely used nonsystemic protectant fungicides to control various plant fungal diseases. Dithiocarbamate fungicides should be frequently applied to achieve optimal efficacy of disease control and avoid either decline in effectiveness or wash-off from leaf surface. Dithiocarbamates are of low resistance risk but have the potential to cause human neurological diseases. The objective of this study was to develop a strategy to effectively control plant disease with reduced use of dithiocarbamtes. Southern corn leaf blight was the model pathosystem for the investigation. When corn plants were drench-treated with Bacillus cereus C1L, a rhizobacterium able to induce systemic resistance in corn plants against southern leaf blight, frequency of spraying dithiocarbamate fungicides could be decreased. The treatment of B. cereus C1L was able to protect maize from southern leaf blight while residues of dithiocarbamates on leaf surface were too low to provide sufficient protection. On the other hand, frequent sprays of mancozeb slightly but significantly reduced growth of corn plants under natural conditions. In contrast, application of B. cereus C1L can significantly promote growth of corn plants whether sprayed with mancozeb or not. Our results provide the information that plant disease can be well controlled by rhizobacteria-mediated induced systemic resistance in combination with reduced but appropriate application of dithiocarbamate fungicides just before a heavy infection period. An appropriate use of rhizobacteria can enhance plant growth and help plants overcome negative effects caused by dithiocarbamates.