CONTROL OF PHOMOPSIS BLIGHT OF EGG PLANT THROUGH FERTILIZER AND FUNGICIDE MANAGEMENT

The experiments were conducted at Laboratory of the Department of Plant Pathology and in the farm of Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh during Rabi season of the year 2007-2008. Four fungicides viz. Bavistin 50 WP (Carbendazim), Tilt 250 EC (Propiconazole), Cupravit 50 WP (Copperoxychloride) and Dithane M-45 (Mancozeb) and micronutrients (Gypsum, ZnO and Boric acid) were evaluated against Phomopsis vexans causing Phomopsis blight and fruit rot of eggplant. The fungicides and micronutrients either applied individually or in combination showed significant effect in terms of per cent leaf infection, fruit infection, leaf area diseased and fruit area diseased in comparison to control. Effect of each fungicide applied in combination with micronutrients always showed better performance in reducing disease incidence and disease severity than the fungicides applied alone. Among the fungicides, Bavistin 50 WP (0.1%) proved to be effective arresting the spore germination and mycelia growth of Phomopsis vexans assayed in in vitro test. Reduction of leaf area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 58.17, 67.37, 78.41 and 85.25%, respectively at preflowering, post-flowering, fruiting and fruit ripening stages while Bavistin 50 WP (0.1%) alone reduced by 52.22, 58.67, 74.19 and 83.09%, respectively at those stages. Similarly reduction of fruit area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 57.93 and 79.79%, respectively at fruiting and fruit ripening stages while Bavistin 50WP (0.1%) alone reduced by 56.93 and 76.14%, respectively at those stages. Micronutrients had little effect against the disease but significantly better than control.


Introduction
Eggplant (Solanum melongena) is an important vegetable in Bangladesh cultivated round the year in all districts of the country (Anonymous, 2001).The eggplant is of much important in the warm areas of Far East and grown extensively in India, Bangladesh, Pakistan, China and Philippines.It is thought to be originated in Indian sub-continent with the secondary centre of origin in China (Zeven and Zhukovsky, 1975).Eggplant is locally known as "Begun" and its early European name is Aubergine or Egplant.
Eggplant is nutritious and widely grown vegetable in Bangladesh as well as in the world and has multifarious use as a dish item (Bose and Som, 1986;Rashid, 1993).About 8 million farm families are involved in eggplant cultivation.Its position in terms of acreage production is second in vegetable crops (BBS, 2003).It is grown round the year both as winter (Rabi) and summer (Kharif) crops.Eggplant is thus regarded as a cash crop.The total acreage of eggplant is 44,377 acres with total annual production of 1,25,080 metric tons (BBS, 2010).A large number of cultivars are grown in Bangladesh, which show a wide range of variation in yield performance.This gives small, marginal and landless farmers a continuous source of income and provides employment facilities for the rural people.For most of the time, except peak production period, market price of eggplant compared to other vegetables remains high which is in favor of the farmer's solvency.Therefore, it plays a vital role to boost our national economy.
Eggplant suffers from 12 diseases of which Phomopsis blight and fruit rot caused by Phomopsis vexans has been treated as major constraints of its cultivation in our country (Das, 1998).The causal organism of the disease, Int.J. Agril.Res.Innov.& Tech. 3 (1): 66-72, June, 2013 Phomopsis vexans viable for about 14 months in soil debries and in the seed from infected fruits.The pathogen is reported both externally and internally seed borne.The disease was first reported from Gujrat in 1914 and since then from many parts of India.Fakir (1983) and Ahmad (1987) have reported occurrence of the disease in Bangladesh.The disease has become a major constraint in case of intensive cultivation of eggplant.The disease affects the crops from seedling to maturity (Singh, 1992).
Crop losses due to this disease are evident, loss ranges from 15-20% in general but 30-50% in severe case which estimated as a losses equivalent to TK. 1255 million ($20 million) per annum (BBS, 2003;Das, 1998).It is a serious disease, which may cause damping off symptoms if attacked at seedling stage.When the leaves are infected, small circular spots appear which become grey to brown with a light color centre.The infected leaves may turn yellow and die.Lesion may also develop on petiole and stem cause blighting of affected portions.In course of time, the spot enlarges and produces concentric circular area.Ultimately, the fruits become mummified and rotten (Kumar et al., 1986).There is no recognized resistant variety of eggplant against fruit rot disease.A very few works have been made by different workers to control this disease (Khan, 1999;Hawlader, 2003;Nazimuddin, 2004).Therefore, the experiment was undertaken to find out the effective fungicides or micronutrients in controlling phomopsis blight of eggplant.

Materials and Methods
The experiment were conducted at M.S. Laboratory during September-November' 2007 and in the farm allotted for the Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh during Rabi season of the year 2007-2008.In the laboratory experiments completely randomized design (CRD) was followed and the field experiment was laid out in randomized complete block design (RCBD) with three replications.There were 30 unit plots altogether in the experiment.The size of the plot was 3.0 m × 1.0 m, plant to plant distance was 0.  (Gomez and Gomez, 1984).Fertilizers and manures were applied as per recommendation of BARI (Bangladesh Agricultural Research Institute) ( (Anonymous, 1997).Watering and intercultural operations were done when necessary.In the laboratory, Potato Dextrose Agar (PDA) was made and poured into each Petri-plate (9 cm diameter) and allowed to solidify.The pathogen, Phomopsis vexans was isolated by tissue plating method from naturally infected brinjal fruit collected from the Horticulture garden of Sher-e-Bangla Agricultural University, Dhaka (Islam, et al., 2004).Infected tissues were cut and placed in PDA media and incubated at 22 ± 2ºC for 10 days and pycnidia were formed.Spore suspension inocula -1 of Phomosis vexans was prepared and suspension was adjusted to 10 5 conidia ml -1 solution and stored at 5˚C.Bioassay of fungicides was done by Cup/Groove method and Disc/Zone inhibition method.Seeds of eggplant cultivar Singnath were collected from Bangladesh Agricultural Research Institute (BARI), Joydebpur, and Gazipur and were treated with Vitavax-200 (0.2%) were sown in plastic trays containing sterilized sandy soil on18th November 2007.Main field was prepared and seedlings were transplanted on 16 January 2008 in accordance with the experimental design.Plant to plant distance was maintained 75 cm and each plot contain five plants.Phomopsis vexans was inoculated by spraying to the eggplant.After spraying, the seedlings of eggplant were covered with moistened polythene with the help of bamboo.Symptoms were developed on leaves and fruits in brinjal plants.Fungicidal suspensions were prepared and sprayed at flowering, fruiting, and post fruiting stages.After inoculation and spraying of fungicides, data were recorded at every 10 days intervals on % Leaf infection, % LAD (Leaf area diseased), % Fruit infection and % FAD (Fruit area diseased).
Per cent LAD (Leaf area diseased) and per cent FAD (Fruit area diseased) were measured by eye estimation.Area of single leaf/fruit was considered as 100%.Deducting the healthy area, the diseased area was estimated.Average % LAD/FAD was then calculated by dividing the total diseased areas by the investigated leaves/fruits (Islam, 2005a).The significance of the difference among the treatment means was estimated by DMRT (Duncan's Multiple Range Test) at 5% level of probability (Gomez and Gomez, 1984).

Isolation and identification of causal agent
The causal fungus was isolated from both infected leaves and fruits.Symptoms of Phomopsis blight and fruit rot caused by Phomopsis vexans as observed in the experimental plot conform with those reported by Walker (1952) from United States of America; Kumar et al. (1986) and Singh (1992) from India; Das (1998) and Islam (2005b) from Bangladesh.Walker (1952) described the first phase of the disease as blight of young seedlings.Islam (2005a) observed the fungus as whitish mycelial growth in cultured media with the presence of concentric growth sporadic pycnidia partially emerges in the media.Islam (2005b) also reported that pycnidia possessed both α & β conidia.

Laboratory experiment
Bavistin 50 WP (Carbendazim) was found promising against Phomopsis vexans in the laboratory assay.Bavistin (0.1%) completely arrested the mycelial growth and produced largest inhibition zones (6.29 cm) in culture media while assayed by food poisonic techniques following cup and disc method.The performance of Tilt 250 EC in controlling the mycelial growth of Phomopsis vexans was also promoting next to Bavistin 50WP.The performances of rest of the fungicides were less promising but significantly better than control.The results of the laboratory assay corroborate with the reports of Mohanty et al. (1994) and Islam (2005a).

Effect of fungicides and micronutrients at pre-flowering stage in the field condition
Effect of each fungicide applied in combination with micronutrients always showed better performance in reducing disease incidence and disease severity than the fungicides applied alone.
Significantly the lowest leaf infection (14.15%) was recorded in case of application of Bavistin 50 WP in combination with micronutrients (T7) followed by application of Bavistin 50 WP alone (T3) and application of Tilt 250 EC in combination with micronutrients (T10).The highest leaf infection (31.09%) was observed in case of control (T1) proceeded by application of micronutrients (T2), application of Cupravit 50 WP alone (T4) and application of Cupravit 50 WP in combination with micronutrients (T8).
The lowest leaf area diseased (6.12%) was recorded in case of application of Bavistin 50 WP in combination with micronutrients (T7) followed by application of Bavistin 50 WP alone (T3) and application of Tilt 250 EC in combination with micronutrients (T10).The highest leaf area diseased (14.63%) was observed in case of control (T1) proceeded by application of micronutrients (T2), application of Cupravit alone (T4) and Cupravit in combination with micronutrients (T8).

Effect of fungicides and micronutrients at post-flowering stage in the field condition
The fungicides and micronutrients either applied individually or in combination showed significant effect in terms of disease incidence (per cent Leaf Infection) and disease severity (per cent Leaf Area Diseased) in comparison to control.Significantly, the lowest leaf infection (13.65%), was recorded in case of Bavistin 50 WP in combination with micronutrients (T7) followed by Bavistin 50 WP alone (T3) and Tilt 250 EC in combination with micronutrients (T10).The highest leaf infection (39.51%) was observed in case of control (T1) preceded by application of micronutrients (T2), Cupravit alone (T4) and Cupravit in combination with micronutrients (T8).

Effect of fungicides and micronutrients at fruiting stage in the field condition
Effect of each fungicide applied in combination with micronutrients always showed better performance than the fungicides applied alone in reducing disease incidence and disease severity.
The lowest fruit infection (16.02%) was recorded in case of Bavistin 50 WP in combination with micronutrients (T7).The second highest performance in reducing fruit infection was recorded in case of Bavistin 50 WP alone (T3) followed by Tilt 250 EC in combination with micronutrients (T10) and Tilt 250 EC alone (T5).

Effect of fungicides and micronutrients at fruit ripening stage in the field condition
The fungicides and micronutrients applied either individually or in combination showed significant effect in terms of disease incidence (%LI and %FI) and disease severity (%LAD and %FAD) in comparison to control.Effect of each fungicide applied in combination with micronutrients always showed better performance in reducing disease incidence and disease severity than the fungicides applied alone.Significantly the lowest leaf infection (15.03%), was recorded in case of Bavistin 50 WP applied in combination with micronutrients (T7) that was followed by Bavistin 50 WP alone (T3), Tilt 250 EC in combination with micronutrients (T10) and Tilt 250 EC alone (T5).The highest leaf infection (90.31%) was observed in case of control (T1).The application of micronutrients alone (T2) showed significantly lower leaf infection than control preceded by Cupravit 50 WP alone (T4) and Cupravit 50 WP in combination with micronutrients (T8).
The effect of fungicides and micronutrients in reducing percent fruit infection (%FI) was more or less similar to that of percent leaf infection (%LI).The lowest fruit infection (15.57%) was recorded in case of Bavistin 50 WP applied in combination with micronutrients (T7) which was followed by Bavistin 50 WP alone (T3), Tilt 250 EC in combination with micronutrients (T10) and Tilt 250 EC alone (T5).The highest fruit infection (68.89%) was observed in case of control (T1) preceded by application of micronutrients (T2), Cupravit 50 WP alone (T4) and Cupravit 50 WP in combination with micronutrients (T8).
In case of per cent leaf area diseased (%LAD), the lowest leaf area diseased (4.38%) was recorded in case of Bavistin 50 WP applied in combination with micronutrients (T7) that was followed by Bavistin 50 WP alone (T3), Tilt 250 EC in combination with micronutrients (T10) and Tilt 250 EC alone (T5

Conclusion
Effect of each fungicide applied in combination with micronutrients always showed better performance in reducing disease incidence and disease severity than the fungicides applied alone.Bavistin 50 WP (0.1%) alone or in combination with micronutrients (Gypsum, ZnO and Boric acid) could be used for management of Phomopsis blight and fruit rot of eggplant.The enthusiastic researchers can be motivated to experiment on other fertilizers and fungicides for control of phomopsis blight of eggplant.

Table 1 .
Effect of different fungicides on inhibition of mycelia growth of Phomopsis vexans in the laboratory

Table 2 .
Efficacy of fungicides and micronutrients in controlling Phomopsis vexans causing leaf blight and fruit rot of eggplant at pre-flowering stage in the field condition

Table 3 .
Efficacy of fungicides and micronutrients in controlling Phomopsis vexans causing leaf blight and fruit rot of eggplant at post-flowering stage in the field condition

Table 4 .
Efficacy of fungicides and micronutrients in controlling Phomopsis vexans causing leaf blight and fruit rot of eggplant at fruiting stage in the field condition

Table 5 .
Efficacy of fungicides and micronutrients in controlling Phomopsis vexans causing leaf blight and fruit rot of eggplant at fruit ripening stage in the field condition Figures with common letters do not differ at p=0.05In field condition, Bavistin 50 WP (0.1%) in combination with micronutrients and Bavistin 50 WP (0.1%) showed promising performance in leaf infection, fruit infection, leaf area diseased and fruit area diseased applied as post inoculation spray at pre-flowering, post flowering, fruiting and fruit ripening stages.Reduction of leaf area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 58.17, 67.37, 78.41 and 85.25%, respectively at preflowering, post-flowering, fruiting and fruit ripening stages while Bavistin 50 WP (0.1%) alone reduced by52.22,58.67,74.19and 83.09% LAD, respectively at those stages.Similarly reduction of fruit area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 57.93 and 79.79%, respectively at fruiting and fruit ripening stages while Bavistin 50 WP (0.1%) alone reduced by 56.93 and 76.14% FAD, respectively at those stages.Bavistin 50 WP (0.1%) in combination with micronutrients control Phomopsis blight and fruit rot of eggplant somewhat more than Bavistin 50 WP (0.1%) alone but both are statistically similar.