Mango (Mangifera indica L: Anacardiaceae) is regarded as the most liked fruit in tropical and sub-tropical regions of the world. Powdery mildew of mango caused by Oidium mangiferae Bert. is one of the major plant pathological constraints in growing healthy mango orchards. The apparent symptoms of the disease occurred on young tissues of all parts of flowers, leaves and fruits. Severe blossom infection could result in complete damage to fruit; flower failed to open and drop off from the inflorescence. The inflorescence revealed a pattern of disease from tip to downward and showed itself by the emergence of wefts of white mycelium on the affected parts. Twenty-five mango varieties i.e. Langra, Dusehri, Ratole No.12, Fajri, Sindhri, Chaunsa Samar Bahisht, Anwar ratole, Neelam, Yakta, Tota Pari, Sensation, Saroli, Malda, Ghulab e Khas, Chaunsa Black, Chaunsa white, Anmol, Almas, Shan e Ali, Shan e Mustafa, Mahmood Khan, Armughan, Zafaran, Malda Late and Early Gold were evaluated through the observation of symptoms on young inflorescence to determine the disease incidence, disease severity index and average yield of fruit. The study was carried out in a randomized compete block design with twenty-five treatments and three replications. The mango varieties presented different performance in relation to powdery mildew incidence and could be categorized into eight groups. Maximum disease incidence was observed (33.33%, 26.66% and 26.66%, 26.66%) on Dusehri, Chaunsa Samar Bahisht, Malda and Ratole No.12 respectively and minimum disease incidence was (3.66% and 3.66%) noted on Almas and Sensation. These two varieties showed to be tolerant against the disease. It might be concluded that the presence or absence of symptoms caused by the powdery mildew had no such effect on the fruit yield of the mango cultivars.
Mango (Mangifera indica L.) is considered the king of fruit among tropical and subtropical regions of the world. In Pakistan, mango is cultivated on an area of 167.5 thousands hectares with the average production of 1732 thousand tones [
The study was conducted in (February-March) 2011 at the Bhatti Mango Farm in Faiz Pur Bhattian, located (30.270˚N and 71.250˚E, 122 m altitude from sea level) in the mango zone of Punjab i.e. Multan with a collection of various mango varieties. In general twenty five mango varieties viz. Langra, Dusehri, Ratole No.12, Fajri, Sindhri, Chaunsa Samar Bahisht, Anwar Ratole, Neelam, Yakta, Tota Pari, Sensation, Saroli, Malda, Ghulab e Khas, Chaunsa Black, Chaunsa White, Anmol, Almas, Shan e Ali, Shan e Mustafa, Mahmood Khan, Armughan, Zafaran, Malda Late and Early Gold were assessed. The orchard was well administered by following the conventional cultural practices.
The most obvious symptoms of mango powdery mildew were white superficial powdery mycelium on inflorescence, leaves and young fruits. The infection of Powdery mildew was evaluated to determine the disease incidence percentage and diseases severity index by modifying the scale for anthracnose on inflorescence for the field experiments [
Scale for powdery mildew of mango.
Score | Visual observation | Response |
---|---|---|
0 | No infection | Resistant |
1 | 0.1% - 7.0% | Tolerant |
2 | 7.1% - 15.0% | Moderately susceptible |
3 | 15.1% - 25.0% | Susceptible |
4 | 25.1% - 100.0% | Highly susceptible |
Powdery mildew was evaluated in 26/02/2011 by the visual observations of symptoms on the young flowers. The experiment was conducted in a randomized complete block design (RCBD); comprising of twenty five treatments and three replications. Ten inflorescence per plant served as one replication. The disease severity index and the average produce of the three plants of each variety were evaluated at the time of maturity i.e. harvesting of the crop in the month of June and July by the statistical analysis.
Data regarding disease severity index of all the varieties and average fruit yield of each variety was subjected to statistical analysis using the analysis of variance (ANOVA). Treatments means were compared by the Duncan New Multiple Range test (DMRT) at (P ≤ 0.05) via SAS (Statistical Analysis System, version 9.1). Incidence data, i.e. the percentage of inflorescence with powdery mildew, were transformed before analysis using the angular transformation (i.e. arcsine of the square root of the percentage) when required.
The results with reference to the powdery mildew of mango on flowers indicated that almost all the varieties were susceptible to the powdery mildew and showed a varying degree of infection percentage (
Powdery mildew has become more common and important disease in most of the mango growing areas of the world [
. Powdery mildew incidence, severity and fruit yield in mango varieties
Varieties | Powdery mildew* incidence percentage/3 plants | Powdery mildew severity index on selected variety | Response | Yield average fruit/ 3 plants |
---|---|---|---|---|
Langra | 16.66 (3.33,23.66) | 4.93ab | S | 171abc |
Dusehri | 33.33 (6.66, 46.66) | 6.89a | HS | 180ab |
Ratole No.12 | 26.66 (11.66, 36.66) | 6.80a | HS | 189ab |
Fajri | 23.33 (6.66, 33.33) | 6.12ab | S | 158abc |
Sindhri | 23.33 (3.33, 26.66) | 6.55ab | S | 147abcd |
Chounsa Samar Bahisht | 26.66 (11.66, 33.33) | 6.69ab | HS | 189ab |
Anwar Ratole | 6.66 (3.33, 23.66) | 4.92ab | T | 168abc |
Neelam | 6.66 (3.33, 18.33) | 5.89ab | T | 178ab |
Yakta | 6.66 (0.00, 11.66) | 4.11ab | T | 148abcd |
Totapari | 11.66 (6.66, 33.33) | 5.68ab | MS | 174abc |
Sensation | 3.66 (3.33, 26.66) | 3.93ab | T | 132bcd |
Saroli | 16.66 (11.66, 36.66) | 5.07ab | S | 162abc |
Malda | 26.66 (3.33, 43.66) | 6.11ab | HS | 151abcd |
Gulab e Khas | 11.66 (0, 23.66) | 4.93ab | MS | 159abc |
Chaunsa Black | 6.66 (0, 11.66) | 4.73ab | T | 159abc |
Chaunsa White | 11.66 (0, 23.66) | 3.48ab | MS | 156abc |
Anmol | 6.66 (0.00, 11.66) | 5.48ab | T | 143abcd |
Almas | 3.66 (3.33, 26.66) | 3.70ab | T | 196a |
Shan e Ali | 6.66 (0, 11.66) | 3.73ab | T | 152abcd |
Shan e Mustafa | 13.33 (3.33, 26.66) | 5.11ab | MS | 155abc |
Mahmood Khan | 13.33 (3.33, 21.66) | 5.14ab | MS | 170abc |
Armughan | 6.66 (0, 11.66) | 4.93ab | T | 92d |
Zafaran | 16.66 (6.66, 26.66) | 5.37ab | S | 113cd |
Malda Late | 16.66 (3.33, 23.66) | 5.37ab | S | 193ab |
Early Gold | 16.66 (3.33, 23.66) | 5.89ab | S | 140abcd |
Averages followed by the same letter in severity index and yield of fruit column do not differ statistically from each other (P ≤ 0.05), SE = 0.72, 16.05. T = tolerant, S = susceptible, MS = moderately susceptible, HS = highly susceptible. *Average incidence (minimum incidence, maximum incidence).
incidence percentage, the varieties showed eight different infection levels. In the first group, Dusehri was present with the maximum infection (33.33%). In the second group, Chaunsa Samar Bahisht and Ratole No.12 were present with the infestation of (26.66%). The third group included Fajri and Sindhri showed the infection level (23.33%). Similarly, in the next one were Langra, Saroli, Zafaran, Malda late and Early gold with (16.66%) infection. The two varieties Shan e Mustafa and Mahmood Khan showed (13.33%) infestation followed by Totapari, Ghulab e Khas and Chaunsa white with (11.66%) infection of the disease. Besides these, Armughan, Shan e Ali, Anmol, Yakta, Neelam, Anwar Ratole and Chaunsa Black showed (6.66%) infestation of the disease. The minimum disease incidence percentage was observed (3.33%) in Sensation and Almas. The varieties in eight groups were statistically similar. No variety was resistant to disease yet most of them showed a significant level of tolerance against the disease. Sensation and Almas presented low incidence value and they could be considered as resistant to the disease. The results of the disease severity index showed that there were two groups (A, AB) in which means were not statistically different. Maximum disease severity index was observed on Dusehri, Ratole No.12, Fajri, Sindhri, Chaunsa Samar Bahisht and Malda. Some varieties showed lowest disease severity index were Shan e Ali, Shan e Mustafa, Chaunsa White, Sensation, Ghulab e Khas and Armughan. The average number of fruit per tree significantly differed among all the varieties in five dissimilar groups in which the means were similar statistically ranging from 196 fruits (Almas) to 92 fruits (Armughan). The average (maximum) temperature during this experiment before the estimation of powdery mildew infection lingered around 25.6˚C to 31.2˚C whereas minimum temperature was recorded 11.2˚C to 20.0˚C. Precipitation was scarce during the assessment of disease while the last rainfall of 3.1 mm was recorded before the thirteen days of disease evaluation. On the whole, the atmospheric conditions were completely in favour of the disease by the fungus during the experiment as observed by [
The various mango cultivars showed varying response in relation to the infection of powdery mildew. There was no variety found to be resistant against the disease although they attained significant yield. It might be concluded that the presence or absence of symptoms caused by the powdery mildew had no such effect on the fruit yield of the mango cultivars.
Grateful acknowledgements are to Mr. Muhammad Tariq Malik, Assistant Plant Pathologist at Mango Research Institute, Multan, and the owners of Bhatti Mango Farm for facilitating us to conduct this work.