Abstract
Experiments were conducted from 2014 to 2017. Field experiments were carried out in mango
orchards of selected farmers in three districts, viz., Dinajpur, Thakurgaon and Mymensingh. Pot
experiment was conducted in the Net-house of Department of Plant Pathology, Bangladesh
Agricultural University (BAU), Mymensingh. Laboratory experiments were carried out in the
Eco-friendly Plant Disease Management Laboratory, Department of Plant Pathology, BAU,
Mymensingh. In case of experiments at farmers level at Dinajpur, Thakurgaon and
Mymensingh, fungicide (Indofil M-45 @ 0.2%), insecticide (Confidor 70 WG @ 0.02%),
Phytohormone (2,4-D @ 12 ppm), irrigation and Urea (4%) were used. In case of field
experiment at BAU, Mymensingh, BAU-Biofungicide @ 3% was used along with all the
treatments that were used at farmers field of Dinajpur, Thakurgaon and Mymensingh. In case of
pot experiment, different plant extracts (extracts of Neem leaf, Mahagoni leaf, Mehendi leaf,
Allamanda leaf, Garlic clove and Basak leaf) @ 1:10 (w/v) and fungicides (Bavistin @ 0.1%, Tilt
250-EC @ 0.1%, Indofil M-45 @ 0.2%, Ridomil MZ @ 0.25%, Pipertox @ 0.5% and Thiovit @ 0.5
%) were used. Fungicides, plant extracts and chemicals were sprayed as solution/suspension to
the trees as per treatments. Spraying was done twice: once after full bloom stage and secondly
at marble stage of fruits. Irrigation was applied at 10 days interval starting from appearance of
bloom and continued up to marble stage. Out of the treatments used Indofil M-45 @ 0.2% plus
Confidor @ 0.02% resulted superior effect on management of flower and fruit dropping of
mango under field and Net-house conditions. Among the plant extracts, Mahagoni leaf extract
was found superior for management of flower and fruit dropping of mango over other plant
extracts. BAU-Biofungicide showed good results both in field and Net-house. Diseased samples
of dropped fruits, small-sized spotted fruits and diseased leaves were collected from the sites of
pot and field experiments and the fungi were isolated following tissue planting method. The
colony characters of the mycelial growth (size, shape, colour and compactness) of the pure
isolates were studied and the pathogens were identified as Colletotrichum gloeosporioides and
Botryodiplodia theobromae. Fungicides viz. Bavistin @ 0.1%, Tilt 250-EC@ 0.1%, Indofil M-45@
0.2%, Ridomil MZ@ 0.25%, Pipertox@ 0.05% and Thiovit@ 0.05%; BAU-Biofungicide, extracts of
plants viz. Neem leaf extract, Mahagoni leaf extract, Mehendi leaf extract, Allamanda leaf
extract, Garlic clove extract and Basak leaf extract @ 1:10 w/v; Urea @ 4% and phytohormones
viz. 2,4-D @ 12 ppm and NAA @ 40 ppm were tested under laboratory condition against the
growth of the isolated fungi. All the chemicals followed by BAU-Biofungicide and extracts of
Garlic and Allamanda proved better in inhibiting the mycelial growth of fungi. Based on the
findings of Field experiments, Pot experiment (Net-house) and Laboratory experiments, an
Integrated Crop Management (ICM) model has been developed for management of flower and
fruit dropping of mango. Under this ICM model, a mixture of Indofil M-45 @ 0.2% and Confidor
@ 0.02% (sprayed once after full bloom stage and secondly at marble stage of fruits) along with
irrigation (4 times at 10 days interval) starting from appearance of bloom and continued up to
the period of attaining marble stage of the fruits considered as best for management of flower
and fruit dropping of mango. This ICM model decreased disease severity of mango up to 45%
and increased the formation of healthy fruits up to 62.87% with the decrease of formation of
diseased fruits up to 71.80%. By application of this ICM model it has been found that dropping
of mango fruits reduced up to 70.48% with an increase of fruit yield of mango from 61.37 to
88.24%.