Forecasting Model for leaf Spot of Banana by Md. Kamaruzzaman
DISCUSSION OF IMPORTANTDISCUSSION OF IMPORTANTFACTORS FOR FORECASTING ANDFACTORS FOR FORECASTING ANDCRITICAL WEATHER MODEL OF LEAFCRITICAL WEATHER MODEL OF LEAFSPOT OF BANANASPOT OF BANANA
ObjectivesObjectives TO KNOW THE FACTORS RESPONSIBLE FORFORECASTING TO KNOW THECRITICAL WEATHER MODEL OFLEAF SPOT OF BANANA
INTRODUCTION Black leaf streak, also known as Black Sigatoka, wasfirst recorded in 1964 from Fiji. This fungal disease ofbanana has since spread to most of the bananagrowing regions of the world and is regarded as one ofthe most important constraints on banana productionworldwide. The disease is particularly important wheregrowers cultivate monocrops of banana and cannotafford to use chemical fungicides for disease control.Black leaf streak can cause extensive defoliation. Yieldsare reduced, and fruit from affected plantations isprone to premature and uneven ripening. Becausebanana bunch weight is a function of the number ofhealthy leaves at flowering, it is critical to manage thecrop and the disease so that an acceptable quantityand quality of fruit is harvested
WHAT IS FORECASTING?WHAT IS FORECASTING? Giving information in advance about theepidemic of a disease and control measure.It isthe applied epidemiology. According to the Miller and O’Brien (1952)–“Forecasting involves all the activities inascertaining and notifying the growers of acommunity that ---- conditions are sufficiently favourable for certaindisease applicatiom of control measures will results ineconomic gain the amount of disease is enough to justify thecost of expenditure
CAUSAL ORGANISM OF LEAFSPOT OF BANANAMycosphaerella fijiensisCercospora musae
DISEASE SYMPTOMS The first symptom of LEAF SPOT OF BANANA is minute, chlorotic flecksthat appear on the undersurface of the third or fourth fully expanded leaf. Theflecks develop into narrow (1-2 X 10-20 mm) rusty brown streaks and oftenhave truncated ends and sides that are sharply limited by the leaf veins.During early stages, the streaks are visible only from the lower surfaces. On some cultivars, and on very young plants (suckers) the streaks are lessdefined and have diffuse margins The color of the lesions or streaks intensifies to dark red, brown, or black,sometimes with a purple tinge, and they become visible on the upper surfaces The streaks enlarge, becoming fusiform or elliptical, and darken to give thecharacteristic black streaking of the leaves. Conspicuous yellowing ofadjacent leaf tissue may also occur. The lesions dry to light gray with definite dark brown or black borders andoften have narrow, yellow transition zones between the borders and the greenleaf tissue. When disease severity is very high, large areas of the leaf may becomeblackened and water-soaked. As with yellow Sigatoka, the spots on juvenileleaves are oval or rounded and are often surrounded by a conspicuous yellowmargin. In extreme cases, all leaves can be destroyed before the bunch is mature, andthe bunch may fall from the plant.
CRITICAL WEATHER FOR LEAFSPOT OF BANANARELATIVE HUMIDITY 80-90%TEMPERATURE 10-16 DEGREECENTRIGRADECLOUDY WEATHER
MODEL FOR FORECASTINGA model is nothing but a sequentialhypothesis of what to do beforeepidemic .It is the simple and easyexpression of forecasting information.It can be expressed by graphically ordiagrammatically
A Critical weather model forA Critical weather model forleaf spot of bananaleaf spot of banana .. .FebruaryJanuaryDecemberNovemberOctoberSeptemberAugustJulyJuneMayAprilMarchTime offorecasting
Control measureVariety selection:The variety agnishar,sagor kola,amrito sagor etc.SPACING:Single-row or double row planting systems allowbest fungicide coverage for bananas and havesuperior air flow and reduced relative humiditylevels in the canopy.Weed control:Tall weeds (especially grasses) create highhumidity in the plant canopy, which favorsblack leaf streak disease.
CHEMICAL CONTROL Febuconazole, tebuconazole arereported to be the mosteffective. As systemicfungicides, the triazolefungicides provide the longestduration of disease mitigationafter application, but also posea risk for the development offungicide resistance if they areover used.
CONCLUTION:CONCLUTION: BY FORECASTING MESSAGE OURFARMERS BECOME ALERTABOUT THE DISEASE AND TAKEAPPROPRIATE MEASURES TOAVOID THAT DISEASE .THUSHIGH YIELD IS ACCEPTED.SOIT IS VERY LMPORTANT INAGRICULTURE.