Effects of Sigatoka leaf spot (Mycosphaerella musicola Leach) on fruit yields, field ripening and greenlife of bananas in North Queensland

1990 ◽  
Vol 41 (4) ◽  
pp. 305-313 ◽  
Author(s):  
M.D. Ramsey ◽  
J.W. Daniells ◽  
V.J. Anderson
1963 ◽  
Vol 41 (10) ◽  
pp. 1481-1485 ◽  
Author(s):  
R. H. Stover

In addition to perithecia, spermagonia, and sporodochia of Mycosphaerella nmsicola Leach (Cercospora musac Zimm.), perithecia of M. minima Stahel, Leptosphaeria sp., Micronectridla sp. and Didymella sp. are present in banana leaf spots in Honduras. All of these fungi discharge ascospores from both surfaces of wet leaf spots. Discharges of M. musicola and Didymella are most abundant from June through December whereas ascospores of Micronectriella are abundant from January to June. Ascospores of M. minima and especially Leptosphaeria are abundant at all times. The two-celled ascospores of M. musicola, M. minima, and Didymella are readily identified by size, shape, and type of germination. M. musicola perithecia can be readily distinguished in non-sectioned lactophenol-cleared leaf tissue by the dark thick walls of the ostiole and periderm. M. minima and Micronectriella can produce ascospores in siugle-ascospore cultures. The latter also produces Fusarium macroconidia. Micronectriella sp. is present in young healthy leaves and is considered a banana leaf inhabitant. Perithecia of all species are more abundant in areas of mass leaf spot infection than in single, scattered spots.


1968 ◽  
Vol 46 (12) ◽  
pp. 1495-1505 ◽  
Author(s):  
R. H. Stover ◽  
J. D. Dickson

Oil spray reduced germination, germ tube growth, and appressoria formation by spores of Mycosphaerella musicola under field conditions for periods varying from 2 days to 2 weeks. Inhibition occurred only when spores were on the same leaf surface to which oil was applied. Appressoria formation and germ tube growth were reduced up to 33% and 25%, respectively. Conidia and ascospore production and dissemination were not adversely affected by oil spray. However, there were fewer sporodochia and perithecia in spots that were slow to develop as a result of oil spray. Oil application up to 2 weeks before or after infection increased the incubation period and the generation time, and reduced the number of spots. Oil is effective in retarding spot development when applied either before streaks appear or at the yellow streak stage of disease development. Oil, when applied during the incubation period or to yellow streaks, causes a variable amount of reduction in spotting and in only a minority of cases is disease development stopped completely. Therefore, leaf spot can build up on oil-sprayed plants when inoculum is abundant and weather favorable. The behavior of the pathogen on oil-sprayed susceptible banana plants is similar to that on partially resistant varieties.


1987 ◽  
Vol 27 (6) ◽  
pp. 919 ◽  
Author(s):  
MD Ramsey ◽  
LL Vawdrey ◽  
LG Schipke

Ten fungicides were evaluated in 3 experiments over 3 years for control of Sigatoka leaf spot, which is the major foliar disease of bananas in North Queensland. Benomyl(150 g a.i./ha), bitertanol(126 g a.i./ha), carbendazim (1 50 g a.i./ha), DPX H6573 (100 g a.i./ha), mancozeb (1760 g a.i./ha), nuarimol (60 g a.i./ha), propiconazole (50 g a.i./ha), RH3866 (250 g a d h a ) and triademenol (100 g a.i./ha), all applied with mineral oil (4 L/ha), and chlorothalonil (1300 g and 900 g a.i./ha) and propiconazole (100 g a.i./ ha), applied alone, all reduced the severity of leaf spot (P < 0.05). Bunch weights were increased by all fungicides compared with untreated plants during 1984 (P < 0.05). Effective disease control reduced the problem of premature fruit ripening from 100% of bunches in untreated plots to 0% in propiconazole (50 g a.i./ ha + oil and 100 g a.i./ha alone) treatments. Propiconazole was the most effective fungicide, applied either continuously (50 g a.i./ha + oil, or 100 g a.i./ha alone) or alternated (50 g a.i./ha + oil) with mancozeb + oil in a spray program. Propiconazole, bitertanol and nuarimol significantly reduced the size of Sigatoka lesions (P=0.05). An experimental fungicide DPXH6573 gave good disease control in 1985 and warrants further investigation.


EDIS ◽  
2017 ◽  
Vol 2017 (4) ◽  
Author(s):  
Keith W. Wynn ◽  
Nicholas S. Dufault ◽  
Rebecca L. Barocco

This ten-page fact sheet includes a summary of various fungicide spray programs for fungal disease control of early leaf spot, late leaf spot, and white mold/stem rot of peanut in 2012-2016 on-farm trials in Hamilton County. Written by K.W. Wynn, N.S. Dufault, and R.L. Barocco and published by the Plant Pathology Department.http://edis.ifas.ufl.edu/pp334


Sign in / Sign up

Export Citation Format

Share Document