Stem end rot

Stem-end rot can be controlled by a combination of fungicide paste applied to the cut surface of the fruit and by observing sanitary practices with conveying equipment. Although epidemic upon occasions, this problem is now of little significance. 

Colombian stem-end rot, resulting from fungus invasion of cracked fruit stems and fruit peel in handling operations, however, is still of considerable importance. Some type of nonpoisonous fungicide dip is needed to control this problem. 

Fruit Decay. Finally in the field of diseases are the decays of fruit in transit. Much of the Brazilian fruit is exported, giving a long period from harvest to utilization and in Argentina a slow rail transport plus the use of uninsulated metal cars adds to the problem. Stem-end rot (Diaporthe citri Wolfe and Diplodia natalen-sis Pole-Evans) plus blue and green molds (Penicillium italicum, Wehmer, and P. digitatum, Sacc.) are rampant, and while the Dowicide A (sodium orthophenyl phe-nate)-Hexamine (hexamethylenetetramine) treatment worked out in Florida is satisfactory, import difficulties stand in the way of obtaining needed materials. 

GE Brown, HS Lee. Interactions of ethylene with citrus stem-end rot caused by Diplodia natalensis. Phytopathology 83 1204-1208, 1993. 

Exposure of citrus fruits to ethylene has been shown to increase the incidence of stem-end rot caused primarily by D natalensis (113, 124, 125, 126, 127). Higher than recommended ethylene concentrations (75, 106, 116, 128, 129) and temperature (116) and an increase in degreening duration (116, 125) caused significant increases in stem-end rot. Anthracnose, caused by . gloeosporioides, is a serious disease of specialty citrus hybrids such as Robinson, Lee, Nova, and Page (130, 131), when fruit are exposed to ethylene. Incidence was related directly to length of degreening (130), ethylene concentration (132,... 

This procedure requires 2 to 3 weeks during which time juice yield and citric acid increase (153). In an effort to speed up the process, ethephon or standard degreening practices have been used but these usually enhance decay, particularly stem-end rot (126, 148, 150, 153). Degreening was achieved with standard degreemng practices if mature fruit were treated with an effec-... 

Control of stem-end rots caused by A. citri, D. natalensis, and P. citri with postharvest applications of the growth regu-lators 2, 4-D and, occasionally, 2,4,5-T is attributed to preservation of the green button and prevention of abscission (106,... 

The total number of berries with fruit rot symptoms and the number of berries with symptoms of anthracnose or stem end rot from the April 24 harvest time were significantly lower from plots treated with the fungicides Switch, Cabrio , CaptEvate , and Pristine than from those receiving no fungicide treatment (Table 2). The most prevalent diseases in the Louisiana field study were anthracnose caused... 

Number of fruit with anthracnose fruit rot symptomn (Colletotrichum acutatum) or Stem-End Rot (Gnomonia comari). 

Improved fruit retention increase in fruit weight reduced incidence of stem end rot and spotted fruits reduced occurrence of spongy tissue good shine and skin gloss. 

It is best if the branch is cut back to just below a node since nodes are the places from which new roots are most likely to develop. While it is not necessary to cut make the cut here, doing so has the advantage that there will be no stem material dangling in the water below the node. This is important as the cut stem end is more likely to start to rot than is a node. 

By keeping ethylene concentrations to less than 0.8 ul/1 of air, stem-end decay caused by a species of Fusarium, green mold, loss of orange flavor, and development of off-flavors were minimized. Other volatiles present with and without the ethylene absorber apparently had no effect on quality. Ethylene, produced in copious quantities by rots, enhances respiration and senescence of healthy fruit within the storage facility (281). The importance of ethylene removal has been illustrated also in recent storage studies of lemons in Australia (282, 283, 284, 285). 

Fungicide Total Rots Anthracnose2 Stem end rot2 Plants Dead (%)3 Foliar disease4 ... 

Potatoes with a black, rotted ring at stem ends. Cause Bacterial ring rot. Tubers have a soft, light brown ring in the flesh near the skin. See Leaves discolored and puckered or curled on page 188 for controls. 

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