Vapors of several common vinegars containing 4.2% to 6.0% (= 2.5 to 3.6 mol·L-1) acetic acid effectively prevented conidia of brown rot [Monilinia fructicola (G. Wint.) Honey], gray mold (Botrytis cinerea Pers.:Fr.), and blue mold (Penicillium expansum Link) from germinating and causing decay of stone fruit (Prunus sp.), strawberries (Fragaria ×ananassa Duchesne), and apples (Malus ×domestica Borkh.), respectively. Fruit were fumigated in 12.7-L sealed containers in which vinegar was dripped on to filter paper wicks or vaporized by heating from an aluminum receptacle. Vapor from 1.0 mL of red wine vinegar (6.0% acetic acid) reduced decay by M. fructicola on `Sundrop' apricots (Prunus armeniaca L.) from 100% to 0%. Similarly, vapor from 1.0 mL of white vinegar (5.0% acetic acid) reduced decay in strawberries by B. cinerea from 50% to 1.4%. Eight different vinegars, ranging from 4.2% to 6.0% acetic acid, of which 0.5 mL of each vinegar was heat-vaporized, reduced decay by P. expansum to 1% or less in `Jonagold' apples. The volume of heat-vaporized white vinegar (5.0% acetic acid) necessary to reduce decay by P. expansum on `Jonagold' apples to zero was 36.6 μL·L-1 of air. Increasing the number of conidia on the apple surface reduced the effectiveness of vinegar vapor. The number of lesions caused by P. expansum on `McIntosh' apple decreased exponentially with increasing time of fumigation, approaching zero after about 6 hours. These results suggest that vinegar vapor could be an effective alternative to liquid biocides such as sodium hypochlorite for sterilization of surfaces contaminated by conidia of fungal pathogens.
Peter Sholberg, Paula Haag, Rod Hocking, and Karen Bedford
D. Boonyakiat, R. A. Spotts, and D. G. Richardson
Chlorogenic acid and arbutin reduced spore germination of Penicillium expansum Lk. ex Thom, and mycelial growth of Mucor piriformis Fischer. Arbutin decreased growth of Botrytis cinerea Per ex Fr. However, chlorogenic acid increased both germination and growth of B. cinerea.
Peter L. Sholberg and Paul Randall
control of B. cinerea . Subsequent studies showed that when ‘Crimson Seedless’ table grapes were fumigated with (E) -2-hexenal, gray mold was suppressed but not completely controlled ( Archbold et al., 1999 ). Penicillium expansum Link causes the
David Sugar, Timothy L. Righetti, Enrique E. Sanchez, and Habib Khemira
Management of pear (Pyrus communis L.) trees for low N and high Ca content in the fruit reduced the severity of postharvest fungal decay. Application of N fertilizer 3 weeks before harvest supplied N for tree reserves and for flowers the following spring without increasing fruit N. Calcium chloride sprays during the growing season increased fruit Ca content. Nitrogen and Ca management appear to be additive factors in decay reduction. Fruit density and position in the tree canopy influenced their response to N fertilization. Nitrogen: Ca ratios were lower in fruit from the east quadrant and bottom third of trees and from the distal portion of branches. High fruit density was associated with low N: Ca ratios. Nutritional manipulations appear to be compatible with other methods of postharvest decay control.
Ibrahim I. Tahir, Eva Johansson, and Marie E. Olsson
distribution organizations. Infections by Pezicula malicorticis (bull's eye rot), Penicillium expansum (blue mould), and Colletotrichum gloeosporioides (bitter rot) are the main causes of decay during apple storage in Sweden ( Tahir, 2006 ). Because pre
G. D. Blanpied and Apithai Purnasiri
2-(4-Thiazolyl) benzimidazole (thiabendazole or TBZ) applied as a postharvest treatment (1000-2000 ppm) significantly reduced decay of apples: intact (not skin punctured); skin punctured before or after TBZ treatment; mechanically harvested; waxed after TBZ treatment. TBZ was active against Penicillium expansum, Botrytis sp., but not Alternaria sp. New skin punctures were more susceptible to infection than old punctures.
C. A. Cargo and D. H. Dewey
Postharvest treatment with thiabendazole (TBZ) or benomyl reduced the incidence of soft rot or blue mold disease caused by Penicillium expansum Thorn in ‘Mcintosh’ apple fruits. Both materials were significantly effective during cold storage or simulated marketing tests in which the apples were artificially punctured and then dipped in solutions containing rot inoculum and the chemical. All concentrations tested, 250, 500 and 1000 ppm TBZ and 75, 140, and 300 ppm benomyl, yielded rot control without affecting the respiratory activity of the apples.
Ruth Ben-Arie and Sylvia Guelfat-Reich
Two orchard sprays with 800 ppm methyl l-(butylcarbamoyl)-2-benzimidazole-carbamate (benomyl) or three orchard sprays with 300 ppm 2-(4-thiazolyl) benzimidazole (thiabendazole or TBZ) achieved significant control of storage decay of ‘Spadona’ pears (Pyrus communis L.). Almost complete control of storage decay required postharvest dip-treatments of 1000 ppm benomyl or 500 ppm TBZ. Penicillium expansum and Botrytis cinerea (Pers. ex Fr.) were inhibited by these treatments but Alternaria tenuis (Nees ex Cda.) was unaffected and its incidence increased during storage, possibly due to control of the other organisms. These benzimidazole treatments tended to increase the incidence of internal breakdown of treated pears during prolonged regular cold storage.
William S. Conway and C.E. Sams
‘Delicious’ apples (Malus domestica Borkh.) were pressure-infiltrated (68.95 kPa) above atmospheric at harvest with CaCl2, MgCl2, or SrCl2. After 5 months in storage at 0°C, the fruit were removed, wound-inoculated with a conidial suspension of Penicillium expansum, and kept for 7 days at 20°. Fruit then were rated for decay severity, ethylene production, respiration, firmness, and injury, and analyzed for the concentration of the appropriate cation. Calcium was the optimum cation for reducing decay, maintaining fruit firmness, and suppressing ethylene production. Cation treatments had little effect on respiration, and Mg was the only cation that caused distinctive injury to the fruit surface.
Harold E. Moline and James C. Locke
The antifungal properties of a hydrophobic neem (Azadirachta indica A. Juss.) seed extract (clarified neem oil) were tested against three postharvest apple (Malus domestica Borkh.) pathogens—Botrytis cinerea (pers.) ex Fr. (gray mold), Penicillium expansum Thom. (blue mold rot), and Glomerella cingulata (Ston.) Spauld. & Schrenk. (bitter rot). The antifungal activity of neem seed oil also was compared to that of CaCl2. A 2% aqueous emulsion of the clarified neem seed oil was moderately fungicidal to B. cinerea and G. cingulata in inoculated fruit, but bad little activity against P. expansum. Ethylene production was reduced 80% in fruit dipped in 2% neem seed oil compared to wounded, inoculated controls. Neem seed oil was as effective an antifungal agent as CaCl2, but the effects of the two combined were not additive.