Fumigation of stonefruit with acetic acid to control postharvest decay

Fumigation of stonefruit with acetic acid to control postharvest decay Peter L. Sholberg* Agriculture

and Alan P. Gaunce

and Agri-Food

Canada, Research Centre, Summerland,

British Columbia,

Canada VOH 1ZO

Acetic

acid was an effective

apricots, prevented

and cherries. by as little

Decay

postharvest

fumigant

by Monilinia

fructicola

Glohaven

the phytotoxicity

of acetic acid increased injury;

peaches treated

harvest then fumigated

brown

rot (12.5%)

spores on peaches,

the streaks darkened

on Harbrite

Harbrite

indicated

in the orchard with captan at 5% bloom,

before

due to Akrnaria

fungal

and Rhizopus stolonifer

as 1.4 or 2.7 mg I-’ acetic acid, respectively.

2.7 mg I-’ acetic acid were slightly injured, concentrations

to destroy

peaches fumigated

by light brown streaks.

spp., was reduced

with captan alone (25.0%). from

38.9

to 10.0%

with

Higher

and became much more pronounced. full bloom,

ripening fruit, and 2 days

with 2.7 mg I-’ acetic acid after harvest had significantly

than fruit treated

nectarines, peaches was

Decay

by fumigation

of Lambert with

less postharvest

cherries,

2.7 mg I-’

primarily

acetic acid.

Unfortunately, small pits developed in the fruit surface during storage at 1°C. Brown rot (M. fructicola) of Tilton apricots was reduced from 100 to 25% by fumigation with 2.0 mg I-’ acetic acid without signs of scverc phytotoxicity.

Keywords:

Monilinia

Crown

copyright

fructicola;

@ 1996 Published

Rhizopus

stolonifer;

by Elsevier brown

rot;

Science Ltd peaches;

nectarines;

apricots;

cherries

There is a serious need for alternatives to synthetic fungicides to control postharvest diseases of stonefruit. Dichloran is presently the only fungicide registered for postharvest use on stonefruit in Canada. Combined with benomyl or captan, it is very effective in preventing postharvest decay of stonefruit caused by Monifinia fructicola (Wint.) Honey or Rhizopus stolonifer (Ehrenb.: Fr.) Vuill. (Ogawa and English, 1991). When used alone it has limited effectiveness against M. fructicola, which is one of the major postharvest pathogens of apricots, peaches, nectarines, and cherries in British Columbia (Meheriuk and McPhee, 1984). Growers must depend on preharvest sprays of benomyl, captan, or iprodione for control to extend into the postharvest period. Application immediately prior to harvest is inefficient because stonefruit trees are heavily enveloped with foliage resulting in poor spray coverage. Furthermore, resistance by M. fructicolu to benomyl and iprodione has been documented around the world (Ogawa, Manji, Adaskaveg, and Michailides 1988; Gouot, 1988) and because synthetic fungicides leave residue which have been connected to risks of carcinogenicity and teratogenicity (Archibald and Winter, 1990) regulatory authorities and some consumers are concerned about their use. Natural volatiles are promising alternatives to synthetic fungicides for postharvest decay control of

*Author to whom correspondence should be Summerland Research Centre contribution no. 961.

addressed.

fruits and vegetables (Wilson and Wisniewski, 1989). Wilson, Franklin, and Otto (1987) reported that three compounds (benzaldehyde, methyl salicylate, and ethyl benzoate) completely inhibited the growth of M. ,fructicola and Botrytis cinerea Fr. at 370 ul I-‘. However, none of the 16 volatiles applied at 1250 ul 1-l to spores of M. fructicola completely prevented spore germination, although four volatiles reduced germination to less than 1%. Decay of raspberries and strawberries inoculated with B. cinerea and apples inoculated with Penicillium expansum were controlled by fumigation with acetaldehyde vapour (Stadelbacher and Aharoni, 1971; Prasad and Stadelbacher, 1973; Stadelbacher and Prasad, 1974). In a more recent study, Mattheis and Roberts (1993) reported that acetaldehyde and propanal fumigation of Bing cherries effectively controlled decay caused by P. expansum but also induced excessive stem browning. It is surprising that none of these natural volatiles have been adopted for commercial use. Relatively high cost, the threat of phytotoxicity. the possibility of explosion, lack of published, large-scale semi-commercial trials and regulatory requirements have possibly discouraged their use. Acetic acid, a stable compound manufactured in large volume for numerous industrial processes (Lodal, 1993), could offer promise in the vapour phase for controlling postharvest pathogens. It was screened as a fumigant against conidia of M. fructicola on peach fruit and found to reduce the germination to zero; however, research on its use was not pursued because glacial acetic acid at the vapour concentration used in this study

Crop

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1996 Volume

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Fumigation of stonefruit with acetic acid: P.L. Sholberg and A.P. Gaunce blackened the fruit in a few minutes (Roberts and Dunegan, 1932). Recently, acetic acid vapour at relatively low concentrations in air prevented germination of conidia of B. cinerea and P. expansum and prevented infection of apples without injury to the fruit (Sholberg and Gaunce, 1995). P. expansum conidia on apple were completely prevented from infecting injured apple tissue when fumigated for 60 min with 4.0 mg 1-l (0.15%) compared to 2% for 60 min with acetaldehyde on P. expansum (Stadelbacher and Prasad, 1974). Therefore, acetic acid vapour was about 13 times more active than acetaldehyde for the control of P. expansum conidia. The object of this study was to determine if fumigation with acetic acid would prevent the germination of M. fructicola and R. stolonifer spores on peaches and prevent postharvest brown rot from occurring on stonefruit without excessive injury to the fruit.

Materials

and methods

Fruit Stonefruit were harvested at commercial maturity from the research orchard of Agriculture and Agri-Food Canada, Summerland, British Columbia. Peaches used for testing control of pathogen infection were stored at 1°C until required. Immediately prior to use the peaches were surface-sterilized (0.05% sodium hypochlorite for 1 min), rinsed for 1 min in sterile distilled water, and allowed to dry for at least 1 h at 20°C. Fruit used in experiments simulating commercial conditions employed several fruit per replicate that were not surface-sterilized after storage at 1°C.

lnoculum Fruit were inoculated with cultures of fungi obtained from infected stonefruit from the same orchard during the season in which fruit were obtained in order to ensure pathogenicity. Cultures used were M. fructicola isolated from an infected nectarine and R. stolonifer isolated from an infected peach. The isolates were cultured on potato dextrose agar (PDA) for l-2 weeks at 2@23”C. Spores were harvested by washing a sporulating culture with 5-10 ml sterile distilled water into a screw cap test-tube. Contents were thoroughly mixed prior to counting with a haemacytometer. Peach fruit were inoculated in a laminar flow hood with three 20 ~1drops of spore suspension arranged in a triangular pattern (Figure I). The concentration of the drops for M. fructicola and R. stolonifer was 1.2-8.0 X lo4 and 1.2-3.5 X 10’ spores ml-‘, respectively. Prior to placing the drops of spore suspension on the fruit surface, the area where the drops were to be placed was wiped with a 95% ethanol solution. Each drop was placed within a 5 mm diameter circle inscribed with a marking pen. The drops were allowed to dry for at least 1 h on the peach surface until all signs of liquid had disappeared. Replicates of apricots and cherries were inoculated by dipping in a spore suspension of 0.5-I .O X lo4 conidia ml-’ of M. fructicola.

Fumigation Fruit were fumigated with reagent grade acetic acid in as many as four 12.7 I chambers made from 11 kg capacity tin cans (Fisher Scientific, Vancouver, Canada) fitted with a 0.6 A, 115 V circulation fan attached to

Figure 1. Peaches displayed symptoms of phytotoxicitywhen fumigated with acetic acid concentrations higher than 2.0 mg 1-l. Typical symptoms of phytotoxicity are shown on this peach that had been fumigated with 4.0 mg I-’ acetic acid

662

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Protection

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Fumigation of stonefruit with acetic acid: P.L. Sholberg and A.P. Gaunce

the lid. The fumigation procedure and details on construction of the chambers are described elsewhere (Sholberg and Gaunce, 1995). Prior to fumigation the circulation fan was turned on and reagent grade glacial acetic acid was injected via microsyringe onto a filter paper wick in the chamber where it evaporated in 14 min depending on volume applied. Stonefruit fumigations were conducted at 5.0 ? 0.2”C and 95.0 + 5.0% relative humidity within an environmentally controlled room (Conviron Co., Winnipeg, Canada). Fruit were equilibrated to temperature and humidity for at least 3 h before fumigation within the room. Fruit were fumigated for 1 h, then each replicate was removed from the chamber and placed in a laminar flow hood for 20-30 min to aerate. After aeration, peaches were aseptically injured with a glass rod (2 mm diameter) within the inscribed circles to a depth of approximately 5 mm and incubated at 20.0 f 0.2”C for at least 3 days. Apricots and cherries which had been dipped in a spore suspension of M. fructicola were injured at three and four equidistant locations, respectively, and incubated at 20.0 k 02°C for 4 days. Care was taken to avoid cross-contamination between treatments by always injuring the highest concentration fruit first and flaming the glass rod between treatments. Larger samples of apricots, cherries, and peaches were also fumigated. Tilton apricots were injured at three locations as described above after fumigation with 2.7 mg I-’ acetic acid and stored at 5.0 * 0.2”C for 21 days. Lambert cherries were separated into four replicates of about 250 cherries each treated with 2.7 mg I-’ acetic acid, and immediately stored at 1.0 + 0.2”C for 45 days in poly bags. Three single tree replicates of Glohaven peaches were sprayed until runoff with captan (100 ml-‘) at 5% bloom,

pg ml-‘)

and iprodione

(25 vg

full bloom, ripening fruit and 2 days before harvest. Four replicates of 10 fruit each of untreated or captan and iprodione treated fruit were fumigated with 2.7 mg I-’ acetic acid and stored at 20.0 & 0.2”C for 10 days at high relative humidity provided by covering fruit with cheesecloth moistened with water. Evaluation fruit were inspected for signs of phytotoxicity such as browning, streaking or pitting in addition to decay. Inoculated peaches were evaluated for decay by measuring the diameter of each lesion with a ruler in two directions and taking the average of three lesions for each single fruit replicate. Injured apricots and cherries inoculated with M. fructicofa were evaluated by counting the number of fruit in each replicate infected by M. fructicofa as indicated by sporulation on the fruit surface. Apricots stored for 21 days at 5.o”C were evaluated by counting the number of fruit with infection caused by Monilinia spp., Rhizopus spp. or other postharvest pathogens. Lambert cherries were evaluated for mold infection caused by postharvest pathogens such as Afternaria spp. Standard deviations were calculated for each treatment. Soluble solids and titratable acidity were determined for fumigated and unfumigated cherries after storage. Glohaven peaches were evaluated for infection by M. fructicofa by counting the number of fruit in each replicate that were Fumigated

infected. Analysis of variance was carried out on the arcsine transformed data using the General Linear Models Procedure (SAS Institute, Cary, NC).

Results and discussion

One nectarine and three peach cultivars inoculated with conidia of M. fructicola did not decay when fumigated with 2.00 mg I-’ acetic acid (Table I). Decay in Harbrite peaches was prevented by as little as 1.35 mg I-’ acetic acid. Wilson et al. (1987) considered benzaldehyde the most active fumigant for inhibiting conidia of M. fructicofa at a concentration of 12.5 ~1 I-‘. Apparently, acetic acid is much more active than benzaldehyde when used as a fumigant against M. fructicofa. Acetic acid vapour concentrations of 2.70 mg I-’ and higher caused injury to both peaches and nectarines (Figure I); brown streaks on peaches and reddish brown streaks on nectarines. These brown streaks were consistent with what has been reported as skin discoloration (Snowdon, 1990). The effect of low pH on peach skin discoloration has been hypothesized by Denny, Coston, and Ballard (1986) as follows: at low pH values, cations are ionized and freely soluble in water. As water enters the peach through damaged areas, these ions also enter. These ions could bind with anthrocyanins or more likely tannic substances (Arakawa and Ogawa, 1994), and result in dark coloration. This suggests that acetic acid fumigation at concentrations higher than 2.0 mg I-’ might be accomplished without phytotoxicity by drying the fruit and preventing the accumulation of water droplets until all residual acetic acid has dissipated. R. stolonifer was more difficult to control that M. fructicola on Harbrite peaches, at least 2.00 mg I-’ (Table 2 and Figure 2) was needed. Aharoni and Stadelbacher (1973) found that R. stofonifer spores were more resistant than M. fructicola to acetaldehyde and required 0.75% compared to 0.25%. respectively, to kill all the spores after fumigation for 90 min. Acetic acid vapour was much more active than acetaldehyde vapour. For example, 2.00% (39 mg I-‘) acetaldehyde vapour was required to kill 50% of a suspension of R. stolonifer spores compared to 0.075% (2.0 mg I-‘) acetic acid vapour required to kill 100% of the spores on peach surfaces during a 30 min fumigation.

Table 1. Effect of acetic acid fumigation of Monilinia fructicola on peaches and nectarines

on

conidia

Lesion diameter (mm)~’ Dosage (ms

1 ‘1

0.00 1.35

Unknown peach

Harbrite peach

Vee peach

Unknown nectarine

28.4 t 2.4 _

48.0 + 5.X 0.0 + 0.0

14.6 + 6.7 _

16.2 t 6.2

0.0 + 0.0 0.0 + 0.0 0.0 + 0.0 -

0.0 & I).0 0.0 + 0.0 _

2.00 2.70” 4.00’ 5.30’ “Four

0.0 0.0 0.0 0.0 single

conidial a, 20.0 ‘Severe

replicatesinoculated

fruit

suspension + 0.2-C

hModerate

?z 0.0 + 0.0 -t 0.0 f 0.0

(1.2-8.0

with

X IO c.f.u.

three

ml

drops

0.0 0.0 0.0 0.u

(20 ~1) of M.

‘) per treatment.

Fruit

t 0.0 ?I 0.0 ?I 0.0 + 0.0

frucficola was stored

for 3 days

phytotoxicity

phytotoxicity

indicated indicated

by brown

by brown

streaks

discoloratwn

on the fruit of the fruit

surface surface

Crop Protection 1996 Volume 15 Number 8

683

Fumigation

of stonefruit

with acetic acid: P.L. Sholberg

and A.P. Gaunce

Figure 2. Control of Rhizopus rot on Harbrite peaches. The peach at the top of the photograph was not fumigated. The peach on the lower left was fumigated with 1.35 mg I-’ and the one on lower right was fumigated with 2.00 mg I-’ acetic acid

Table 2. Effect of acetic acid fumigation on spores of Rhizopus

stoloniferon peaches

Lesion

diameter

Table 3. Effect of acetic acid fumigation on apricots and cherries dipped in a Monilinia fructicolaconidial suspension (0.5-1.0 X lo4 c.f.u. ml-‘)

(mm)” Percent

Dosage Harbrite

(mg 1-l)

#

1

Harbrite

#2

after

Dosage 0.00 1.35 2.00 2.70b 4.00h 5.30’

27.3 + 6.7 -

40.0 40.0 0.0 0.0 0.0

1.8 + 3.6 1.4 + 2.8 0.0 + 0.0

+ f f f +

0.0 0.0 0.0 0.0 0.0

40.0 t 0.0 5.0 4.3 0.0 0.0

+ * + ?I

6.8 5.0 0.0 0.0

single

fruit

spore suspension 20.0

+ O.PC

hModerate ‘Severe

replicates (1.2-3.5

inoculated

with

X 10J c.f.u.

ml-‘)

three

drops

R. stobnifer

(20 ~1) of

per treatment.

Fruit

was stored

at

phytotoxicity

indicated indicated

by brown

by surface

streaks

browning

on fruit of fruit

replicats

surface

of four

apricots

of 25 cherries of 25 cherries

experienced

as reddish-brown

100.0

per treatment

per treatment

stored stored

each per treatment

over

the fruit

46.0 f 2.8 14.6 f 3.0 2.1 * 3.0

0.0

91.0 f 6.0 23.0 + 2.0

severe phytotoxicity

streaks

f

Sylvia cherry’

stored

at 4.00

at 20 + 0.2”C

at 20 + 0.2”C at 20 k 0.2”C

for 4 days for 4 days for 4 days

mg 1.’ acetic acid expressed

surface

surface

Apricots and cherries which had been dipped in conidial suspensions of M. fructicola, fumigated, and mechanically injured developed less brown rot than unfumigated fruit (Table 3). Acetic acid applied at 2.00 mg I-’ reduced the number of fruit infected by M. fructicola on both apricots and Sylvia cherries. Tilton apricots developed reddish-brown streaks on the fruit surface during storage when fumigated with more than 2.00 mg I-’ acetic acid. Sweetheart cherries stored for 21 days at 5.O”C after fumigation with 5.3 mg 1-l acetic acid had half as much decay as the control fruit (Table 4). Decay was primarily due to infection by Alternaria spp. among controls and Penicillium spp. among treated cherries. The infection of Lambert cherries by Alternaria spp. w.as reduced from 39 to 10% by

664 0op:Protection

Two

replicates

‘Apricots

for 3 days

phytotoxicity

replicates

hFour

injuring

Unknown cherryh

100.0 f 0.0 25.0 ?I 0.0 8.3 f 14.4"

0.0 2.0 4.0 “Three

“Four

Tilton apricoti*

(mg 1-l)

with M. fructicola

fruit infected

Parson’s seedling

1996 Volume 15 Nuri-&er 8

Table 4. Effect of acetic acid fumigation on the decay of stored l-amber-t and Sweetheart cherries Percent

infected

fruit

Dosage Lambert”

(mg 1-l)

38.9 f 5.6

0.0 2.0 2.7 5.3 “Four stored hTwo

Sweetheart’ 48.4 39.2 38.3 24.2

10.0 + 4.7C

replicates

of approx.

250 naturally

contaminated

cherries

+ f f +

0.0 8.4 7.1 2.3

per treatment

for 45 days at 1°C replicates

of 30 naturally

contaminated

days at 1°C ‘Depressions

on the fruit

surface

fruit

per treatment

stored

for 21

Fumigation fumigation with 2.70 mg I-’ acetic acid. However, small pits approximately 2 mm in diameter developed over the surface of the fumigated fruit during storage. Surface pitting of cherries has been described as a storage disorder which produces one or more irregular depressions in the surface of the fruit (Porritt, Lopatecki, and Meheriuk, 1971). The pitting observed during this study was different in that each cherry was covered with many small depressions rather than one or two large depressions. Pits occurred on Lambert cherries but not on Sweetheart cherries. The soluble solids (20.8 i 0.3 vs 20.8 i 1.0) or titratable acid (726.0 + 24.7 vs 761.5 + 69.8) contents of fumigated Lambert cherries were not significantly different from unfumigated fruit. Informal tasting of the fruit did not indicate any difference in taste of treated and healthy fruit. Thus, preliminary indications are that acetic acid fumigation does not have any deleterious effect on the internal quality of the cherry fruit. Pitting of Lambert cherries may be eliminated by using lower concentrations of acetic acid. Commercially-grown peaches are usually treated with captan or iprodione in British Columbia before harvest to control fruit brown rot (Anon., 1993). Peaches that were treated before harvest with these fungicides and fumigated with 2.7 mg I-’ acetic acid had significantly less M. frucicola infections than unfumigated fruit (Table 5). A possible explanation is that fumigation with acetic acid is only effective on surface-borne spores and has no effect on quiescent or latent infections. These infections occur in fruit at various stages of immaturity, and decay is delayed until the fruit matures and ripens (Jenkins and Reinganum, 1965). Smilanick et al. (1993) screened biocontrol agents for M. fructicola on peaches and nectarines, and found that infections characteristic of commerciallygrown fruit were not accurately simulated by artificial inoculation methods probably because of latent infections. These preliminary studies with several stonefruit varieties has shown that fumigation with acetic acid has potential as a postharvest decay control if latent infections are controlled. It was effective against M. fructicola, R. stolonifer and naturally occurring Afternaria spp. Acetic acid could be used at higher dosages if visual appearance of the fruit was not a consideration, for example, if the fruit are used in processed products such as purees, juices, or canned. Further research is required to determine if fumigation

of stonefruit

with acetic acid: P.L. Sholberg and A.P. Gaunce

with acetic acid effects fruit quality and if it could provide enough decay control to be used commercially. Acknowledgements We thank Karen Bedford and Paula Haag for technical assistance over the course of the study. We also thank Dr Mike Meheriuk and Darrell-Lee McKenzie for a preliminary assessment of the effect of acetic acid fumigation on cherry fruit quality. References Aharoni,

Y.

and Stadelbacher,

G. J. (1973)

aldehyde vapors to postharvest Phytopathology 63. W-545 Arakawd,

0.

and Ogawa,

black discoloration 29. 18Y-ISO

pathogens

The

of fruits

toxicity

of

acet-

and vegetables.

(lYY4) Histological studies on the fruit skin exposed to iron. HortScience

J. M.

of peach

S. 0. and Winter, C. K. (lo(O) Pesticides in our food. Assessing the risks. In: Chemicals in the Human Food Chain (Ed, by C. K. Winter. J. N. Seiber and C. F. Nuckton) pp. l-50, Van Nostrand Reinhold. New York

Archibald,

Denny,

E. G.,

Coston,

D. C. and Ballard,

R. E (1Y86)

Peach

skin

J. Am. Sot. Hort. Sci. 111, 54Y-553

discoloration.

J.-M. (1088) Characteristics and populrtion dynamics of Rotrytis cinerea and other pathogens resistant to dicarboximides. In: Fungicide Resistance in North America (Ed. by C. J. Delp) pp. 53-55. APS Press. St. Paul

Gouot,

P. T. and Reinganum, C. (1965) The occurrence of a quiescent infection of stone fruits caused by Sclerotinia fructicola (Wint) Rehm. Aust. J. Agric. Res. 16. 131-130

Jenkins,

P. N. (lYY3) Production economics. In: Acetic Acid and Its Derivatives (Ed. by V. H. Agreda and J. R. Zoellcr) pp. 61-69. Marcel Dekker. Inc., New York

Lodal,

Mattheis,

J. P. and Roberts,

R. G. (IYY3) Fumigation

of sweet cherry

(Prunus avium ‘Bing’) fruit with low molecular weight posthavest decay control. Plant Dis. 77, 81&X14

aldehydes

for

M. and McPhee, W. J. (I 984) Postharvesr Handling of Pome Fruits, Soft Fruits, and Grapes. Agriculture Canada Publication No. 1768E. Meheriuk,

J. M. and English, H. (1YYl) Diseases of Temperate Zone Tree Fruit and Nut Crops. University of California, Division of Agriculture and Natural Resources, Oakland. CA. Publication 3345

Ogawa,

Ogawa, J. M., Manji, B. T., Adaskaveg, J. E. and Michailides, T. J. (1988) Population dynamics of benzimidazole-resistant Monilinia

species on stone fruit trees in California. In: Fungicide Resistance in North America (Ed. by C. J. Delp) pp. 3&3Y. APS Press, St. Paul Porritt, S. W., Lopatecki, I,. E. and Meheriuk, M. (1971) Surface pitting - A storage disorder of sweet cherries. Can. J. Plunt Sci. 51. 409-4 I4 Prasad, K. and Stadelbacher, G. J. (1973) Control of postharvest decay of fresh raspberries by acetaldehyde vapor. Plant Dis. Reptr.

Table 5. Effect of acetic acid fumigation on percentage brown rot of peaches after preharvest treatment with captan or iprodione Preharvest Dosage (mg ml -‘) 0.0 2.7

None 35.0 b” 55.0 a

treatment”

25.0 a 12.5 b

Roberts,

J. W.

Technical Bulletin DC, 5Y pp

and

Dunegan,

J. C.

No. 328, US Dept.

(lY32) Peach of Agriculture,

brown rot. Washington,

Sholberg, P. L. and Gaunce, A. P. (1995) Fumigation of fruit with acetic acid to prevent postharvest decay. HortScience 30, 1271-1275 J. L., Denis-Arrue, R., Bosch, J. R., Gonzales, A. R., Henson, D. and Janisiewicz, W. J. (1993) Control of postharvest brown rot of nectarines and peaches by Pseudomonas species. Crop Prot. 12, 513-520

Smilanick,

Iprodione

Captan

57, 795-707

20.0 a 10.0 b

A. L. (1990) A Color Atlas of Post-Harvest Diseases and Disorders of Fruits and Vegetables. CRC Press, Inc., Boca Raton, FI, 302 pp

Snowdon, “Four replicates of IO naturally contaminated fruit 20.0 IL 0.2X for 10 days hMeans in the same column followed by different different at the 0.05 level according to the F-test.

per treatment letters

stored

are significantly

at

Stadelbacher,

G. J. and Aharoni,

Crop

Protection

1996

Y. (1071)

Acetaldehyde

Volume

15 Number

vapor

8

685

Fumigation of stonefruit with acetic acid: P.L. Sholberg and A.P. Gaunce treatment

to control

HortScience

Stadelbacher,

postharvest

C. L., Franklin,

inhibitory to 316-319

686

(Abstr.)

G. J. and Prasad, K. (1974) Postharvest decay control

of apple by acetaldehyde vapor. Wilson,

decay in strawberries

6, 280

Monilinia

J. Am.

Sot.

Hort.

Sci. 99. 364-368

J. D. and Otto, B. E. (1987) Fruit volatiles fructicola

and

Botrytis

C. L. and Wisniewski, M. E. (IYW) Biological control of postharvest diseases of fruits and vegetables: an emerging technology. Annu. Rev. Phytopathol. 27. 425-441 Wilson,

cinerea.

Plant

Crop Protections 19% Vofurne~5 Number 8

Dis. 71,

Received 8 December 1995 Revised 6 March 1996 Accepted I1 March 1’3%