Management strategies for control of Penicillium decay in lemon packinghouses: economic benefits

doi:10.1016/0261-2194(86)90035-9

Crop Protection

Volume 5, Issue 1, February 1986, Pages 26-32

https://doi.org/10.1016/0261-2194(86)90035-9 Get rights and content

Abstract

Continued use of fungicides to control postharvest pathogens is becoming not only expensive, but less effective, as fungi become resistant to commonly used chemicals. Environmental regulations are also restricting levels and types of chemical applications. Lemon packinghouse managers, as one example, are looking for economically viable alternative strategies for decay control. One strategy which was tested and compared in three central California packinghouses involved a multifaceted programme of packinghouse redesign, daily sanitation, and regular monitoring of Penicillium spores in the atmosphere. Results indicate that the isolation of spores by segregation of decayed fruit can be more effective and economically efficient than increased fungicide use or additional attention to cleansing and sanitation alone.

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There are more references available in the full text version of this article.

Cited by (8)

Performance of fogged disinfectants to inactivate conidia of Penicillium digitatum within citrus degreening rooms
2014, Postharvest Biology and Technology
Citation Excerpt :
Sanitizers destroy microbes on contact and provide no residual protection. Sanitation by chemical or other means can substantially reduce losses and can be an economically viable option to the use of fungicides (Gardner et al., 1986) and the management of fungicide-resistant isolates of pathogens (Hall and Bice, 1977). Sanitation of the entire packinghouse environment is important (Bancroft et al., 1984), but some portions of the facilities have an acute need for sanitation.
Fogging with formaldehyde of citrus packinghouses when the fruit are absent is a practice to control conidia of Penicillium digitatum (Pers.) Sacc., the cause of citrus green mold. Replacements for formaldehyde in these facilities are needed because of worker and environmental health issues. To evaluate the effectiveness of candidate sanitizers, craft wood sticks with conidia of P. digitatum were attached throughout commercial citrus ethylene degreening rooms and either water alone or the sanitizers were applied. The rooms were 20 ± 2 °C and humidified to 85–90% relative humidity. Aldehydes, peroxygen compounds, sodium hypochlorite, chlorine dioxide, quaternary ammonium, alcohols, one phenolic compound, and one organic acid were applied with a compressed air assisted atomizer or fan atomizer in a volume of approximately 6 L per 100 m³ of room volume dispensed over a 3 h period. Rates applied were expressed as active ingredient per m³ of room volume. All were compared to formaldehyde applied at 1.98 g m⁻³ of room volume. After 24 h, the craft wood sticks were retrieved, and germination of the conidia assessed. Five sanitizers reduced germination of conidia by more than 95% and equaled formaldehyde in effectiveness. They were (effective rates): (1) glutaraldehyde (0.1 g m⁻³); (2) hydrogen peroxide (4.4 g m⁻³); (3) Citrisol (1.0 g m⁻³), a proprietary mineral oxychloride oxidizer; (4) acetic acid (5.3 g m⁻³); and (5) peracetic acid (2.4 g m⁻³). The toxicity of effective sanitizers was determined by exposure of P. digitatum conidia for 10 min to concentrations of each and the proportion of survivors used to estimate EC₅₀ and EC₉₉ concentrations. The toxicity of the sanitizers in this assay did not predict their effectiveness when applied by fogging, probably because other factors, such as distribution, persistence, droplet size, or vapor pressure also influenced their effectiveness.
Control of Penicillium expansum with potassium phosphite and heat treatment
2011, Crop Protection
Citation Excerpt :
In addition to the postharvest losses that can be consequent, infections by Penicillium spp. are generally associated with mycotoxin production and accumulation in processed apples. Beside certain prophylactic measures applied to reduce the amount of inoculum in the storage environments, the most effective strategy against Penicillium spp. so far is the use of fungicides at harvest and during packaging (Gardner et al., 1986). For decades, benomyl and thiabendazole, imazalil, and sodium ortho-phenylphenate (SOPP), which belong to the benzimidazole (BZI), sterol demethylation inhibitor (DMI), and phenyl-phenol chemical classes, respectively, were the most commonly used fungicides until the recent introduction to the market of pyrimethanil (anilinopyrimidine) and fludioxonil (phenylpyrrole).
Potassium phosphite (Phi) was evaluated for its in vitro activity against Penicillium expansum and for its potential long-term efficacy against postharvest blue mold infections on apple fruit. Phi amended to malt extract agar medium at 2 and 4 mg/ml completely inhibited mycelial growth and conidial germination, respectively. Conidia of P. expansum suspended for 3 min in a solution of 2 mg/ml Phi at 20 °C or heated to 50 °C germinated at 53 and 0%, respectively. Disease incidence of P. expansum on Elstar apples wounded and inoculated with a thiabendazole-resistant isolate was reduced significantly (P = 0.01) following a curative treatment with Phi at 2 mg/ml. When applied on freshly harvested unwounded Elstar apples, Phi (2 mg/ml) reduced blue mold incidence about three-fold compared to the control and was found to be as effective as thiabendazole against natural blue mold infections after six months of storage at 2 °C. Our results suggest that potassium phosphite has a potential to be part of the general management program implemented for the control of postharvest blue mold infections on pome fruits.
Characterization of fungicide-resistant isolates of Penicillium digitatum collected in California
2007, Crop Protection
Isolates of Penicillium digitatum, cause of citrus green mould, were collected in California from infected fruit from packing houses or groves. The fungicide sensitivity of 166 isolates to imazalil (IMZ), thiabendazole (TBZ), sodium ortho-phenylphenate (SOPP), and pyrimethanil (PYR) were determined. All of these fungicides except PYR were in use in packing houses. None were used in groves. Isolates resistant to IMZ, TBZ, and SOPP occurred within packing houses but not in groves. Many were simultaneously resistant to two or more fungicides. Resistance to PYR was found only in three isolates from relatively isolated groves in northern California. The EC₅₀ levels of IMZ and SOPP among resistant isolates varied, while those resistant to TBZ were primarily of one level. The colony colour, lesion expansion rate and days to sporulate on infected lemons, and the magnitude of sporulation were determined for many isolates. Some minor alterations in colony colour and a slightly reduced lesion size occurred among fungicide-resistant isolates, particularly those resistant to more than one fungicide. Lemons were inoculated with a mixture of conidia from one sensitive and one resistant isolate in equal portions, and then conidia were collected one week later from lesions. The resistant isolates were all resistant to IMZ and some were also resistant to SOPP and TBZ. The proportion of IMZ-sensitive and -resistant conidia was determined and comprised the inoculum to initiate a subsequent decay cycle. A total of 28 pairs of sensitive and resistant isolates were evaluated over four cycles. IMZ-resistant conidia declined rapidly in 26 pairs; few or no IMZ-resistant conidia were present after four cycles. In two pairs the resistant conidia persisted over four cycles with little decline, which suggests that in the absence of IMZ use some resistant isolates may persist for long periods. All of the fungicides would effectively control green mould on fruit arriving from groves with incipient infections, because sensitive isolates predominate there, however, control of infections initiated within packing houses, where resistant isolates predominate, remains a difficult problem. The recently introduced PYR controls resistant isolates that now occur in packing houses, but resistance to this fungicide, which was detected in three isolates from locations where PYR had not been used, indicates it must be used with good resistance management practices.
Alternative treatments for postharvest control of blue mold in ‘Fuji’ apples
2017, Acta Horticulturae
Biointensive integrated pest management in horticultural ecosystems
2014, Biointensive Integrated Pest Management in Horticultural Ecosystems
Comparative studies of Plumería species for their phytochemical and antifungal properties against Citrus sinensis pathogens
2012, International Journal of Agricultural Research

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Crop Protection

Abstract

References (18)

Imazalil: a new weapon in the fruit decay battle

Citrograph

Comparison of decay control strategies in California lemon packinghouses

Plant Disease

Resistance of decay fungi to benzimidazole fungicides used in Florida citrus packinghouses

Problems of decay control in marketing citrus fruits: strategy and solutions, California and Arizona

Control of postharvest diseases

Postharvest diseases of citrus fruits

Outlook on Agriculture

Case study 5: Penicillium decay of citrus fruits

Resistance to benizimidazole fungicides of Penicillium italicum and P. digitatum isolated from packinghouses and orchards in Egypt

Plant Disease

Biological aspects of citrus molds tolerant to benzimidazole fungicides

Phytopathology

Cited by (8)

Performance of fogged disinfectants to inactivate conidia of Penicillium digitatum within citrus degreening rooms

Control of Penicillium expansum with potassium phosphite and heat treatment

Characterization of fungicide-resistant isolates of Penicillium digitatum collected in California

Alternative treatments for postharvest control of blue mold in ‘Fuji’ apples

Biointensive integrated pest management in horticultural ecosystems

Comparative studies of Plumería species for their phytochemical and antifungal properties against Citrus sinensis pathogens