Papaya postharvest diseases and economic consequences in tropical countries

Carica papaya is cultivated primarily for its nutritional and economic benefits to papaya farmers and exporting countries, but this climacteric fruit depreciates at a higher rate due to postharvest spoilage associated with poor handling and increase in microbial activities.

The focus of this paper is to identify and discuss underlying factors undermining the growth of the papaya industry globally. In doing this, consideration is given to the epidemiology of common postharvest fungal infections of papaya.

Since some of these diseases were already incubating in the field, control measures shall also incorporate field practices. The perceived future of the papaya industry based on current research is highlighted. We also represented our experience in a model (research and demonstration) C. papaya farm that may help improve papaya cultivation and fruit yield.

Introduction

Carica papaya is a dynamic fruit crop cultivated widely in tropical and subtropical regions like India, Nigeria, Brazil, Mexico, and Indonesia [1, 2]. It is ranked as the fourth most popular tropical fruit after banana, mango, and pineapple [3]. In recent years, the global papaya production has grown significantly contributing to the economy, with an estimated production of over 13 million metric tons annually [4].

Notwithstanding its economic importance, postharvest diseases due to fungal and bacterial infections is a major concern tofarmers [5]. A recent study by Lalpekhlua et al., shows that up to 35% of harvested papaya is lost due to postharvest diseases, which leads to considerable financial setbacks for farmers,
exporters, and traders [6]. Due to the high nutrient content of papaya and loss of bioactive compounds following rapid ripening, fruits are highly susceptible to postharvest microbial activities resulting in spoilage [2, 5, 7], especially under poor handling and storage conditions [8].

Though majority of the spoilage microorganisms are present on the fruit surface while in the field before harvesting, their metabolic activities are accentuated by ripening of fruit and mechanical injuries that facilitate microbial access to the nutrient laden endosperm [2, 7].

In the opinion of Seress et al., the astronomical world population growth, which is estimated to hit 10 billion in 2026 would have a negative effect on food security and industry striving in association with the huge postharvest losses in Carica papaya fruit markets [9].

The presence of disease symptoms on fruits such as rots, lesions and off odor reduce the market acceptability of fruits whether for direct consumption or as industrial raw material. A staggering rejection rate ranging from 20-40% of all fruits reaching the papaya market had been associated with environmental factors such as high humidity, warm temperatures, and inadequate ventilation [8].

Common postharvest diseases

Postharvest diseases of Carica papaya are cause primarily by fungal pathogens, and some bacterial infections which contribute to fruit deterioration. They present major challenges to papaya production which can cause severe damage during storage, marketing and transportation, leading to severe economic losses and limit export opportunities [10].

Anthracnose, Fusarium Rot, Phytophthora Fruit Rot, Aspergillus Rot are common prevalent postharvest diseases affecting papaya. Singh et al., proposed the use of pathogen resistant seeds of C. papaya varieties as cultivars to suppress disease occurrence and presented a classification protocol for selecting resilient varieties [11]. Widespread application of these varieties as may be adapted to different climatic conditions and soil type may proffer possible solution to C. papaya disease first in the field and then postharvest. 

Table 1 of the original paper - Common postharvest diseases of Carica papaya

Contents

     Anthracnose
     Fusarium Rot
     Phytophthora Ro
Predisposing factors to infection and preliminary control measures
Economic consequences
Management strategies for postharvest diseases of Carica papaya

Discussion and conclusion

In this paper we have been able to demonstrate the inherent economic gains in Carica papaya fruit which account for its cultivation in many tropical and subtropical countries across the world. It is equally important to emphasize that studies have indicated beneficial properties in the plant's leaf and stem. In their study, Oladele et al., demonstrated increased tensile strength in a glass-papaya stem mix ]34] which may find application in building and construction works.

Furthermore, the antimalarial property of Alstonia boonei and C. papaya leaves extracts when combined demonstrated enhanced synergies [35], validating the pervading use of different plants concoctions in the treatment of diseases in many rural and periurban settings and an emerging and increasing agitation to explore the use of plants with proven medicinal properties for both prophylaxis and curative treatment of many diseases especially neglected tropical diseases.

The anticorrosion property of Carica papaya leaf extract was demonstrated on mild steel [36] further expanding the application of this veritable crop onto aviation, maritime and oil exploration, industries with major corrosion challenges.

Bello and colleagues showed comparable adsorbent properties between activated carbon and chemically modified pawpaw leaf [37], and thus a potential adsorbent for removal of toxic compounds including heavy metals in raw water and effluent.

In concomitant with all these co-benefits, farmers and traders in papaya languish annually from disease incidence with decline in productivity of industry with papaya as a major raw material. It is therefore imperative to continue to develop and explore innovative practices in controlling and preventing C.
papaya diseases both in the field and postharvest.

In our experience, we were able to maintain a disease-free C. papaya orchard on a 2 ½ acre for four seasons post first harvest (Figure 1 of the original paper, see below) with bountiful harvest by simply implementing Good farm management of regular weeding, removal of fallen stands and application of pesticides prior to fruiting.

When we recorded the first disease incidence it was on older stands stems which subsequently served as reservoirs for leaf and fruit infections. Then our attention shifted to removing older stands from the farm.

This practice was profitable as yield per stand declined after the third harvest season while at the same time disease susceptibility increased, so early replacement of older stands with new stands was both cost effective and disease control strategy.

This practice is cost effective and les laborious and we thus recommend it to small scale and médium scale papaya farmers.

Sources

Postharvest Diseases of Carica papaya Fruit and Economic Consequences: Predisposing Factors and Control Management Strategies
Chikaodi Bianca JOSEPH, Louis Osayenum EGWARI, Abiola Folakemi Olaniran
NIPES-Journal of Science and Technology, Research Vol. 7, Special Issue: Landmark University International Conference SEB4SDG 2025, pp. 1842–1846
ACCESS to the full paper 

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