Globally, the cultivation of oyster mushrooms (Pleurotus spp.) has expanded due to their high nutritional value, low production costs and ability to convert agro-industrial waste into high-value food products. Beyond their nutritional role, mushroom cultivation exemplifies circular-economy principles by recycling agricultural residues while generating employment opportunities in rural communities (Chang and Miles, 2004). In tropical developing countries such as the Philippines, oyster mushroom production offers a sustainable livelihood strategy; however, it remains small-scale and labor-intensive, relying heavily on manual watering or misting. These practices often result in inconsistent humidity and temperature levels, leading to uneven fruiting, increased contamination and reduced yields, as mentioned by Tejada et al., (2023). Oyster mushrooms require a temperature range of 24-30°C and relative humidity between 80-90% for optimal fruiting (Sher et al., 2010). Deviations from these thresholds affect mycelial respiration, primordia formation and the balance of substrate moisture. Manual humidity control is typically imprecise, leading to either desiccation or excessive moisture that favors the growth of pathogenic organisms. Automated fogging and misting systems, when properly calibrated, can maintain microclimate equilibrium by generating fine droplets and enabling closed-loop regulation of relative humidity and air temperature. These factors directly influence biological efficiency, yield stability and product quality as reported by Lenka et al., (2022). Recent studies have demonstrated the potential of automation and Internet of Things (IoT)-based systems to optimize environmental control in mushroom production. Chong et al., (2023) reported that an IoT-controlled monitoring system significantly enhanced mushroom yield and quality by maintaining consistent temperature and humidity. Similarly, Rukhiran et al., (2023) integrated solar energy with IoT automation for sustainable mushroom cultivation, while Guragain et al., (2024) introduced a low-cost, centralized IoT ecosystem designed for small-scale growers. Nguyen et al., (2024) employed edge-computing and sensor-camera systems to achieve precision microclimate management and Elewi et al., (2024) developed a cost-aware automation model tailored for Pleurotus ostreatus cultivation. Collectively, these studies affirm the role of automation in improving productivity, environmental stability and labor efficiency in controlled cultivation systems. In the Philippines, research has primarily focused on optimizing substrates such as rice straw, banana leaves and sawdust (Tejada et al., 2023) or developing postharvest drying technologies (Hung et al., 2020). However, few studies have investigated automated humidity-control systems adapted to tropical mushroom houses and resource-constrained rural settings. Thus, a critical gap remains in locally validated automation models suitable for smallholder operations. This study is among the first to design and evaluate an Automatic Fogging System (AFS) specifically customized for tropical Philippine conditions. Unlike prior IoT models developed for temperate greenhouses, the AFS integrates locally available components-humidity and temperature sensors, control units and misting modules-engineered for semi-open fruiting houses. The system automates fogging intervals and environmental feedback loops to sustain optimal growth conditions. Therefore, the study aims to (1) assess the efficiency of AFS on oyster mushroom yield, (2) establish control measures for disease occurrence, (3) determine productivity and profitability under AFS, (4) compare performance with traditional farmers’ practice and (5) evaluate the biological efficiency and acceptability of Pleurotus florida and P. ostreatus.
       
By validating the AFS under real tropical conditions, this research advances innovative and sustainable agriculture in the ASEAN region. Its findings provide an empirical foundation for scalable, low-cost microclimate control technologies that enhance productivity, reduce water use and promote technology adoption among smallholder mushroom growers in the Philippines.

Research design and location
 
The study employed a comparative experimental design to assess the performance of an Automatic Fogging System (AFS) developed for oyster mushroom (Pleurotus spp.) production. The experiment was conducted at the Mushroom Production Facility of the Abra State Institute of Sciences and Technology (ASIST), Lagangilang Campus, Abra, Philippines (17°36' N, 120°44' E), from November 2024 to March 2025. The site has a tropical monsoon climate, with average ambient temperatures ranging from 23 to 32°C and relative humidity between 70% and 90%. Two identical culture rooms were used: one equipped with the AFS and another managed through farmers’ practice (FP), which involved manual misting. Both chambers measured 3 m x 4 m x 2.5 m and shared identical ventilation and lighting conditions.
 
Description of the automatic fogging system (AFS)
 
The AFS was locally fabricated using low-cost, readily available components. It comprised:
• Sensors: DHT22 humidity and temperature sensors continuously monitor microclimate conditions.
•​ Control unit: Arduino Mega 2560 microcontroller programmed to activate fogging when RH < 80% and to deactivate when RH > 90%.
• Fogging unit: A six-head ultrasonic fogger (24 V DC, 1.7 MHz piezoelectric transducers) distributing mist through PVC ducts.
• Power supply: 12 V/10 A regulated adapter with surge protection.
• Alarm and display module: Digital screen with alert buzzer showing real-time readings.
       
The AFS operated automatically without manual input. The FP control treatment involved hand spraying twice daily (07:00 and 15:00 h) using a pressurized sprayer.
 
Experimental materials
 
Two oyster mushroom species were used (Table 1), white oyster (Pleurotus florida) and brown oyster (P. ostreatus), both obtained from the ASIST Mushroom Laboratory. The substrate mixture consisted of rice straw (80%), sawdust (15%) and rice bran (5%), which was moistened to 65% and sterilized at 100°C for 4 hours. Each 1-kg bag was inoculated with 5% spawn (w/w) and incubated for 15 days before being transferred to fruiting chambers.


       
Each treatment involved 150 fruiting bags, replicated three times (total = 450 bags per system). Water and substrate sources were standardized across treatments.
 
Data collection and measurements
 
Microclimate parameters (temperature and RH) were logged every 30 minutes using digital dataloggers integrated into the AFS and handheld hygrometers for FP. Recorded data were downloaded daily for analysis.
       
The following indicators were evaluated: total yield, biological efficiency, average fruit body weight, number of fruit bodies, contamination rate, temperature, relative humidity and return on investment (Table 2).


 
Data analysis
 
Data were subjected to Analysis of Variance (ANOVA) using a two-factor factorial design (cultivation system x mushroom species). Mean differences were evaluated using Duncan’s multiple range test (DMRT) at 5% significance. The relationships between yield and environmental parameters were analyzed using the Pearson correlation coefficient. All analyses were carried out using Microsoft Excel.
 
Ethical and safety considerations
 
The experiment adhered to the Bureau of Plant Industry (BPI) guidelines for mushroom culture sanitation, waste disposal and workplace safety. Electrical components were enclosed and operated at low voltage (≤24 V DC) to minimize the risk of shock and fire.

Microclimate performance
 
The Automatic Fogging System (AFS) maintained a stable relative humidity (RH) of 82-89% and an average temperature range of 25-28°C throughout the fruiting period, whereas the Farmers’ Practice (FP) treatment fluctuated widely between 65-94% RH and 23-33°C. These findings confirm that the AFS effectively regulated the microclimate within the optimal physiological thresholds required for oyster mushroom fruiting, as mentioned by Sher et al., (2010). On the other hand, consistent humidity and temperature are critical for maintaining mycelial vigor and primordia formation. Similar outcomes were reported by Chong et al., (2023), who demonstrated that IoT-controlled humidity systems significantly reduced environmental variability, thereby increasing fruiting uniformity. Likewise, Nguyen et al., (2024) observed that automated systems leveraging sensor feedback loops minimized daily fluctuations by more than 60%, supporting the current study’s findings.
 
Yield and biological efficiency
 
Table 3 summarizes the mean yield and biological efficiency (BE) of the two species under AFS and FP. Analysis of variance (ANOVA) revealed significant differences (p<0.05) in both yield and BE between AFS and FP. The interaction effect between cultivation system and species was not significant (p>0.05), indicating that both P. florida and P. ostreatus responded similarly to automated humidity control. The 28-31% increase in BE under AFS aligns with reports by Guragain et al., (2024) and Rukhiran et al., (2023), who found comparable gains using IoT-regulated environmental systems. These results emphasize that precise humidity regulation enhances substrate metabolism and water-absorption efficiency, both of which are directly proportional to fruit body biomass (Sharma et al., 2020).


 
Contamination rate and disease control
 
Contamination rates in the AFS chamber averaged 3.1%, significantly lower than FP’s 9.8%. Reduced contamination can be attributed to uniform humidity distribution and minimized surface wetness, which inhibit the proliferation of mold and bacteria. Similar patterns were observed by Elewi et al., (2024), who reported that automation reduced disease incidence by maintaining stable vapor pressure differentials within the cultivation area. The reduction in contamination also implies improved air circulation and fewer manual interventions, thereby reducing potential sources of vector contamination (Jha et al., 2025). This finding supports earlier assertions by Rukhiran et al., (2023) that automation not only enhances yield but also contributes to biosecurity and consistent product quality.
 
Profitability and return on investment (ROI)
 
Economic analysis revealed that the production cost per 150-bag replicate was slightly higher under AFS due to initial hardware expenses; however, the overall ROI increased by 18-22% compared with FP (Table 4). Higher profitability under AFS resulted from increased yield and reduced labor costs (elimination of manual misting). These outcomes corroborate findings by Elewi et al., (2024) and Nguyen et al., (2024), who documented labor reductions of 30-40% with automated control systems. Thus, while initial investment is higher, the payback period is short, making the AFS economically viable for smallholders.

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The Automatic Fogging System consistently maintained optimal humidity and temperature, significantly increased yield and biological efficiency, reduced contamination and improved profitability compared with manual practices. These results confirm that low-cost, locally developed automation can effectively address major constraints in mushroom production, particularly unstable microclimatic conditions and labor inefficiency. The technology offers a practical, scalable model for smart, sustainable and climate-resilient mushroom production in the Philippines and across ASEAN. Future studies may evaluate its adaptability for the domestication and controlled cultivation of selected wild edible mushroom species in the Cordillera region to support biodiversity conservation and livelihood development.

The present study was supported by the Department of Science and Technology-Cordillera Administrative Region (DOST-CAR) and the Department of Science and Technology – National Research Council of the Philippines (DOST-NRCP). The authors also acknowledge the Abra State Institute of Sciences and Technology for institutional support.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy of the information provided.
 
Informed consent
 
Not applicable.     

The authors declare that there are no conflicts of interest regarding the publication of this article.