Rice is a staple food for most Indonesians and is consumed with all three meals a day, providing necessary nutrition. Several obstacles to achieving optimal production are common, such as water scarcity, climate change, and biotic factors, such as insect pests, diseases, and weeds (Siagian et al., 2020). One of the rice’s most damaging insect pests is Scirpophaga incertulas Walker (Lepidoptera: Crambidae), the yellow stem borer of rice (YSB). In Indonesia, especially on the island of Java, YSB is a widespread, dominant, and destructive pest. The total damage caused by YSB is 35,543 ha in the 2022 planting season, which is the highest compared to other rice pests in Indonesia (Tanaman, 2022). It is also forecasted to increase to 48,838 ha in the 2023 planting season (Tanaman, 2022). This forecast indicates that YSB potentially can cause the most severe damage to rice in Indonesia.

YSB larvae attack rice plants by feeding internally and causing damage by tunneling. During the vegetative stage, the borer larvae will attack the tillers. With no translocation, tillers dry-up and die, symptoms commonly known as deadhearts. At the generative phase, the damage is indicated by empty panicles of striking whitish color called whiteheads (Gautam et al., 2020). In Indonesia, the damage levels can go up to 30% (Ramadhan et al., 2020); Bahar et al. 2020). This pest can cause significant yield loss in Asia (Heinrichs & Muniappan, 2017).

Insecticide application is the only method frequently used. Several studies showed that the intensity of synthetic insecticide usage in Indonesia’s rice production is very high.(Wiyono et al., 2014) reported that synthetic pesticide usage in Karawang (West Java) and Klaten (Central Java) was about 11 and 12 times per planting season. However, control is less effective because the larvae are protected by the stems of rice plants and improper timing of insecticide applications (Bandong & Litsinger, 2005). Furthermore, some reported that the level of knowledge about pesticides was not following the application of good agricultural practices for pesticide use (Istriningsih et al., 2020). Over-dependence on insecticides can adversely affect the bioecology of rice fields, insect resistance, and resurgence (Kartohardjono, 2011).

One of the approaches in integrated pest management (IPM) is to manage insect pests sustainably and effectively by integrating all possible solutions. As a foundational practice, pheromone-mediated mating disruption (MD) is an effective way to practice IPM. MD is a strategy to disrupt chemical communication between males and females through competitive and non-competitive mechanisms to prevent mating and reproduction of the target insect pest (Rizvi et al., 2021). The benefits of this technology are that it is species-specific and non-hazardous to beneficial insects and humans (Witzgall et al., 2010).

MD has been used to manage agricultural pests in more than 800,000 ha of crops for the past 30 years (Benelli et al., 2019). In Spain, to control striped stemborer (Chilo suppressalis (Walker) (Lepidoptera: Crambidae)), MD has been applied on around 10,000 ha annually (Casagrande, 1993). MD has also been used to manage YSB. According to growers practice in India, a study by(Cork et al., 1996) showed that the treated plot with MD significantly reduced whitehead damage compared to plots treated with insecticide.

The successful cases above indicate that MD technology is a promising strategy in insect pest management and can be applied to manage YSB. The traditionally high cost of synthesizing insect sex pheromones has been a barrier to adopting this technology in low-cost, large-hectarage row crops(Holkenbrink et al., 2020) Provivi^®, with our innovation and breakthrough technology, uses proprietary methodology (bio-catalysts) and low- cost raw materials to reduce the steps needed to synthesize pheromones (Wampler et al., 2021). Production of pheromones at a large scale and with reduced costs enables affordable pheromone products and the adoption of this technology in rice is economically viable for grower. With an affordable pheromone dispenser, the integration of MD technology into conventional grower’s pest management will be easier and will help to reduce the number of insecticide applications to protect yield in a season. Reduced insecticide application for YSB will help the grower to reduce production cost and minimize the negative impact of insecticide to the rice ecology as well (Witzgall et al., 2010). Slow-release dispensers filled with YSB sex-pheromone (Pheron™ RSB) were evaluated in wide-area trials to understand the benefits of MD. Though there were few studies conducted to understand MD on YSB, none were from Indonesia and at such large scale. Our objective here was to compare trap reduction, crop damage, number of insecticide usage, and yield protection in pheromone foundational practice (PFP) to conventional grower practice (CGP) across rice- producing provinces of Java Island, Indonesia, in two consecutive seasons. Therefore, in this large- scale study we evaluate MD as an alternative, novel, practical and season-long foundational tool for implementing integrated pest management of YSB in rice agroecosystem.

Scirpophaga incertulas, the yellow stem borer (YSB), has been determined to be the most damaging rice pest in Indonesia (Tanaman, 2022). The larvae can cause tiller damage and empty panicles, which can potentially cause harvest losses and ultimately failure. Current insect pest management in Indonesian rice largely depends upon conventional insecticides(Prihandiani et al., 2021). The more challenging the insect pest control is the higher the number of insecticide applications. Often, insecticide applications are ineffective as the larvae are protected inside the rice stems (Nurhasanah et al., 2020). Field studies conducted by (Fox & Winarto, 2016) and (Prihandiani et al., 2021) on Java Island, Indonesia, reported that 60% of rice growers used three to five different active ingredients mixed in one spray solution. Almost 80% of growers sprayed 7 to 13 times per rice growing season.

Such intensive applications with synthetic conventional insecticides has negative impacts on the environment, such as the development of insecticide resistance, resurgence or secondary pest explosions, elimination of non-target organisms, and accumulation of insecticide residues in the field (Baehaki, 2013). Croplife Indonesia confirmed insecticide resistance to diamide insecticide class in YSB populations collected from West Java, Indonesia (I.R.A.C., 2016). Though integrated pest management (IPM) approaches are well-known, most are not considered as practical solution by Indonesian rice growers. Pheromone- mediated MD can reduce YSB reproduction rate and resulting larval populations; thus, reducing the number of necessary insecticide applications (Rizvi et al., 2021).

In the past decades, lepidopteran sex pheromones have been used in many pest control techniques such as lure-and-kill, mass trapping, auto-confusion, and mating disruption (Cork et al., 2008). Lepidopteran behavioral control for pest management by MD uses field-wide application of synthetic species-specific sex pheromones to disrupt pheromone-mediated communication between the sexes of the target species, this technique is a practical tool for pest management (Miller & L.J., 2015). However, compared to other techniques, MD requires more pheromone content to be released and potentially more costly (Cork et al., 2008). Furthermore, proving this technology in large area crops like rice is challenging due to the cost of sex-pheromone synthesis along with development of an efficient formulation that can last a season-long (Holkenbrink et al., 2020). Through proprietary (bio)catalysts and low- cost raw materials, Provivi^® is able to produce pheromones on a large-scale at low cost (Wampler et al., 2021). As such, Provivi^® is the first company to register pheromone-mediated MD in Indonesia to manage YSB in rice. Syngenta^® Indonesia in partnership with Provivi^® has commercialized Nelvium™ Powered by Pheron™ RSB in 2022 in Indonesia.

Typically, larger rice fields are required to understand the efficacy of MD. It is also important to utilize wider field plot areas to reduce the migration of mated YSB females flying into pheromone-treated areas for oviposition which can result in damage (Cork et al., 1996). Thus, the concept of minimum field size is an important consideration for MD trials. Previously, we tested the Pheron^™ RSB in 1, 2, 4, and 9 ha rice fields at multiple dose rates. Our internal results (Provivi internal, unpublished data) determined that higher MD is achieved in areas where dispensers were installed in ≥4 ha. The maximum benefits of MD, reduction in damage caused by YSB larvae is also lower in larger areas, compared to <2ha. Lower insecticide applications were noticed when dispensers were installed in larger areas of rice. This phenomenon is very similar to other crop pests, where the efficacy of MD increases with increase in effective area (R. et al., 2014); (Cork et al., 2008). In this MD study, the effectiveness of Pheron™ RSB dispensers were examined at the registered rate of 20 dispensers/ha at the minimum 4 ha PFP plot size with 200 m distance of buffer zone from the CGP fields. Pheron^™ RSB was tested at 74 sites in 3 provinces on Java Island with 1,282 participating growers during the dry and wet seasons to investigate further how Pheron^™ RSB dispensers work in diverse conditions such as pest population density, weather, varied environmental conditions, and growers’ practices. The efficacy of Pheron™ RSB was measured via reduction of YSB male moth captures in lure traps, damage reduction, insecticide application rates and frequency, and potential for yield protection compared to conventionally managed fields (Cork et al., 1998).

Reduction of YSB male moth captures is an indication that the MD is working because the pheromone emitting dispensers interfere with the YSB male’s ability to focus on female sex pheromone or synthetic pheromone from lure inside the trap (as well as calling YSB females), which then hinders the male from locating these pheromone’s sources (Bartell, 1982). Median trap reduction in both seasons was very similar, where trap reduction was higher than 70% until the vegetative phase of the rice crop (~45 days after installation). This is when the pest pressure is relatively higher, and the crop is attractive for adult YSB moths and. Trap reduction during reproductive stages was higher than 40% until harvest in both dry and wet seasons of 2020– 2021. The results were similar to the studies by (Cork et al., 1998), where MD with a 2-component YSB blend consisting of (Z)-9-hexadecenal and (Z)-11-hexadecenal, at an application rate of 40 g AI per ha per season gave a trap reduction of 65% to 85% for initial 50 days of the crop period. A lower percentage of trap reduction may not indicate that the moths in PFP plots can mate (Cardé & Elkinton, 1984). We still need to understand the optimal and effective trap reduction of YSB. Further studies need to be done to correlate trap reduction and direct measures of MD via tethered virgin females or mating tables (McVeigh et al., 1983).

Despite the lack of direct measures, we can still indirectly determine MD’s effect by assessing the infestation of YSB (Cork & Basu, 1996). The results from the two seasons study through rice crop damage assessment showed that tiller damage by YSB in PFP plots was significantly lower compared CGP plot, with a median of 40% and 46% damage reduction in the wet season and dry season, respectively and. The large area of a 4 ha plot in PFP with 80 points sources of pheromone-emitting dispensers created an effective MD. This MD area decreases the YSB reproduction rate and larval number in the field, which may lead to fewer deadheart and whiteheads caused by feeding damage (R. et al., 2014). The large area in our study has also reduced the likelihood of gravid female moth migration into PFP plots. The first generation of female moths of YSB would disperse into an attractive and suitable rice crop for oviposition. A mated female YSB tends not to fly considerable distances to reduce predation and mortality (Cork et al., 2008). This result is aligned with a study done in India which observed a significant decrease in YSB damage in a wide area of MD treatment compared to plots with conventional insecticide management(Cork et al., 2008).

Significantly lower damage in the PFP plots also positively affects other parameters, such as the number of insecticide applications and grain yield. Yield is a factor of many parameters, such as soil health, cultivation practices, timely irrigation, and crop protection from weeds and diseases. However, yield loss is possible when an insect pest such as YSB directly impacts the grains produced per tiller. Protecting the crop from YSB with MD with Pheron™ RSB has resulted in higher harvested grain yield than CGP. An increase of 0.43 tons/ha of grain yield in the wet season and 0.76 tons/ha in the dry season in PFP compared to CGP could be attributed to MD. This higher yield has been contributed by a healthy tiller and more filled grains in PFP plots compared to the CGP plot. The yield increase in MD treatment plots for managing YSB was also reported by(Cork et al., 1998), where it provided a 10% higher yield compared to insecticide-treated plots and a 25% higher yield compared to plots without insecticide application.

Though a mandatory insecticide was applied in PFP plots as a prophylactic spray, insecticide usage to manage YSB in PFP saw a 40 to 56% reduction compared to CGP. Similarly, (Welter et al., 2005)confirmed that MD in wide areas of plantation and row crops provided significant insecticide application reduction and maintained low damage. Studies done in India on YSB by (Cork et al., 1998) reported that conventional growers’ practice plots sprayed two additional rounds of insecticides to manage YSB compared to MD plots. The benefits of reducing insecticide application include conserving natural enemies, managing insecticide resistance, and reducing harmful chemical residue to the environment and humans. All these will significantly benefit rice’s sustainable production and create economic benefits for the growers.

Provivi^® has made considerable progress in developingpheromone-basedtechnologytomanage yellow stem borer (YSB), where prophylactic, calendar-based applications are typical. Without alternative, practical, and adaptable technologies, pest resurgence, resistance, and residues from toxic insecticides is unavoidable. Pheromone- mediated mating disruption provides an alternative to insecticide applications. Research conducted at 74 locations across Java Island in multiple seasons in 2020-21 supports the proposition that fields treated with Pheron™ RSB incurred lower YSB damage, fewer insecticide applications, and yield protection compared to conventional practices. The results suggest that mating disruption offers smallholders a more efficacious means of control than current management practices. Pheromone-based insect management is a zero residue, non-detrimental to humans and the environment. This work and commercial adoption of Pheron™ RSB by growers in 2022–2023 across Java Island of Indonesia suggests it is sufficiently robust to extend it to other countries to manage YSB.