A sprayable pheromone formulation could provide organic cranberry growers with an additional, targeted tool for managing blackheaded fireworm as part of integrated pest management programs.
Key takeaways
An organically approved microencapsulated pheromone formulation reduced mating by blackheaded fireworm resulting in fewer next-generation larvae and less cranberry fruit damage.
The formulation can be applied using conventional farm spraying equipment and reapplied during periods of blackheaded fireworm flight. This may make pheromone application more practical for cranberry production compared to previous dispensing systems.
Further research is needed to determine how consistently the microencapsulated formulation reduces crop damage under commercial production conditions and how it can best be integrated with other pest management practices.
The researchers caution that evaluating pheromone mating disruption based only on indirect measures such as male trap captures may be misleading. Measuring female mating and subsequent larval populations provides a more robust evaluation.
The blackheaded fireworm (Rhopobota naevana) is one of the major insect pests of cranberry production and is particularly important on organic cranberry farms in Quebec. During its larval stage, the insect feeds on cranberry leaves, buds and fruit. Severe infestations can cause devastating yield losses.
Organic cranberry growers have relatively few insecticide options for managing this pest, and use and effectiveness of available biopesticides can be limiting. This creates a need for alternative approaches that can control pests while fitting within organic production and integrated pest management systems. Mating disruption is one such approach.
Like many moths, blackheaded fireworms use sex pheromones to find mates. Females release a chemical signal, and males follow that signal to locate potential mates. Mating disruption takes advantage of this communication system. The objective is to fill the crop environment with enough synthetic pheromone that males have difficulty locating females. If fewer females are successfully mated, there should be fewer offspring and, ultimately, less crop damage.
Mating disruption has been previously tested in cranberry fields but practical challenges have limited its success. Some approaches rely on pheromone dispensers, which require large numbers of individual devices to be distributed throughout the field. Mega-dispensers, on the other hand, require fewer units per hectare but can result in uneven pheromone coverage, creating untreated areas or areas of concentrated pheromone while also increasing costs.
As part of an OSC4 research activity on cost-effective integrated management of cranberry insect pests, researchers tested a new sprayable microencapsulated pheromone (MEC) formulation. The study was led by Cyrane Pouët, a PhD student working with Dr. Éric Lucas at UQAM, and is published in the Journal of Economic Entomology.
How was the research done?
The study was conducted over two growing seasons on commercial organic cranberry farms in Quebec’s Centre-du-Québec region. At each farm, researchers compared MEC pheromone-treated plots with untreated control plots.
The organically approved MEC formulation was provided by research partner TRÉCÉ Inc. and was loaded with the main component of the blackheaded fireworm’s sex pheromone. It was mixed with water and applied to fields using the growers’ existing spraying equipment. Four applications were made throughout the growing season, beginning when the first major fireworm moth flight was observed and targeting the periods when moths were most active.
Researchers evaluated the treatment at several stages:
Adult males: Pheromone-baited sticky traps were used to monitor male flight activity.
Female mating: Adult insects were collected with sweep nets and females were dissected to determine whether they had mated.
Next-generation larvae: Thirty small sample areas were assessed in each field for larvae and their feeding tents.
Crop damage: Damaged cranberries were counted at harvest.
What was the outcome?
The researchers found that the microencapsulated pheromone formulation successfully disrupted blackheaded fireworm reproduction.
Female fireworms collected from treated plots were significantly less likely to be mated. In fact, across the two study years, treated plots had 2.44 times more virgin females than control plots. The treatment did not change the overall sex ratio of captured insects, suggesting that the difference was related to mating rather than to a change in the number of females present.
Fewer mated females resulted in a reduction in the next generation of the pest. The researchers found 68% fewer occurrences of blackheaded fireworm larvae and their characteristic feeding tents in treated plots compared with control plots.
The treatment also reduced fruit damage. In the first year, treated plots had nearly 59% less crop damage than control plots. In the second year, damage was approximately 29.5% lower in treated plots, although this difference was not statistically significant. The variation between years highlights the need for additional field testing under different pest and environmental conditions.
Interestingly, the researchers did not observe the expected reduction in male captures in pheromone-baited monitoring traps. In fact, male captures were sometimes higher in treated plots later in the season. Male captures are an indirect measure of treatment efficacy: if sufficient pheromone is present in the environment, males should have difficulty locating the pheromone-baited traps. The unexpected results highlight how relying only on male trap counts, which is a widely used performance metric in mating disruption trials, could suggest that the treatment was not working, even though female mating, larval presence, and – in one year – crop damage were all significantly reduced.
Hover over the image to read the caption; click on the image to see full size.
What’s next?
The results suggest that sprayable microencapsulated pheromones have potential as a practical tool for managing blackheaded fireworm in organic cranberry production. The approach is particularly promising because it can be applied with standard spraying equipment and timed to match fireworm flight activity.
However, more research is needed to determine the field longevity and optimal number of applications of this sprayable formulation as well as how reliably the treatment reduces crop damage across different farms, pest pressures and growing conditions. Future studies could also investigate how best to integrate mating disruption with other pest management practices.
An important lesson from this research is that the success of mating disruption should not be judged by male trap captures alone. Measuring female mating, subsequent larval populations and crop damage provides a more complete picture of whether the technology is actually reducing the pest’s ability to reproduce and damage the crop.
This article is based on the following scientific journal article:
Pouët C, Labarre D, Cormier D, Lucas E. 2026. Mating disruption to control the blackheaded fireworm (Lepidoptera: Tortricidae) in organic cranberries using microencapsulated sprayable formulation. Journal of Economic Entomology. doi:10.1093/jee/toag213.
Stay tuned for more findings from Dr. Éric Lucas and Didier Labarre’s research team as they continue exploring integrated pest management strategies in cranberries – including herbivory induced plant volatiles and mechanical release of Trichogramma parasitic wasps!
Published August 31, 2026
Organic Science Cluster 4 is an industry-led research and development endeavour co-managed by the Organic Federation of Canada and the Organic Agriculture Centre of Canada at Dalhousie University and supported by the AgriScience Program under Agriculture and Agri-Food Canada’s Sustainable Canadian Agricultural Partnership together with over 80 funding partners.
