Cyromax and Larvafix: Pioneering Fly Management in Modern Poultry Operations

Introduction

The expansion of commercial poultry houses worldwide is driven by the increasing human population’s needs (Axtell 1999). In modern production systems, poultry are densely housed, leading to significant accumulations of waste such as manure, used litter, and deceased birds. These waste materials serve as ideal breeding grounds for fly larvae, leading to the proliferation of adult flies (Axtell 1986, 1999), particularly houseflies, which are the predominant species.

Flies play a crucial role in transmitting pathogens like viruses, fungi, and parasites across many regions worldwide (Banjo 2005). Adult flies can harbour over 100 pathogen species associated with more than 65 diseases affecting both humans and animals (Greenberg 1970-1973). The presence of high fly populations not only stresses animals and farm workers but also presents challenges to neighbouring properties and businesses.

Musca domestica, a common species in farm environments, poses significant sanitary concerns due to its high reproductive rate, feeding behaviour, and dispersal abilities. The abundance of organic waste in intensive animal production facilities creates favourable habitats for these insects to grow and thrive (Thomas 1993).

Life Cycle

The house fly undergoes complete metamorphosis, progressing through distinct stages of egg, larval (maggot), pupal, and adult. During winter, house flies can be found in the larval or pupal stage under manure piles or other protected locations. Optimal development occurs in warm summer conditions, allowing the house fly to complete its life cycle in as little as seven to ten days. However, under less favorable conditions, the life cycle may extend to two months. In temperate regions, 10 to 12 generations can occur annually, while subtropical and tropical regions may see over 20 generations. Female house flies are prolific egg layers, capable of depositing up to 500 eggs in batches of 75 to 150 eggs over a period of three to four days. (Krafsur 1989).

Fly Control

Effective fly control measures involve targeting both larvae and adult forms. While conventional biocides can suppress adult flies, this approach has a short-term effect. Larvicides and adulticides are more comprehensive solutions. Chemical treatment remains a critical component of fly control strategies on farms, but maintaining high hygiene levels is also essential for reducing fly populations.  In urban areas, fly control typically relies on trapping methods such as baited traps, sticky traps, and ultraviolet light traps, combined with the application of insecticides. However, there has been limited research on the use of repellents for fly control (Parashar 1993).

Larvicide

Insect Growth Regulators (IGRs) constitute a diverse group of insecticides that exert varying effects on insect-specific processes, disrupting their growth, development, and reproductive cycles. Primarily targeting immature stages, IGRs interfere with metamorphosis and reproduction, making them increasingly crucial in managing insect pests (Graf 1993; Retnakaran et al. 1985; Grenier and Grenier 1993). These regulators encompass different chemical categories such as juvenile hormones, chitin synthesis inhibitors, and triazine derivatives, each with distinct modes of action (Retnakaran et al. 1985).

On the other hand, commercially available insect repellents can be categorized into two main types: synthetic chemicals and plant-derived compounds sourced from essential oils. Many plant extracts have been identified for their repellent properties, marking them as effective alternatives in pest management (Coats 1994; Isman 2006).

Cyromazine (also known as CGA 72662 or N-cyclopropyl-1,3,5-triazine-2,4,6-triamine) is a novel class of Insect Growth Regulators (IGRs) derived from aziodotriazine herbicides, first discovered by Ciba-Geigy Ltd. in the mid-1970s. (Moreno-Mari et al. 1996; Graf 1993). Today, Cyromazine is used topically to manage housefly larvae in manure, as a feed-through agent in poultry marketed as Cyromax & Cyromax -DS by Stallen South Asia Pvt. Ltd.

Cyromazine is an insecticide used as an additive only in the feed for chicken layer hens and chicken breeder hens at <0.01 pound of cyromazine per ton of poultry feed. It is used for control of flies in manure of treated chickens. The maximum residue levels (MRLs) of cyromazine are not to exceed 5.0 ppm in poultry feed, and the feeding of cyromazine-treated feed must stop at least 72 h before slaughter (US. EPA 1999).

As an IGR, Cyromazine disrupts the molting process in insects. It is known for its stability against hydrolysis and photolysis, as reported by USEPA in 2006. When applied to chicken manure for housefly (Musca domestica L.) control, Cyromazine can remain active for 10 to 20 weeks, as demonstrated in studies by Mulla and Axelrod in 1983.

Researchers are exploring traditional remedies for innovative chemical compositions and new repellent properties. Various studies have highlighted the fly-repelling properties of plant oils such as clover, peppermint, geranium, neem, and turmeric (Sharma et al., 1993; Kant & Bhatt, 1994; Mafong & Kaplan, 1997; Isman, 2006; Krajick, 2006).

Vidaalprnaas (Nepeta cataria), an herbaceous native to Eurasia and North Africa, as well as prevalent in North America, has recently gained attention for its  larvicidal activity after topical spraying   application on  larval stages of flies showing  an effective killing of larval stage. There is also evidence supporting its spatial repellency (Peterson, 2001; Bernier et al., 2005; Trongtokit et al., 2005; Zhu et al., 2006). The larvicidal activity of Vidaalprnaas (N. cataria) is associated with the contents of 1,8-cineol, camphor, 4aa, 7a, 7ab-Nepetalactone, 4aa, 7b, 7aa-Nepetalactone, and thymol (Yang et al., 2020).

Mint oil, extracted through steam distillation from Mentha piperita leaves, has insecticidal properties against Musca domestica L . Some of the chemical components of these oils may interfere with the nervous systems in insects. M. piperita contains menthol, carvone and limonene, found in significant concentrations in peppermint oil, is known for its natural pesticide properties, effectively targeting larval of flies after spraying on manure (Robert 2001). M. piperita essential oil had the highest housefly larvicidal properties with a LC50 value of 104 ppm and exhibited 96.8% repellency and 98.1% oviposition deterrence at a 1% concentration (Morey and Khandagle, 2012). Kumar et al (2012a) found M. piperita oil achieved housefly larval LC50 of 0.54 ul/cm2 by contact and an LC50 of 48.4 ul/l by fumigation; it also caused 100% suppression on contact and with fumigation. The larvicidal activity of the mint family is associated with menthone and menthol, the major constituents present in these herbal plants (Kumar et al., 2011).

The insecticidal mode of action of herbal plant extracts like mint and catnip (vidaalprnaas) has only been hypothesised as active ingredients exerting their effects on insects through neurotoxic activities involving several pathways, notably γ -amino-butyric acid (GABA), octopamine synapses, and the inhibition of acetylcholinesterase (Corbett, 1974).

 Stallen South Asia Pv.t Ltd has introduced Larvafix, a larvicide containing Vidaalprnaas (Nepeta cataria) and Mint oil (Mentha piperita), as an effective solution for fly control in poultry farms.

Conclusion

In conclusion, Cyromazine ( Cyromax & Cyromax-DS ) has emerged as a valuable tool in the control of housefly larvae, offering stability and long-lasting effectiveness in poultry farms and other settings. Its ability to disrupt the molting process in insects makes it a key component in integrated pest management strategies. On the other hand, plant-derived compounds such as herbal oils, including mint oil and Vidaalprnaas(Larvafix)  showcase promising repellent properties against flies.