Vampires aren’t the only pests repelled by garlic

Fly control in cattle operations is always a hot topic as the weather warms up. Flies can cause significant losses in beef and dairy animals by reducing weight gain and milk production.

Pyrethroid insecticides are widely used to combat the problem. A pyrethroid is an organic compound similar to natural pyrethrins produced by flowers such as chrysanthemums. These insecticides are effective on flies and generally harmless to humans, but they are toxic to fish and desirable insects such as bees, dragonflies and mayflies.

These safety concerns and increasing resistance indicate the need for alternative control tactics. There are a variety of fly-control technologies on the market today, including botanical extracts and oils with bioactive compounds that can exert different modes of action.

One of the most promising is the Allium sativum species—also known as garlic. Garlic oil and extracts are identified by EPA as “minimum risk pesticide products” under the Federal Insecticide, Fungicide and Rodenticide Act, a designation given when the risk to the public and the environment is low enough to not require all the data and review necessary for registration.

Allicin is an active ingredient in garlic that has antibacterial, antifungal, antiviral and antiprotozoal activity. It also acts as a natural insect repellent. After consuming garlic, animals will secrete the allicin, which cannot be metabolized. The familiar, pungent garlic odor is emitted through the animals’ skin and breath and makes them less appealing to flies.

The head, neck, back line and tail head are where the greatest repellent effect is seen. The effect will be influenced by level of intake as well as weather and environmental conditions.

Anecdotal evidence from producers using garlic-enhanced salt or mineral seems to be positive. And while there is limited formal research on garlic, the few existing studies have consistently shown fewer flies when cattle were fed supplements containing garlic. Most reports indicate results in the 40% to 60% reduction.

Garlic has also shown some effect on repelling ticks. A 2017 article in the International Journal of Acarology (the study of mites and ticks), reported that a water-based solution with garlic concentration of 25% can be safely applied on animals to remove ticks and 10% to prevent ticks from attacking animals for a period up to a week.

While any reduction is good, keep in mind that the EPA says a compound needs to control more than 90% of targeted pests to be considered a conventional insecticide.

In response to requests for MFA minerals with garlic, we have added the ingredient to several versions of our popular MFA Ricochet FesQ Max mineral with Shield Technology. Some of these garlic products are floor-stocked at our feed mills while others require a minimum 2-ton order. Check with your local MFA manager or livestock representative for product availability.

Plant-derived bioactive compounds such as allicin typically exhibit short residual activity, which can be seen as an advantage or disadvantage, depending on who is buying the drinks. It’s important to remember that garlic only works as a repellent and does not kill insects. Producers wanting to reduce the impact that flies have on their cattle herds need to tackle the problem with a multi-faceted approach, both internally and externally.

Even when using products containing garlic, producers should also consider feeding an insect growth regulator in mineral to interrupt the flies’ life cycle and reduce future population numbers. External fly-control measures can include insecticide sprays, dusts, backrubbers or oilers. Using multiple modes of action helps prevent or delay development of resistance by pest populations.

Bottom line, bioactive botanical compounds such as the allicin in garlic are not a cure-all for controlling horn flies, stable flies or ticks, but they may offer environmentally friendly alternatives to synthetic pesticides and improve upon safety and resistance buildup. These advantages, and the variety of available compounds, are potentially valuable tools for an integrated pest management program. We’ll likely see more development and research in this area.