Mixing it Up! A Technician’s Guide to Cockroach Baits

Cockroaches are one of the most difficult urban pests to manage. This is due in large part to their resistance to many of the most commonly used insecticides, particularly residual pyrethroid sprays. Cockroach baiting remains one of the most effective management strategies and is strongly supported by scientific evidence. However, baits can fail due to either physiological (e.g., detoxification, insensitivity) or behavioral (e.g., aversion, reduced palatability) resistance. In addition to taking an integrated approach to cockroach management (e.g., using multiple management techniques), it is critical that baits are rotated regularly (bi-monthly, quarterly, etc.) to prevent bait failure and delay the onset of insecticide resistance. When rotating baits and other insecticides, it is important to not only switch products, but to ensure that the active ingredient you switch to has a different mode of action (MOA). Insecticidal products are divided into different classes based on the active ingredient’s MOA. Detailed information on insecticide classification can be found on the Insecticide Resistance Action Committee (IRAC) website (https://irac-online.org/modes-of-action/).

Cockroach Bait MOA Table >>>

The chart at right provides essential information on cockroach bait active ingredient classes which can be used to develop a bait rotation strategy. By properly rotating baits, the onset of resistance can be delayed and the life of all cockroach bait products can be extended.

Cockroach Baiting Tips

The following are tips for pest management technicians to help use cockroach baits in their accounts in the best way possible. Remember, like any type of pest control, the most effective treatments are those that take an integrated approach and are individually tailored for each account. Baits are a great tool for controlling cockroaches, but they should always be part of a larger integrated pest management plan.

Rotate baits regularly. It’s ultimately up to each company how frequently they choose to rotate baits (bi-monthly, quarterly, semi-annually, etc.). While it would be ideal to rotate baits with every visit, this often isn’t practical. The key is to avoid over-use of the same bait and to be on the lookout for bait failure. If you suspect a bait is failing, it is worth collecting some cockroaches and testing specific baits for efficacy (consumption and mortality).

Give them choices. Cockroach populations can have different preferences and possible resistance to baits, therefore it is never a bad idea to try more than one bait near an aggregation to see which they accept. This will help determine if a population will take your bait during the current service rather than waiting to find out during the next service.

Don’t be stingy with baits. Baits are attractive to cockroaches, but only over short distances and for a short time after application. To be effective, baits need to be dispersed throughout infested areas to ensure all cockroaches encounter them. It is also important to replenish baits as they are consumed, which often happens in heavily infested accounts.

Dabs, not lines. Gel baits should be applied following the label instructions. That said, the best practice is to apply small dabs of gel bait about the size of a pea throughout the infested area. Gel baits applied in lines/strings waste product, do not increase efficacy, and may be a label violation depending on the bait.

Quality over quantity. It is most important that you get the bait into the correct locations; a smaller portion of bait applied correctly is much better than a large amount of bait applied incorrectly. This requires a thorough inspection and knowing where cockroaches are located.

Consider bait stations for some accounts. Bait stations are often overlooked but can be a useful tool for certain accounts. While often less palatable than fresh gel baits, bait stations are formulated as a harder matrix which typically can withstand a wider range of temperatures and humidities, increasing efficacy in accounts with more extreme environmental conditions.

Recommend but don’t require sanitation. While sanitation can greatly improve bait efficacy, multiple studies have shown that when baits are properly applied and dispersed throughout the infested area, they can be effective even with poor sanitation. That said, clients should be informed of the value of sanitation and the risks involved with trying to control cockroaches in structures with poor sanitation (delayed control and reduced efficacy of treatments).

Move the fridge! Often, the refrigerator is left untouched. The fridge provides a source of warmth (compressor), water (drip pan), and food (food that falls behind it) for cockroaches and is often one of the most infested areas. Do not neglect to inspect and treat behind the fridge.

About the author: Zach DeVries is an assistant professor in the Department of Entomology at the University of Kentucky. His lab studies cockroaches, bed bugs and other pests in the urban environment.

CAUTION: This publication is not an endorsement of any product, only a list of the most common products available to pest control operators. Also, some pesticides or practices mentioned in this publication may not be legal in your area of the country. If in doubt, please consult your state regulatory agency. ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR THE PRODUCT YOU ARE USING AND ABIDE BY LOCAL, STATE, AND FEDERAL RULES AND REGULATIONS.

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