Which of the following is a sign of a cockroach infestation?

• A. Strong citrus odor
• B. Sticky residue on work surfaces
• C. White powder near corners
• D. Strong oily smells

Answer: (D)

A strong oily odor is a classic sign of cockroach activity. Cockroaches release pheromones and bodily secretions that, when their numbers are high, produce a distinct oily, musty smell—often noticeable in areas like behind appliances, under sinks, or in dark corners of a kitchen. This odor tends to become stronger as the infestation grows, making it a key indicator to investigate further.

Other options don’t fit as reliably. A citrus odor usually comes from cleaners or fragrances, not roaches. Sticky residues on surfaces are more likely to be grease, food, or general grime rather than a sign of cockroaches. White powder near corners is commonly boric acid or another pesticide used for treatment, not an inherent sign that an infestation is present. If you detect a strong oily smell, inspect for roach signs like droppings, shed skins, and egg cases, and involve licensed pest control to address the problem.