Why do cockroaches keep coming back after I spray?
Because sprays only hit the adults out in the open. The nymphs stay in the wall voids and behind appliances, and the egg cases aren't affected, so the population rebuilds in weeks.
German Cockroach (Blattella germanica)
Reviewed by William "Willy" Vizcarrondo, NYS Certified Pesticide Applicator (C1825832). Updated September 23, 2026.
Quick facts
The German cockroach is the small, fast, light-brown roach that infests kitchens and bathrooms in Long Island apartments, multifamily homes, and restaurants. It lives only indoors with people, breeds faster than any other roach, and is the reason "we sprayed and they came back" is the most common cockroach story we hear.
| Size | 1/2 to 5/8 inch, adults with wings but they rarely fly |
|---|---|
| Color | Light brown with two dark stripes behind the head |
| Look-alikes | American cockroach (much larger, reddish, comes up from sewers and basements), Oriental cockroach (dark, glossy, damp basements) |
| Where you'll find it | Kitchens and bathrooms: behind the fridge and stove, under the sink, inside cabinets, in wall voids near warmth and water |
| Active on Long Island | Year round indoors |
| Danger level | Asthma and allergy trigger, food contamination |
Long Island season
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
German cockroaches live entirely indoors, so there is no off-season; they're worst wherever a kitchen is warm and damp.
How to identify it
Half an inch to five eighths of an inch long, light brown, with two dark parallel stripes running from the head down the back. Nymphs are smaller, darker, and wingless.
If the roach is big, reddish-brown, and over an inch long, it's an American cockroach coming up from a drain or a basement, which is a different problem with a different fix.
Signs you have them
- Live roaches in the kitchen at night, especially when a light goes on
- Small dark droppings like pepper or coffee grounds in cabinet corners and drawer tracks
- Brown egg cases about 1/4 inch long behind appliances
- A musty, oily smell in heavy infestations
- Roaches seen in daytime, which means the hiding spots are full
Why it matters
German cockroaches produce at least a dozen distinct allergens that are potent asthma triggers, and they contaminate food and surfaces as they feed (UF/IFAS). A female carries an egg case of 30 to 40 eggs, produces about one a month, and a population can turn over 3 to 6 generations a year. One pregnant female in a kitchen is enough to start an infestation.
Can I handle it myself?
A light problem in a single-family house, sometimes, with gel bait and serious cleaning. Foggers and baseboard sprays don't work on German roaches: the youngest nymphs never leave the wall voids to get sprayed, and the population rebuilds from them.
Gel baits work because roaches eat each other's droppings and dead, so the bait spreads through the colony (UF/IFAS). In an apartment or multifamily building, one unit usually can't be cleared alone, because roaches move between units through shared plumbing walls.
How Bobby Bugs treats it
Inspection to find every harborage, gel bait and insect growth regulator placed where the roaches actually live, crack-and-crevice treatment, and a follow-up. Cockroach treatment carries a 60-day written guarantee.
Related answers
Frequently asked questions
Can German cockroaches come in from outside?
No. They live only indoors with people and spread in boxes, bags, used appliances, and through shared walls in multifamily buildings.
Do I need to leave the house for a roach treatment?
Usually not. Gel baits and crack-and-crevice work don't require you to leave. We'll tell you before the appointment if anything is different for your job.
Are German cockroaches dangerous?
They're one of the strongest indoor asthma and allergy triggers there is, and they contaminate food. Cleaning with soapy water and a rinse removes the allergens; dry wiping just spreads them.
Sources
Think you have German cockroaches? Call (516) 509-6001 for a free written quote.