ROB RIESENMAN shows Guyanese cockroaches in various stages of development. Democrat photo by Shelly Thorene

ROB RIESENMAN shows Guyanese cockroaches in various stages of development. Democrat photo by Shelly Thorene


Unique biz: Call them Dubis, not roaches

By From page A1 | December 12, 2012

If you want a unique gift for someone on your list — a really, really unique gift — then Rob Riesenman of Dubi Deli might have just the thing. For reptile owners, Riesenman can offer some of the best live reptile food around, great fishing bait or, for gardeners, a couple of bags of cockroach frass could be the ticket for a thick, healthy lawn.

Riesenman, a hardware designer at Intel, breeds Blaptica dubia (Guyana spotted roaches) as reptile feeders in a warehouse in Shingle Springs. “Anything that will eat a cricket, will eat a cockroach,” said Riesenman, “and the roaches have 36 percent more protein, so they are a superior feeder.”

He began raising the dubi, a name he invented because people have negative associations with the word “cockroach,” after he found they were good feeders for his bearded dragon lizards. “But they were expensive, so I started raising my own.”

Friends who raised bearded dragons or other reptiles asked if they could have some of his dubi. “Then a friend called me and said since he’d been feeding dubi to his dragons, their egg production was up, they bulked up better and the females breeders recovered quicker,” said Riesenman.

With the rapid growth of the reptile industry and the shorter supply of feeders, it seemed like a good business to start.

“The problem was how to grow them in the high volumes that some breeders need to purchase, how to keep them contained and at the right temperature. It took about four years to figure all that out and build my colony,” said Riesenman. “Now I’m probably the only one in the world with this size inventory.”

Dubi are slow growing, taking three-six months to mature  and have a long life-span. These are advantages if they are bought in bulk as feeders, since they will stay the size needed for weeks.

“Crickets grow so quickly that many are too big to feed to the animal they are purchased for, if they are bought in bulk and buying in bulk saves money,” said Riesenman.”

They are poor climbers who can’t climb glass or plastic, so if someone leaves the lid off the terrarium, there are no worries about escapees. They can’t jump either. Adult males are the only ones that have wings and Riesenman said they fly sluggishly, like turkeys, and are easy to catch. Dubi are non-infesting roaches, which means that if one does escape it won’t take over your home.

“Less than 1 percent of roach species are infestation pests,” said Reisenman. “That seems to concern people the most.”

The dubi live in large plastic bins in a warm warehouse room.They eat roach chow, vegetables and fruits — just about any vegetarian fare except potatoes. Females have about 30 babies each month.

The bins are cleaned weekly. Roaches are placed into long wooden bins with screens at the bottom to sift out the waste. They are sorted according to size, from 1/4 inch nymphs to 1 3/4 inch males, and placed in containers with egg crates, food and water crystals before being shipped to reptile owners all over the United States. Riesenman has created his own prototype equipment and system to raise, ship and sort his little friends.

With a warehouse of millions of dubis in dozens of bins and screening bins and 4 or 5 tons of poop bagged up or waiting to be bagged up, you’d expect a horrific smell. There is an odor, reminiscent of a burn barrel, but it’s not strong. With a couple of dozen dubi in a bin, you probably wouldn’t notice it at all.

“They are friendly too,” said Riesenman. They are non-aggressive, unlike crickets. “If your animal doesn’t eat all the crickets  you put in the cage, the crickets will pick at the animal. But the dubi don’t  harm other animals. They don’t even harm each other.”

The business was going great guns, but there were bags and bags of dubi poop, also known as frass.

“When I first started raising dubi, I just threw it in the back yard of my house, ” said Riesenman, who lives in El Dorado Hills. “Then I noticed that the foliage was burned and the knee-high plants that were at the bottom of the slope where water had carried the frass were huge — over the top of my head.”

Curious about whether cockroach frass was a good fertilizer, he had it analyzed and asked a few friends to try it in their gardens.The analysis found dubi poop to be high in nitrogen and having potassium and phosphorus. Friends reported positive results on their gardens, particularly grass. Riesenman began thinking about a byproduct business. When he discovered that the dry, crumbled parts from dead roaches were another good source of nitrogen, it was even better.

Dubi frass is light and dry, almost like sand. It has little odor, unlike chicken manure.

“The frass is a fast release fertilizer  and the dead bugs are a good slow release fertilizer,” said Riesenman. He isn’t geared to bag it and sell it yet, but often friends and friends of friends will ask for it.

“I would sell it for probably a dollar a pound — 50 cents a pound for big purchases,” said Riesenman. “I’m going to take it to the UC Davis extension and see if they want to try it on different types of plants and I want to see if nurseries around here are interested in it.”

He’s planning to expand the feeder business and also to start making compost teas. Now that there’s a use for the frass, the business is almost completely green. And it’s quiet because the dubi don’t make noise.

If you want to give someone a bag of dubi frass for Christmas, you can call Rob Riesenman at 916-538-DUBI(3824). For reptile feeders check the Website at

Contact Wendy Schultz at 530 344-5069 or [email protected] Follow @wschultzMtDemo on Twitter.

Wendy Schultz

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