[Annual Cockroach Issue] German Cockroach Management: It’s No Picnic

When it comes to German cockroaches in public housing, managing heavy infestations to get them under control is no picnic. Housing authority contracts tend to go to the lowest bid, selling pest management services short and putting technicians in a precarious situation. They simply don’t have the time to do the job right.

“Contracts are being undersold in public housing and that’s why we are having these massive infestations,” says Dr. Dini Miller, professor of urban entomology at Virginia Tech, Blacksburg, Va. In addition, the “multiple small bait placements” theory does not work in this environment, according to Miller.

“We were taught to put out gel bait that is the size of a quarter of a dime, and put out hundreds of these placements. Can you imagine how much time it takes to do that?” Miller asks. “With heavy infestations we need to talk about many large bait placements. Lack of bait volume is the number one reason why we have these spectacular infestations.”

Adding fuel to the fire, many public housing facilities have been treated with countless products over the past 60 years and much of that residue remains, posing bait contamination concerns. Another challenge includes massive amounts of clutter.

Miller and her crew of students set out to find different techniques to manage application speed and bait distribution out in the field to deal with these severe infestations. Her research is typically funded in part by manufacturers to test their products or those in development. According to Miller, it’s a win-win for both parties.

“Universities don’t have tons of money and they don’t support our labs, so much of urban entomology is funded through sponsored research that we do for manufacturers,” Miller says. “The advantage for me is that I get a first-hand look at the products, seeing how they work and how they perform in the lab and field.”
 

The Quest for Clarity.

The Richmond Redevelopment & Public Housing Authority (RRHA), established in 1940, today houses approximately 10,000 people in 4,000 units. Statistics show the average resident income is about $11,000 per year and the development has an average occupancy rate of 9.4 years, despite the housing authority view that occupants turn over every two years. Turnover every two years would mean the units would be repainted, and it was obvious to Miller that much of the residue had been there for a long time.

Wanting to find apartment complexes that were very infested, Miller and her team hit the jackpot with the RRHA.

“We found the largest, most spectacular infestations I have seen in my career. There are sanitation problems, water issues, clutter and the cockroaches have a lot of access to food. The cockroach populations were flourishing and the infestations have been there for a long time,” says Miller. “We found cockroaches everywhere — in the storage units, living in a deck of cards, on walls, in the sink in the cooking oil.”

Currently, one facility at this location is under contract for five years, with Richmond paying $2,478 for quarterly treatments. They are treating 458 units working eight hours a day per week.

“If the math is correct, that means $6 a door, but the RRHA doesn’t figure it out that way, they chose the low bid,” Miller says. “I met the owner of this company and found out they are using only one technician. That means this technician is checking 92 units per day, 12 units every hour and spending 5 minutes per unit — including walking in between units, opening doors, taking breaks, etc. Under this scenario the technician doesn’t have enough time to control the infestation. He can put bait out, step on a few but that’s about all. The technician does not have enough time to put out enough bait at $6 per door.”
 

Pre-trapping/Spot Selection.

In April 2010, Miller and team placed three sticky traps in each unit for 24 hours: above the sink, below the sink and behind the toilet. They returned the next day to pick up the traps and count the cockroaches. She used large, low-laying traps so she could see the differences between units. Students collected the traps to determine baseline infestations, counted 8,186 cockroaches in 83 units and selected 40 of those units for testing. For statistical replication each formulation was to be used in two different buildings and no building would have more than one bait. The team planned to put bait out and monitor at days 3, 7, 14, 30, 60 and 90.

Soon after, Miller learned the manufacturer would not be able to supply the experimental bait until July. Since the contract pest management company was to conduct a quarterly treatment in June, Miller was concerned that treatment would ruin the testing and felt it was best to look for another site.

Luckily, from a research perspective, the Petersburg Redevelopment & Public Housing Authority was experiencing the same, if not more intense, infestations. These units posed a new challenge due to shower stalls that had been remodeled with vinyl covering, which was a major source of infestation.

“Pre-trapping at the Petersburg location was truly my career high. We trapped an average of 463 cockroaches per unit over a 24-hour period. Granted it was in August when there’s a population increase when they will double and triple their population size,” Miller says.

Shortly after the bait was available, Miller learned that the RRHA was still experiencing heavy infestations and wanted her team to come back and continue where they left off.

“So we go back to pre-trap the same units in Richmond and our original trap counts have doubled, with an average of 464 cockroaches per unit in 24 hours. We pre-trapped in April and then they had their quarterly service in June; what did they get for their $2,478? They doubled their number of cockroaches,” Miller says. “If these were stocks, everybody would be thrilled.”

Miller determined the cockroach population warranted 30-40 grams of bait in each apartment to gain control. On Day 1, all units received 30 grams of bait. Additional bait was applied on Day 14, depending on the infestation level (see Table 1, on the right).

“If you are looking at a situation where we were able to catch 464 in 24 hours, you better put out a significant amount of bait, not just 3 grams,” Miller says. “But here is the issue — putting out these small bait placements was taking a ton of time.”

So, they hatched a plan. High-tech stuff. They put a gram or so of bait on several small squares of wax paper, wrapped them up like a “bait burrito” or “cockroach cannoli” to protect the bait from contamination and then took handfuls of them to place wherever they saw cockroach activity. They also cut up straws and placed bait inside. They were able to tape these horizontally above kitchen windows, to sink cabinets and under microwaves.

“This worked much, much faster. It won’t necessarily be a good idea for small infestations because you’d waste bait, but for these massive infestations, you have got to get a lot of bait out,” Miller says. “Despite all of the competing food sources, when we put the bait out, the cockroaches went running to it. And there were enough cockroaches crawling around that I promise you in 24 hours we had no bait left.”

With the contract pest management company only servicing this location quarterly, they would never get control, according to Miller. The company had been using one of the same bait formulations, and when residents saw that Miller and her team was using it, they doubted its effectiveness.

“They were telling us it didn’t work. I said give me three days. The difference is quantity,” Miller says. “I had so many people come up to me saying they couldn’t believe how many dead cockroaches they had to sweep up. They were impressed, and after three days, everybody loved us.”
 

Revealing Results.

In Richmond, by Day 60 using all of the bait formulations, they had a 90 percent decrease in population; Petersburg saw a 70 to 90 percent decrease. Trapping also had an impact on population levels. In Richmond, trapping alone removed more than 47,000 cockroaches from April through July. In Petersburg, trapping removed nearly 46,000 in 30 days, due to the summer increase in population.

Even in the controls there was a decrease as the sticky traps were taking out enough cockroaches to have an impact.

“All the baits worked very well. Using heavy bait volume worked very well, and this was during summer. If we had been able to treat in January when populations are at their lowest, we would not have seen this huge summer increase,” Miller says.

Miller says that previous failures to reduce the population were not due to bait failure, but due to lack of bait volume, and the bait burritos and cockroach cannolis were key to getting bait distributed in a timely fashion. To get the reductions Miller and her team required an average application of 50 grams per unit over the course of two applications. The average application rate was 10 minutes to apply 20 grams in a unit. The pest management company cost per unit to get heavy infestations under control would average $15-18 per unit. Finally, a January start would reduce overall costs.

“What I am talking to public housing about now is rewriting their contracts. They need to start treatment using monitoring to identify the top 25 worst units for first three months, and treat only those units. That would give the company and the technician time to blast those top units out and the next quarter, they could work on next 25 units, and so on,” says Miller. “I think that’s the only way you’re going to get the cockroaches out of these particular housing authorities.”

The author is PCT contributing writer and can be contacted at cbrazell@giemedia.com.