SA facing plague of cockroaches, says pesticides group

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South Africa is in the grips of a “near-pandemic outbreak” of cockroaches that is seeing the world’s most hated household pests scuttling about in their numbers in homes and businesses throughout the country, according to CropLife South Africa.

The very wet and humid summer unleashed a large-scale infestation of German cockroaches in all communities in South Africa, writes Elriza Theron, marketing and communications manager for the pesticides lobby group, in a recent article.

“Cockroaches are usually ubiquitous but calls to the CropLife SA emergency line point to a massive surge in German cockroaches all over the country. It is not only climate that spurs on their numbers but also unhygienic conditions that prevail in South Africa.”

While the prolific critters are primarily active at night, the outbreak is of such magnitude that the insects are running around during the day in many homes, she said. 

“Homeowners, the fast-food sector, retail sector and hospitality industry should act quick to stop the tide of cockroaches in South Africa.” 

Mike Picker, an emeritus professor in the department of biological sciences at the University of Cape Town, said Theron’s article indicates an outbreak mainly in the summer-rainfall parts of South Africa, where there were unusually hot and humid conditions this summer. 

“I do not have any other information confirming an outbreak there, but since these environmental conditions speed up the life cycle of many insects, it’s quite possible that this was the case,” he said.

The German cockroach originates from tropical parts of Asia. 

“The reported population increase would need to have started in December 2022. The life cycle of this heat-adapted species is fastest under warm and humid conditions.”

Picker said he had not personally seen any dramatic increase in the German cockroach in the Western Cape, which did not have an unusually hot or humid summer. 

“However, the larger American cockroach does appear to be more common now in domestic situations in Cape Town than previously. Pest control companies have confirmed a greater number of callouts related to cockroach infestations in Cape Town this year.” 

It, too, originates from tropical regions — caves in West Africa — and its increased abundance in Cape Town “may reflect milder climatic conditions as the climate in the Western Cape appears to have changed in the past decade”, he said. 

“Although this species typically thrives in artificially-heated areas in homes (often aggregating behind stoves and fridges), the highest numbers occur in sewerage pipes. The cockroaches venture from the pipes at night, often emerging from drains and entering households.” 

Pouring a strong bleach solution or a small amount of granular swimming pool HTH into the drains will eliminate the cockroaches, Picker advised.

However, Noel Coston, of Effective Solutions Pest Control, said the cockroach situation is “quite normal” in Gauteng. “I’ve done a number of treatments recently but nothing major that I think one should be concerned about … 

“We’ve been doing this for 29 years and we sometimes get called out to people’s homes or offices and they say, ‘Oh, we’ve got a major infestation of cockroaches,’ and you get there, and you do a thorough spray, and you see five cockroaches and they it’s a major infestation because … one is one too many. It’s a very subjective situation.”

He is more concerned about the proliferation of rodents in Gauteng. “There’s a major rodent problem because of the inordinate amount of litter lying around and drains being blocked with litter. Rodents are having a feast. 

“We’re seeing an increase in calls for rodents. Normally rodents are more active in winter, but for the past six, eight, 10 years or so, we’ve had rodent calls throughout the year because of the inordinate amount of litter on the roads and in the drains.”

Unfortunately, Theron said, the surge in cockroach numbers had triggered a large-scale  unlawful use of pesticides that are not registered for indoor use, with possible disastrous effects. 

“CropLife South Africa warns all citizens to abide by the statutes of the country and only use registered pesticides strictly according to their label instructions to avoid health impacts on themselves, their families or their clients. 

“Do not buy unlabelled pesticides in small containers from social media advertisers or street vendors as those products are likely to pose a severe hazard and risk to people when applied indoors … The cockroach outbreak does not warrant unlawful activities that pose a grave risk to people’s health.”

Controlling cockroaches in the home, Theron said, starts with cleaning up refuse and leftover foodstuffs. 

“A dirty kitchen that is littered with leftover food and freely available pet food needs serious intervention to deny these unsavoury critters from invading a home and setting up a colony.” 

Rubbish must be secured in bags, plastic bins or drums which can’t be accessed by insects. Floor surfaces, as well as potential breeding spots and hideouts in kitchens, pantries and bathrooms must be thoroughly washed and disinfected with a diluted solution of domestic bleach.

Places that attract and harbour cockroaches include electrical appliances, such as fridges and washing machines; cupboards under kitchen and bathroom basins; drainpipe cavities in walls; food cupboards; outdoor drains and dark, enclosed areas, such as garages.

“Cockroaches enjoy the heat and humidity underneath electrical appliances and basins, and that is where they often set up breeding colonies.”