Insects in grain Image Credit: Gulf News Archives

Dubai: Stored product insects (SPIs) are the world’s most expensive pests and can prove to be a huge challenge if timely action is not taken to wipe them out, according to a pest control expert.

SPIs, which cover a range of insects like beetles, moths, weevils and mites, can be found in stored food products like cereal, grains, nuts, cheese, flour, rice, oats, dried fruits and seeds which are kept in kitchens, larders and store rooms.

Dinesh Ramachandran, technical manager at Rentokil National Pest Control, which takes up pest control across thousands of homes in the UAE, said an SPI infestation manifests itself in many ways.

When one sees small beetles crawling on kitchen counters, tiny caterpillar-like insects moving on the walls or ceiling or moths flying about in the area, it means the SPI infestation is widespread.

But more often than not, signs of the infestation are evident from larvae or webbing found in and around food storage containers, packets or bags, in cracks and crevices around shelves and windows and as holes in paper packages.

“Nearly all damages by SPIs are caused by the larvae,” said Ramachandran.

While the SPIs eat the food they are found in, their breeding and waste also contaminate the products, making them unfit for human consumption. The products have to be destroyed immediately.

Prevention

Ramachandran said, “Good hygiene, stock rotation and correct storage practices are the best way to prevent and control SPI infestations. Large-scale infestation, of course, can be controlled by fumigation. Residual/labelled insecticides are applied to cracks, crevices and shelves in storage areas after removal of products. Insect growth regulators and pheromone traps are also used.”

He said, “To prevent re-infestation, all grain products should be stored in containers with tight fitting lids or put away in the freezer. Old grains must be cleared and storage area dusted in order to keep away unwanted pests.”

Last week, Rentokil Initial’s group category director Mark Reader, who addressed a Dubai conference on the challenges facing food safety worldwide, said flying and crawling insects make up 74 per cent of pest infestations in the global food processing chain. He said 60 per cent of respondents in a survey reported annual revenue losses of between one to nine per cent as a result of SPI infestation.

Signs of infestation:

  • Exit holes in grains
  • Damp and mould in food products
  • Insect tracks in flour, rice, oats and cereals
  • Webbing
  • Waste material in food items