ALTHOUGH THEY are not harmful to humans, ACP can prove devastating for citrus trees -- such as oranges, lemons, grapefruits and Mandarins -- if they carry a fruit-destroying disease, called greening (HLB) disease that has no cure yet. While fruits from an HLB-infected tree is unmarketable due to its extremely sour taste and odd size, the disease has resulted in massive tree removal and significant financial losses across the US citrus industry.

"Our study shows that insecticide resistance in the pests may become an emerging problem for ACP control if effective resistance management is not practiced," said Dr Siddharth Tiwari,a postdoctoral research associate with University of Florida's Citrus Research and Education Center (CREC).

The new study, published in the journal Pest Management Science, was conducted to document resistance levels in Florida populations of ACP to commonly used insecticides.

Baseline susceptibility data for both adult and immature ACP were developed using a laboratory susceptible population as a comparison. Five field-collected populations of ACP were tested to estimate susceptibility levels in response to 12 insecticides.

The researchers found that certain populations of ACP have developed higher level of resistance to the insecticides, posing a great threat to the citrus industry that accounts forover USD 9 billion in Florida alone. Dr Tiwari along with his colleagues in the Department of

Entomology at CREC are working to manage psyllid, which will in turn reduce the disease spread. Their findings have called for the judicious use of insecticides to prevent the resistance from developing to high levels.

"These findings come at the right time when researchers and citrus growers are also working to fight this pest and HBL disease," said Tiwari said.