Thousands of hectares of rice in several districts of Prey Veng province are facing damage as rice whiteflies (Aleurocybotus indicus) continue to devour crops following a recent outbreak.

According to Nhor Khuy, a commune agricultural officer based in the province’s Preah Sdach district, the destruction has been ongoing for approximately two weeks, but initially, farmers did not pay much attention until the infestation worsened this week.

"There has been no decline in [rice whitefly] numbers so far because these pests are difficult to eradicate. In one commune, they are infesting between 500 to 600 hectares. In total, about 6,000 hectares in the district are affected,” Khuy said.

He estimated that 50 per cent of the infested rice crops could be damaged.

Khuy explained that the whiteflies suck nutrients from the plants, causing deficiencies and impeding photosynthesis.

He said the affected rice turns reddish, becomes stunted and begins to wilt. If the rice is heading (flowering), the pests prevent the grains from emerging or cause them to stunt.

Khuy mentioned the primary method of control is currently pesticide spraying, but it is less effective on mature rice because the chemicals do not reach the flies effectively.

He said farmers are advised to use a mixture of two to three different pesticides and to cooperate with neighbouring fields to spray simultaneously for higher effectiveness.

"Spraying can reduce their numbers, but it cannot eliminate them entirely. [It] kills about 20 to 30 per cent of them. Farmers need to spray multiple times, every four to five days, to keep the infestation under control until the rice grains emerge," he advised.

Khuy stressed that farmers need to apply supplementary fertilisers to strengthen the rice, which incurs additional costs, but may recover some yield. Without any pesticide application, the entire crop could be lost, he noted.

"It is a concern because the scale of destruction is significant, and we do not yet have a way to completely eradicate them. We can only control them. Farmers are encountering this issue for the first time this year. If they had experienced whiteflies before, they might have been able to manage, but this is new for them," he added.  

Khuy said the outbreak initially occurred in neighbouring Vietnam and later spread to Cambodia, particularly in provinces along the shared border, noting several other districts in the province are also experiencing infestations.

Ouk Samnang, director of the provincial Department of Agriculture, Forestry and Fisheries, could not be reached for comment.

Experts from the agriculture ministry are visiting the province to help with the situation.

A team led by Kong Kea, director of the rice department at the agriculture ministry’s general agriculture department, visited the district on July 1.

"Field inspections have shown that the damage is severe and spreading to other communes,” stated a social media post from the ministry.

During a meeting with farmers in Lvea commune, Kea spoke about the history of the infestation, conditions for whitefly outbreaks and the damage caused.

He recommended various control and eradication methods, including the effective and safe use of agricultural chemicals and advised farmers to spray in the morning and evening.

According to the ministry, Kea also instructed the provincial agriculture department, especially commune agricultural officers and local authorities, to assess the impact of the infestation and report to the ministry’s general agriculture department for timely intervention. The team will continue to stay in Prey Veng to participate in assessments and interventions, as per the ministry.